[FFmpeg-devel,v7,1/2] libavformat/dvdvideo: add DVD-Video demuxer powered by libdvdnav and libdvdread

Sorry for the quick follow-up to v6, I wanted to get this update out now hopefully
before v6 is actually reviewed. v7 fixes a few documentation typos, options descriptions,
and log messages: nothing major. I also flattened this out to be a 2-patch set
with subtitle palette support.

This is the result of >1yr of research and I am now very satisfied with it's result.
I will not make any more changes at this point unless it is outcome from a review.
If the community decides to merge it, I am happy to continue to improve it with support for
seeking, probing, and tests.

Thank you so much,


Signed-off-by: Marth64 <marth64@proxyid.net>
---
 Changelog                 |    2 +
 configure                 |    8 +
 doc/demuxers.texi         |  129 ++++
 libavformat/Makefile      |    1 +
 libavformat/allformats.c  |    1 +
 libavformat/dvdvideodec.c | 1410 +++++++++++++++++++++++++++++++++++++
 6 files changed, 1551 insertions(+)
 create mode 100644 libavformat/dvdvideodec.c

On date Sunday 2024-02-04 23:48:25 -0600, Marth64 wrote:
> Sorry for the quick follow-up to v6, I wanted to get this update out now hopefully
> before v6 is actually reviewed. v7 fixes a few documentation typos, options descriptions,
> and log messages: nothing major. I also flattened this out to be a 2-patch set
> with subtitle palette support.
> 
> This is the result of >1yr of research and I am now very satisfied with it's result.
> I will not make any more changes at this point unless it is outcome from a review.
> If the community decides to merge it, I am happy to continue to improve it with support for
> seeking, probing, and tests.
> 
> Thank you so much,
> 
> 
> Signed-off-by: Marth64 <marth64@proxyid.net>
> ---
>  Changelog                 |    2 +
>  configure                 |    8 +
>  doc/demuxers.texi         |  129 ++++
>  libavformat/Makefile      |    1 +
>  libavformat/allformats.c  |    1 +
>  libavformat/dvdvideodec.c | 1410 +++++++++++++++++++++++++++++++++++++
>  6 files changed, 1551 insertions(+)
>  create mode 100644 libavformat/dvdvideodec.c
> 
> diff --git a/Changelog b/Changelog
> index c5fb21d198..88653bc6d3 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -24,6 +24,8 @@ version <next>:
>  - ffmpeg CLI options may now be used as -/opt <path>, which is equivalent
>    to -opt <contents of file <path>>
>  - showinfo bitstream filter
> +- DVD-Video demuxer, powered by libdvdnav and libdvdread
> +
>  
>  version 6.1:
>  - libaribcaption decoder
> diff --git a/configure b/configure
> index 68f675a4bc..70c33ec96d 100755
> --- a/configure
> +++ b/configure
> @@ -227,6 +227,8 @@ External library support:
>    --enable-libdavs2        enable AVS2 decoding via libdavs2 [no]
>    --enable-libdc1394       enable IIDC-1394 grabbing using libdc1394
>                             and libraw1394 [no]
> +  --enable-libdvdnav       enable libdvdnav, needed for DVD demuxing [no]
> +  --enable-libdvdread      enable libdvdread, needed for DVD demuxing [no]
>    --enable-libfdk-aac      enable AAC de/encoding via libfdk-aac [no]
>    --enable-libflite        enable flite (voice synthesis) support via libflite [no]
>    --enable-libfontconfig   enable libfontconfig, useful for drawtext filter [no]
> @@ -1806,6 +1808,8 @@ EXTERNAL_LIBRARY_GPL_LIST="
>      frei0r
>      libcdio
>      libdavs2
> +    libdvdnav
> +    libdvdread
>      librubberband
>      libvidstab
>      libx264
> @@ -3520,6 +3524,8 @@ dts_demuxer_select="dca_parser"
>  dtshd_demuxer_select="dca_parser"
>  dv_demuxer_select="dvprofile"
>  dv_muxer_select="dvprofile"
> +dvdvideo_demuxer_select="mpegps_demuxer"
> +dvdvideo_demuxer_deps="libdvdnav libdvdread"
>  dxa_demuxer_select="riffdec"
>  eac3_demuxer_select="ac3_parser"
>  evc_demuxer_select="evc_frame_merge_bsf evc_parser"
> @@ -6761,6 +6767,8 @@ enabled libdav1d          && require_pkg_config libdav1d "dav1d >= 0.5.0" "dav1d
>  enabled libdavs2          && require_pkg_config libdavs2 "davs2 >= 1.6.0" davs2.h davs2_decoder_open
>  enabled libdc1394         && require_pkg_config libdc1394 libdc1394-2 dc1394/dc1394.h dc1394_new
>  enabled libdrm            && check_pkg_config libdrm libdrm xf86drm.h drmGetVersion
> +enabled libdvdnav         && require_pkg_config libdvdnav "dvdnav >= 6.1.1" dvdnav/dvdnav.h dvdnav_open2
> +enabled libdvdread        && require_pkg_config libdvdread "dvdread >= 6.1.2" dvdread/dvd_reader.h DVDOpen2 -ldvdread
>  enabled libfdk_aac        && { check_pkg_config libfdk_aac fdk-aac "fdk-aac/aacenc_lib.h" aacEncOpen ||
>                                 { require libfdk_aac fdk-aac/aacenc_lib.h aacEncOpen -lfdk-aac &&
>                                   warn "using libfdk without pkg-config"; } }
> diff --git a/doc/demuxers.texi b/doc/demuxers.texi
> index e4c5b560a6..ad0906f6ec 100644
> --- a/doc/demuxers.texi
> +++ b/doc/demuxers.texi
> @@ -285,6 +285,135 @@ This demuxer accepts the following option:
>  
>  @end table
>  
> +@section dvdvideo
> +
> +DVD-Video demuxer, powered by libdvdnav and libdvdread.
> +
> +Can directly ingest DVD titles, specifically sequential PGCs,
> +into a conversion pipeline. Menus and seeking are not supported at this time.
> +
> +Block devices (DVD drives), ISO files, and directory structures are accepted.
> +Activate with @code{-f dvdvideo} in front of one of these inputs.
> +
> +Underlying playback is fully handled by libdvdnav, and structure parsing by libdvdread.

> +ffmpeg must be built with GPL library support available as well as the switches
> +@code{--enable-libdvdnav} and @code{--enable-libdvdread}.

FFmpeg must be built with GPL library support available as well as the
configure switches @code{--enable-libdvdnav} and @code{--enable-libdvdread}.

> +
> +You will need to provide either the desired "title number" or exact PGC/PG coordinates.

> +Many open-source DVD players and tools can aid in providing this information.

unrelated, but it might be useful to have a -list-titles option to
show this information

> +If not specified, the demuxer will default to title 1 which works for many discs.
> +However, due to the flexibility of DVD-Video, it is recommended to check manually.
> +There are many discs that are authored strangely or with invalid headers.
> +
> +If the input is a real DVD drive, please note that there are some drives which may
> +silently fail on reading bad sectors from the disc, returning random bits instead
> +which is effectively corrupt data. This is especially prominent on aging or rotting discs.
> +A second pass and integrity checks would be needed to detect the corruption.

> +This is not an ffmpeg issue.

nit: FFmpeg (ffmpeg is usually a reference to the CLI command, while
FFmpeg refers to the projects and set of all libraries/tools)

> +
> +@subsection Background
> +
> +DVD-Video is not a directly accessible, linear container format in the
> +traditional sense. Instead, it allows for complex and programmatic playback of
> +carefully muxed MPEG-PS streams that are stored in headerless VOB files.
> +To the end-user, these streams are known simply as "titles", but the actual
> +logical playback sequence is defined by one or more "PGCs", or Program Group Chains,
> +within the title. The PGC is in turn comprised of multiple "PGs", or Programs",
> +which are the actual video segments which, for a typical movie, are sequentially
> +ordered. The PGC structure, along with stream layout and metadata, are stored in
> +IFO files that need to be parsed. PGCs can be thought of as playlists in easier terms.
> +
> +An actual DVD player relies on user GUI interaction via menus and an internal VM
> +to drive the direction of demuxing. Generally, the user would either navigate (via menus)
> +or automatically be redirected to the PGC of their choice. During this process and
> +the subsequent playback, the DVD player's internal VM also maintains a state and
> +executes instructions that can create jumps to different sectors during playback.
> +This is why libdvdnav is involved, as a linear read of the MPEG-PS blobs on the
> +disc (VOBs) is not enough to produce the right sequence in many cases.
> +
> +There are many other DVD structures (a long subject) that will not be discussed here.
> +NAV packets, in particular, are handled by this demuxer to build accurate timing
> +but not emitted as a stream. For a good high-level understanding, refer to:
> +@url{https://code.videolan.org/videolan/libdvdnav/-/blob/master/doc/dvd_structures}
> +
> +@subsection Options
> +
> +This demuxer accepts the following options:
> +
> +@table @option
> +
> +@item title

here and below: you might use @var{TYPE} to denote the argument/type of the
option

> +The title number to play. Must be set if @option{pgc} and @option{pg} are not set.
> +Default is 0 (auto), which currently only selects the first available title (title 1)
> +and notifies the user about the implications.
> +
> +@item chapter_start
> +The chapter, or PTT (part-of-title), number to start at. Default is 1.
> +
> +@item chapter_end
> +The chapter, or PTT (part-of-title), number to end at. Default is 0,
> +which is a special value to signal end at the last possible chapter.
> +
> +@item angle
> +The video angle number, referring to what is essentially an additional
> +video stream that is composed from alternate frames interleaved in the VOBs.
> +Default is 1.
> +
> +@item region
> +The region code to use for playback. Some discs may use this to default playback
> +at a particular angle in different regions. This option will not affect the region code
> +of a real DVD drive, if used as an input. Default is 0, "world".
> +
> +@item pgc
> +The entry PGC to start playback, in conjunction with @option{pg}.
> +Alternative to setting @option{title}.

> +Chapter markers not supported at this time.

nit: are not supported ...

> +Default is 0, automatically resolve from value of @option{title}.
> +
> +@item pg
> +The entry PG to start playback, in conjunction with @option{pgc}.
> +Alternative to setting @option{title}.
> +Chapter markers not supported at this time.

are not

> +Default is 0, automatically resolve from value of @option{title}.
> +
> +@item preindex
> +Enable this to have accurate chapter (PTT) markers and duration measurement,
> +which requires a slow second pass read in order to index the chapter

> +timestamps from NAV packets. This is non-ideal extra work for physical DVD drives.

note: if this is non-idela for physical DVD drivers, what's the
recommended use case?

> +Not compatible with @option{pgc} and @option{pg}.
> +Default is 0, false.
> +
> +@item trim
> +Skip padding cells (i.e. cells shorter than 1 second) from the beginning.
> +There exist many discs with filler segments at the beginning of the PGC,
> +often with junk data intended for controlling a real DVD player's
> +buffering speed and with no other material data value.
> +Default is 1, true.
> +
> +@end table
> +
> +@subsection Examples
> +
> +@itemize
> +@item
> +Open title 3 from a given DVD structure:
> +@example
> +ffmpeg -f dvdvideo -title 3 -i <path to DVD> ...
> +@end example
> +
> +@item
> +Open chapters 3-6 from title 1 from a given DVD structure:
> +@example
> +ffmpeg -f dvdvideo -chapter_start 3 -chapter_end 6 -title 1 -i <path to DVD> ...
> +@end example
> +
> +@item
> +Open only chapter 5 from title 1 from a given DVD structure:
> +@example
> +ffmpeg -f dvdvideo -chapter_start 5 -chapter_end 5 -title 1 -i <path to DVD> ...
> +@end example
> +@end itemize
> +
>  @section ea
>  
>  Electronic Arts Multimedia format demuxer.
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index 05b9b8a115..df69734877 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -192,6 +192,7 @@ OBJS-$(CONFIG_DTS_MUXER)                 += rawenc.o
>  OBJS-$(CONFIG_DV_MUXER)                  += dvenc.o
>  OBJS-$(CONFIG_DVBSUB_DEMUXER)            += dvbsub.o rawdec.o
>  OBJS-$(CONFIG_DVBTXT_DEMUXER)            += dvbtxt.o rawdec.o
> +OBJS-$(CONFIG_DVDVIDEO_DEMUXER)          += dvdvideodec.o
>  OBJS-$(CONFIG_DXA_DEMUXER)               += dxa.o
>  OBJS-$(CONFIG_EA_CDATA_DEMUXER)          += eacdata.o
>  OBJS-$(CONFIG_EA_DEMUXER)                += electronicarts.o
> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> index b04b43cab3..3e905c23f8 100644
> --- a/libavformat/allformats.c
> +++ b/libavformat/allformats.c
> @@ -150,6 +150,7 @@ extern const AVInputFormat  ff_dv_demuxer;
>  extern const FFOutputFormat ff_dv_muxer;
>  extern const AVInputFormat  ff_dvbsub_demuxer;
>  extern const AVInputFormat  ff_dvbtxt_demuxer;
> +extern const AVInputFormat  ff_dvdvideo_demuxer;
>  extern const AVInputFormat  ff_dxa_demuxer;
>  extern const AVInputFormat  ff_ea_demuxer;
>  extern const AVInputFormat  ff_ea_cdata_demuxer;
> diff --git a/libavformat/dvdvideodec.c b/libavformat/dvdvideodec.c
> new file mode 100644
> index 0000000000..2e363a4a22
> --- /dev/null
> +++ b/libavformat/dvdvideodec.c
> @@ -0,0 +1,1410 @@
> +/*
> + * DVD-Video demuxer, powered by libdvdnav and libdvdread
> + *
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * FFmpeg is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with FFmpeg; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +/*
> + * See doc/demuxers.texi for a high-level overview.
> + *
> + * The tactical approach is as follows:
> + * 1) Open the volume with dvdread
> + * 2) Analyze the user-requested title and PGC coordinates in the IFO structures
> + * 3) Request playback at the coordinates and chosen angle with dvdnav
> + * 5) Begin the playback (reading and demuxing) of MPEG-PS blocks
> + * 6) End playback if navigation goes backwards, to a menu, or a different PGC or angle
> + * 7) Close the dvdnav VM, and free dvdread's IFO structures
> + */
> +
> +#include <dvdnav/dvdnav.h>
> +#include <dvdread/dvd_reader.h>
> +#include <dvdread/ifo_read.h>
> +#include <dvdread/ifo_types.h>
> +#include <dvdread/nav_read.h>
> +
> +#include "libavcodec/avcodec.h"
> +#include "libavutil/avstring.h"
> +#include "libavutil/avutil.h"
> +#include "libavutil/intreadwrite.h"
> +#include "libavutil/mem.h"
> +#include "libavutil/opt.h"
> +#include "libavutil/samplefmt.h"
> +#include "libavutil/time.h"
> +#include "libavutil/timestamp.h"
> +
> +#include "avformat.h"
> +#include "avio_internal.h"
> +#include "avlanguage.h"
> +#include "demux.h"
> +#include "internal.h"
> +#include "url.h"
> +
> +#define DVDVIDEO_MAX_PS_SEARCH_BLOCKS                   128
> +#define DVDVIDEO_BLOCK_SIZE                             2048
> +#define DVDVIDEO_TIME_BASE_Q                            (AVRational) { 1, 90000 }
> +#define DVDVIDEO_PTS_WRAP_BITS                          64 /* VOBUs use 32 (PES allows 33) */
> +#define DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE                1024
> +
> +enum DVDVideoSubpictureViewport {
> +    DVDVIDEO_SUBP_VIEWPORT_FULLSCREEN,
> +    DVDVIDEO_SUBP_VIEWPORT_WIDESCREEN,
> +    DVDVIDEO_SUBP_VIEWPORT_LETTERBOX,
> +    DVDVIDEO_SUBP_VIEWPORT_PANSCAN
> +};
> +const char* VIEWPORT_LABELS[4] = { "Fullscreen", "Widescreen", "Letterbox", "Pan and Scan" };
> +
> +typedef struct DVDVideoVTSVideoStreamEntry {
> +    int startcode;
> +    enum AVCodecID codec_id;
> +    int width;
> +    int height;
> +    AVRational dar;
> +    AVRational framerate;
> +    int has_cc;
> +} DVDVideoVTSVideoStreamEntry;
> +
> +typedef struct DVDVideoPGCAudioStreamEntry {
> +    int startcode;
> +    enum AVCodecID codec_id;
> +    int sample_fmt;
> +    int sample_rate;
> +    int bit_depth;
> +    int nb_channels;
> +    AVChannelLayout ch_layout;
> +    int disposition;
> +    char *lang_iso;
> +} DVDVideoPGCAudioStreamEntry;
> +
> +typedef struct DVDVideoPGCSubtitleStreamEntry {
> +    int startcode;
> +    int disposition;
> +    char *lang_iso;
> +    enum DVDVideoSubpictureViewport viewport;
> +} DVDVideoPGCSubtitleStreamEntry;
> +
> +typedef struct DVDVideoPlaybackState {
> +    int                         celln;              /* ID of the active cell */
> +    int                         entry_pgn;          /* ID of the PG we are starting in */
> +    int                         in_pgc;             /* if our navigator is in the PGC */
> +    int                         in_ps;              /* if our navigator is in the program stream */
> +    int                         in_vts;             /* if our navigator is in the VTS */
> +    int64_t                     nav_pts;            /* PTS according to IFO, not frame-accurate */
> +    int                         nb_vobus_played;    /* number of VOBUs played back so far */
> +    uint64_t                    pgc_duration_est;   /* estimated duration as reported by IFO */
> +    uint64_t                    pgc_elapsed;        /* the elapsed time of the PGC, cell-relative */
> +    int                         pgc_nb_pg_est;      /* number of PGs as reported by IFOs */
> +    int                         pgcn;               /* ID of the PGC we are playing */
> +    int                         pgn;                /* ID of the PG we are in now */
> +    int                         ptt;                /* ID of the chapter we are in now */
> +    int64_t                     ts_offset;          /* PTS discontinuity offset (ex. VOB change) */
> +    uint32_t                    vobu_duration;      /* duration of the current VOBU */
> +    uint32_t                    vobu_e_ptm;         /* end PTS of the current VOBU */
> +    int                         vtsn;               /* ID of the active VTS (video title set) */
> +    uint64_t                    *pgc_pg_times_est;  /* PG start times as reported by IFO */
> +    pgc_t                       *pgc;               /* handle to the active PGC */
> +    dvdnav_t                    *dvdnav;            /* handle to libdvdnav */
> +} DVDVideoPlaybackState;
> +
> +typedef struct DVDVideoDemuxContext {
> +    const AVClass               *class;
> +
> +    /* options */
> +    int                         opt_title;          /* the user-provided title number (1-indexed) */
> +    int                         opt_chapter_start;  /* the user-provided entry PTT (1-indexed) */
> +    int                         opt_chapter_end;    /* the user-provided exit PTT (0 for last) */
> +    int                         opt_pgc;            /* the user-provided PGC number (1-indexed) */
> +    int                         opt_pg;             /* the user-provided PG number (1-indexed) */
> +    int                         opt_angle;          /* the user-provided angle number (1-indexed) */
> +    int                         opt_region;         /* the user-provided region digit */
> +    int                         opt_preindex;       /* pre-indexing mode (2-pass read) */
> +    int                         opt_trim;           /* trim padding cells at beginning and end */
> +
> +    /* subdemux */
> +    const AVInputFormat         *mpeg_fmt;          /* inner MPEG-PS (VOB) demuxer */
> +    AVFormatContext             *mpeg_ctx;          /* context for inner demuxer */
> +    uint8_t                     *mpeg_buf;          /* buffer for inner demuxer */
> +    FFIOContext                 mpeg_pb;            /* buffer context for inner demuxer */
> +
> +    /* volume */
> +    dvd_reader_t                *dvdread;           /* handle to libdvdread */
> +    ifo_handle_t                *vmg_ifo;           /* handle to the VMG (VIDEO_TS.IFO) */
> +    ifo_handle_t                *vts_ifo;           /* handle to the active VTS (VTS_nn_n.IFO) */
> +
> +    /* playback control */
> +    int                         play_end;           /* signal EOF to the parent demuxer */
> +    DVDVideoPlaybackState       play_state;         /* the active playback state */
> +    int                         play_started;       /* signal that playback has started */
> +    int                         play_seg_started;   /* signal that segment has started */
> +    int64_t                     first_pts;          /* the starting PTS offset of the PGC */
> +    uint64_t                    duration_ptm;       /* total duration in DVD MPEG timebase */
> +} DVDVideoDemuxContext;
> +
> +static void dvdvideo_libdvdread_log(void *opaque, dvd_logger_level_t level,
> +                                    const char *msg, va_list msg_va)
> +{
> +    AVFormatContext *s = opaque;
> +    int lavu_level;
> +
> +    char msg_buf[DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE] = {0};
> +    vsnprintf(msg_buf, DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE, msg, msg_va);
> +
> +    switch (level) {
> +        case DVD_LOGGER_LEVEL_ERROR:
> +            lavu_level = AV_LOG_ERROR;
> +            break;
> +        case DVD_LOGGER_LEVEL_WARN:
> +            lavu_level = AV_LOG_WARNING;
> +            break;
> +        /* dvdread's info messages are relatively very verbose, muffle them as debug */
> +        case DVD_LOGGER_LEVEL_INFO:
> +        case DVD_LOGGER_LEVEL_DEBUG:
> +        default:
> +            lavu_level = AV_LOG_DEBUG;
> +    }
> +
> +    av_log(s, lavu_level, "libdvdread: %s\n", msg_buf);
> +}
> +
> +static void dvdvideo_libdvdnav_log(void *opaque, dvdnav_logger_level_t level,
> +                                   const char *msg, va_list msg_va)
> +{
> +    AVFormatContext *s = opaque;
> +    int lavu_level;
> +
> +    char msg_buf[DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE] = {0};
> +    vsnprintf(msg_buf, DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE, msg, msg_va);
> +
> +    switch (level) {
> +        case DVDNAV_LOGGER_LEVEL_ERROR:
> +            lavu_level = AV_LOG_ERROR;
> +            break;
> +        case DVDNAV_LOGGER_LEVEL_WARN:
> +            /* some discs have invalid language codes set for their menus, muffle the noise */
> +            lavu_level = av_strstart(msg, "Language", NULL) ? AV_LOG_DEBUG : AV_LOG_WARNING;
> +            break;
> +        /* dvdnav's info messages are relatively very verbose, muffle them as debug */
> +        case DVDNAV_LOGGER_LEVEL_INFO:
> +        case DVDNAV_LOGGER_LEVEL_DEBUG:
> +        default:
> +            lavu_level = AV_LOG_DEBUG;
> +    }
> +
> +    av_log(s, lavu_level, "libdvdnav: %s\n", msg_buf);
> +}
> +
> +static void dvdvideo_ifo_close(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    if (c->vts_ifo)
> +        ifoClose(c->vts_ifo);
> +
> +    if (c->vmg_ifo)
> +        ifoClose(c->vmg_ifo);
> +
> +    if (c->dvdread)
> +        DVDClose(c->dvdread);
> +}
> +
> +static int dvdvideo_ifo_open(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    dvd_logger_cb dvdread_log_cb;
> +    title_info_t title_info;
> +
> +    dvdread_log_cb = (dvd_logger_cb) { .pf_log = dvdvideo_libdvdread_log };
> +    c->dvdread = DVDOpen2(s, &dvdread_log_cb, s->url);
> +
> +    if (!c->dvdread) {
> +        av_log(s, AV_LOG_ERROR, "Unable to open the DVD-Video structure\n");
> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    if (!(c->vmg_ifo = ifoOpen(c->dvdread, 0))) {
> +        av_log(s, AV_LOG_ERROR, "Unable to open the VMG (VIDEO_TS.IFO)\n");
> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    if (c->opt_title > c->vmg_ifo->tt_srpt->nr_of_srpts) {
> +        av_log(s, AV_LOG_ERROR, "Title %d not found\n", c->opt_title);
> +
> +        return AVERROR_STREAM_NOT_FOUND;
> +    }
> +
> +    title_info = c->vmg_ifo->tt_srpt->title[c->opt_title - 1];
> +    if (c->opt_angle > title_info.nr_of_angles) {
> +        av_log(s, AV_LOG_ERROR, "Angle %d not found\n", c->opt_angle);
> +
> +        return AVERROR_STREAM_NOT_FOUND;
> +    }
> +
> +    if (title_info.nr_of_ptts < 1) {
> +        av_log(s, AV_LOG_ERROR, "Title %d has invalid headers (no parts)\n", c->opt_title);
> +
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    if (c->opt_chapter_start > title_info.nr_of_ptts
> +            || (c->opt_chapter_end > 0 && c->opt_chapter_end > title_info.nr_of_ptts)) {
> +        av_log(s, AV_LOG_ERROR, "Chapter (PTT) range [%d, %d] is invalid\n",
> +                                c->opt_chapter_start, c->opt_chapter_end);
> +
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    if (!(c->vts_ifo = ifoOpen(c->dvdread, title_info.title_set_nr))) {
> +        av_log(s, AV_LOG_ERROR, "Unable to process the VTS IFO structure\n");
> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    if (title_info.vts_ttn < 1
> +            || title_info.vts_ttn > 99
> +            || title_info.vts_ttn > c->vts_ifo->vts_ptt_srpt->nr_of_srpts
> +            || c->vts_ifo->vtsi_mat->nr_of_vts_audio_streams > 8
> +            || c->vts_ifo->vtsi_mat->nr_of_vts_subp_streams > 32) {
> +        av_log(s, AV_LOG_ERROR, "Title %d has invalid headers in VTS\n", c->opt_title);
> +
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    return 0;
> +}
> +
> +static void dvdvideo_play_close(AVFormatContext *s, DVDVideoPlaybackState *state)
> +{
> +    if (!state->dvdnav)
> +        return;
> +
> +    /* not allocated by av_malloc() */
> +    if (state->pgc_pg_times_est)
> +        free(state->pgc_pg_times_est);
> +

> +    if (dvdnav_close(state->dvdnav) < 0)
> +        av_log(s, AV_LOG_ERROR, "Unable to cleanly close dvdnav\n");

nit: in case this has consquence, you might print the error code in
the log

> +}
> +
> +static int dvdvideo_play_open(AVFormatContext *s, DVDVideoPlaybackState *state)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret = 0;
> +    dvdnav_logger_cb dvdnav_log_cb;
> +    dvdnav_status_t dvdnav_open_status;
> +    int cur_title, cur_pgcn, cur_pgn;
> +    pgc_t *pgc;
> +
> +    int32_t disc_region_mask;
> +    int32_t player_region_mask;
> +
> +    dvdnav_log_cb = (dvdnav_logger_cb) { .pf_log = dvdvideo_libdvdnav_log };
> +    dvdnav_open_status = dvdnav_open2(&state->dvdnav, s, &dvdnav_log_cb, s->url);
> +

> +    if (!state->dvdnav
> +            || dvdnav_open_status != DVDNAV_STATUS_OK
> +            || dvdnav_set_readahead_flag(state->dvdnav, 0) != DVDNAV_STATUS_OK
> +            || dvdnav_set_PGC_positioning_flag(state->dvdnav, 1) != DVDNAV_STATUS_OK
> +            || dvdnav_get_region_mask(state->dvdnav, &disc_region_mask) != DVDNAV_STATUS_OK) {

nit+: here and below, weird style

usually || is put at the EOL and conditions are aligned, as in

if (foo ||
    bar ||
    baz) {
    ...
}

> +        av_log(s, AV_LOG_ERROR, "Unable to open the DVD for playback\n");
> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    player_region_mask = c->opt_region > 0 ? (1 << (c->opt_region - 1)) : disc_region_mask;
> +    if (dvdnav_set_region_mask(state->dvdnav, player_region_mask) != DVDNAV_STATUS_OK) {
> +        av_log(s, AV_LOG_ERROR, "Unable to set the playback region code %d\n", c->opt_region);
> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    if (c->opt_pgc > 0 && c->opt_pg > 0) {
> +        if (dvdnav_program_play(state->dvdnav, c->opt_title,
> +                                c->opt_pgc, c->opt_pg) != DVDNAV_STATUS_OK) {
> +            av_log(s, AV_LOG_ERROR, "Unable to start playback at title %d, PGC %d, PG %d\n",
> +                                    c->opt_title, c->opt_pgc, c->opt_pg);
> +
> +            return AVERROR_EXTERNAL;
> +        }
> +
> +        state->pgcn = c->opt_pgc;
> +        state->entry_pgn = c->opt_pg;
> +    } else {
> +        if (dvdnav_part_play(state->dvdnav, c->opt_title, c->opt_chapter_start) != DVDNAV_STATUS_OK
> +                || dvdnav_current_title_program(state->dvdnav, &cur_title,
> +                                                &cur_pgcn, &cur_pgn) != DVDNAV_STATUS_OK) {
> +            av_log(s, AV_LOG_ERROR, "Unable to start playback at title %d, chapter (PTT) %d\n",
> +                                    c->opt_title, c->opt_chapter_start);
> +
> +            return AVERROR_EXTERNAL;
> +        }
> +
> +        state->pgcn = cur_pgcn;
> +        state->entry_pgn = cur_pgn;
> +    }
> +
> +    pgc = c->vts_ifo->vts_pgcit->pgci_srp[state->pgcn - 1].pgc;
> +
> +    if (pgc->pg_playback_mode != 0) {
> +        av_log(s, AV_LOG_ERROR, "Non-sequential PGCs, such as shuffles, are not supported\n");
> +
> +        return AVERROR_PATCHWELCOME;
> +    }
> +
> +    if (dvdnav_angle_change(state->dvdnav, c->opt_angle) != DVDNAV_STATUS_OK) {

> +        av_log(s, AV_LOG_ERROR, "Unable to start playback at the given angle\n");

nit: you might mention the failing angle here

> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    /* dvdnav_describe_title_chapters() performs several safety checks on the title structure */
> +    /* take advantage of this side effect to ensure a safe navigation path */
> +    state->pgc_nb_pg_est = dvdnav_describe_title_chapters(state->dvdnav, c->opt_title,
> +                                                          &state->pgc_pg_times_est,
> +                                                          &state->pgc_duration_est);
> +    if (!state->pgc_nb_pg_est) {
> +        av_log(s, AV_LOG_ERROR, "Unable to validate title structure\n");
> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    state->nav_pts = dvdnav_get_current_time(state->dvdnav);
> +    state->vtsn = c->vmg_ifo->tt_srpt->title[c->opt_title - 1].title_set_nr;
> +
> +    state->pgc = pgc;
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_play_is_cell_promising(AVFormatContext *s, DVDVideoPlaybackState *state,
> +                                           int celln)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +    dvd_time_t cell_duration;
> +
> +    if (!c->opt_trim)
> +        return 1;
> +
> +    cell_duration = state->pgc->cell_playback[celln - 1].playback_time;
> +
> +    return cell_duration.second >= 1 || cell_duration.minute >= 1 || cell_duration.hour >= 1;
> +}
> +
> +static int dvdvideo_play_next_ps_block(AVFormatContext *s, DVDVideoPlaybackState *state,
> +                                       uint8_t *buf, int buf_size,
> +                                       int *p_nav_event,
> +                                       void (*flush_cb)(AVFormatContext *s))
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    uint8_t nav_buf[DVDVIDEO_BLOCK_SIZE] = {0};
> +    int nav_event;
> +    int nav_len;
> +
> +    dvdnav_vts_change_event_t *e_vts;
> +    dvdnav_cell_change_event_t *e_cell;
> +    int cur_title, cur_pgcn, cur_pgn, cur_angle, cur_title_unused, cur_ptt, cur_nb_angles;
> +    int is_cell_promising = 0;
> +    pci_t *e_pci;
> +    dsi_t *e_dsi;
> +

> +    if (buf_size != DVDVIDEO_BLOCK_SIZE) {
> +        av_log(s, AV_LOG_ERROR, "Invalid buffer size\n");

you might mention the failing size (Invalid buffer size %d, the DVD block size %d was expected)

> +
> +        return AVERROR(ENOMEM);

Not sure this is the correct error (it's not an allocation error)
maybe more invaliddata or EINVAL.

> +    }
> +
> +    for (int i = 0; i < DVDVIDEO_MAX_PS_SEARCH_BLOCKS; i++) {
> +        if (ff_check_interrupt(&s->interrupt_callback))
> +            return AVERROR_EXIT;
> +
> +        if (dvdnav_get_next_block(state->dvdnav, nav_buf, &nav_event, &nav_len) != DVDNAV_STATUS_OK) {
> +            av_log(s, AV_LOG_ERROR, "Unable to read next block of PGC\n");
> +
> +            return AVERROR_INVALIDDATA;
> +        }
> +
> +        /* some discs follow NOPs with a premature stop event */
> +        if (nav_event == DVDNAV_STOP)
> +            return AVERROR_EOF;
> +
> +        if (nav_len > DVDVIDEO_BLOCK_SIZE) {
> +            av_log(s, AV_LOG_ERROR, "Invalid block size\n");
> +
> +            return AVERROR_INVALIDDATA;
> +        }
> +
> +        if (dvdnav_current_title_info(state->dvdnav, &cur_title,
> +                                      &cur_ptt) != DVDNAV_STATUS_OK) {
> +            av_log(s, AV_LOG_ERROR, "Unable to validate title coordinates\n");
> +
> +            return AVERROR_INVALIDDATA;
> +        }
> +
> +        /* we somehow navigated to a menu */
> +        if (cur_title == 0 || !dvdnav_is_domain_vts(state->dvdnav))
> +            return AVERROR_EOF;
> +
> +        if (dvdnav_current_title_program(state->dvdnav, &cur_title_unused,
> +                                         &cur_pgcn, &cur_pgn) != DVDNAV_STATUS_OK) {
> +            av_log(s, AV_LOG_ERROR, "Unable to validate PGC coordinates\n");
> +
> +            return AVERROR_INVALIDDATA;
> +        }
> +
> +        /* we somehow left the PGC */
> +        if (state->in_pgc && cur_pgcn != state->pgcn)
> +            return AVERROR_EOF;
> +
> +        if (dvdnav_get_angle_info(state->dvdnav, &cur_angle, &cur_nb_angles) != DVDNAV_STATUS_OK) {
> +            av_log(s, AV_LOG_ERROR, "Unable to validate angle coordinates\n");
> +
> +            return AVERROR_INVALIDDATA;
> +        }
> +
> +        av_log(s, nav_event == DVDNAV_BLOCK_OK ? AV_LOG_TRACE : AV_LOG_DEBUG,

> +                                "new block: i=%d nav_event=%d nav_len=%d cur_title=%d "
> +                                "cur_ptt=%d cur_angle=%d cur_celln=%d cur_pgcn=%d cur_pgn=%d "
> +                                "play_in_vts=%d play_in_pgc=%d play_in_ps=%d\n",
> +                                i, nav_event, nav_len, cur_title,
> +                                cur_ptt, cur_angle, state->celln, cur_pgcn, cur_pgn,
> +                                state->in_vts, state->in_pgc, state->in_ps);

nit: weird indent

> +
> +        switch (nav_event) {
> +            case DVDNAV_VTS_CHANGE:
> +                if (state->in_vts)
> +                    return AVERROR_EOF;
> +
> +                e_vts = (dvdnav_vts_change_event_t *) nav_buf;
> +
> +                if (e_vts->new_vtsN == state->vtsn && e_vts->new_domain == DVD_DOMAIN_VTSTitle)
> +                    state->in_vts = 1;
> +
> +                continue;
> +            case DVDNAV_CELL_CHANGE:
> +                if (!state->in_vts)
> +                    continue;
> +
> +                e_cell = (dvdnav_cell_change_event_t *) nav_buf;
> +                is_cell_promising = dvdvideo_play_is_cell_promising(s, state, e_cell->cellN);
> +
> +                av_log(s, AV_LOG_DEBUG, "new cell: prev=%d new=%d promising=%d\n",
> +                                        state->celln, e_cell->cellN, is_cell_promising);
> +
> +                if (!state->in_ps && !state->in_pgc) {

> +                    if (cur_title == c->opt_title && cur_ptt == c->opt_chapter_start
> +                            && cur_pgcn == state->pgcn && cur_pgn == state->entry_pgn
> +                            && is_cell_promising) {

nit: weird align

> +                        state->in_pgc = 1;
> +                    }
> +
> +                    if (c->opt_trim && !is_cell_promising)
> +                        av_log(s, AV_LOG_INFO, "Skipping padding cell #%d\n", e_cell->cellN);
> +                } else if (state->celln >= e_cell->cellN || state->pgn > cur_pgn) {
> +                    return AVERROR_EOF;
> +                }
> +
> +                state->celln = e_cell->cellN;
> +                state->ptt = cur_ptt;
> +                state->pgn = cur_pgn;
> +
> +                continue;
> +            case DVDNAV_NAV_PACKET:
> +                if (!state->in_pgc)
> +                    continue;
> +
> +                if ((state->ptt > 0 && state->ptt > cur_ptt)
> +                        || (c->opt_chapter_end > 0 && cur_ptt > c->opt_chapter_end)) {
> +                    return AVERROR_EOF;
> +                }
> +
> +                e_pci = dvdnav_get_current_nav_pci(state->dvdnav);
> +                e_dsi = dvdnav_get_current_nav_dsi(state->dvdnav);
> +
> +                if (e_pci == NULL || e_dsi == NULL
> +                                  || e_pci->pci_gi.vobu_s_ptm > e_pci->pci_gi.vobu_e_ptm) {
> +                    av_log(s, AV_LOG_ERROR, "Invalid NAV packet\n");
> +
> +                    return AVERROR_INVALIDDATA;
> +                }
> +
> +                state->vobu_duration = e_pci->pci_gi.vobu_e_ptm - e_pci->pci_gi.vobu_s_ptm;
> +                state->pgc_elapsed += state->vobu_duration;
> +                state->nav_pts = dvdnav_get_current_time(state->dvdnav);
> +                state->ptt = cur_ptt;
> +                state->pgn = cur_pgn;
> +                state->nb_vobus_played++;
> +
> +                av_log(s, AV_LOG_DEBUG, "NAV pack: s_ptm=%d e_ptm=%d "
> +                                        "scr=%d lbn=%d vobu_duration=%d nav_pts=%ld\n",
> +                            e_pci->pci_gi.vobu_s_ptm, e_pci->pci_gi.vobu_e_ptm,
> +                            e_dsi->dsi_gi.nv_pck_scr,
> +                            e_pci->pci_gi.nv_pck_lbn, state->vobu_duration, state->nav_pts);
> +
> +                if (!state->in_ps) {
> +                    av_log(s, AV_LOG_DEBUG, "navigation: locked to program stream\n");
> +
> +                    state->in_ps = 1;
> +                } else {
> +                    if (state->vobu_e_ptm != e_pci->pci_gi.vobu_s_ptm) {
> +                        if (flush_cb)
> +                            flush_cb(s);
> +
> +                        state->ts_offset += state->vobu_e_ptm - e_pci->pci_gi.vobu_s_ptm;
> +                    }
> +                }
> +
> +                state->vobu_e_ptm = e_pci->pci_gi.vobu_e_ptm;
> +
> +                (*p_nav_event) = nav_event;
> +
> +                return nav_len;
> +            case DVDNAV_BLOCK_OK:
> +                if (!state->in_ps) {
> +                    if (state->in_pgc)
> +                        i = 0; /* necessary in case we are skipping junk cells at the beginning */
> +                    continue;
> +                }
> +
> +                if (nav_len != DVDVIDEO_BLOCK_SIZE) {
> +                    av_log(s, AV_LOG_ERROR, "Invalid block size\n");
> +
> +                    return AVERROR_INVALIDDATA;
> +                }
> +
> +                if (cur_angle != c->opt_angle) {
> +                    av_log(s, AV_LOG_ERROR, "Unexpected angle change\n");
> +
> +                    return AVERROR_INPUT_CHANGED;
> +                }
> +
> +                memcpy(buf, &nav_buf, nav_len);
> +
> +                /* in case NAV packet is missed */
> +                state->ptt = cur_ptt;
> +                state->pgn = cur_pgn;
> +
> +                (*p_nav_event) = nav_event;
> +
> +                return nav_len;
> +            case DVDNAV_STILL_FRAME:
> +            case DVDNAV_WAIT:
> +            case DVDNAV_HOP_CHANNEL:
> +            case DVDNAV_HIGHLIGHT:
> +                if (state->in_ps)
> +                    return AVERROR_EOF;
> +
> +                if (nav_event == DVDNAV_STILL_FRAME)
> +                    dvdnav_still_skip(state->dvdnav);
> +                if (nav_event == DVDNAV_WAIT)
> +                    dvdnav_wait_skip(state->dvdnav);
> +
> +                continue;
> +            case DVDNAV_STOP:
> +                return AVERROR_EOF;
> +            default:
> +                continue;
> +        }
> +    }
> +
> +    av_log(s, AV_LOG_ERROR, "Unable to find next program stream block\n");
> +
> +    return AVERROR_INVALIDDATA;
> +}
> +
> +static int dvdvideo_pgc_preindex(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret = 0, interrupt = 0;
> +    int nb_chapters = 0, last_ptt = c->opt_chapter_start;
> +    uint64_t cur_chapter_offset = 0, cur_chapter_duration = 0;
> +    DVDVideoPlaybackState *state;
> +
> +    uint8_t nav_buf[DVDVIDEO_BLOCK_SIZE];
> +    int nav_event;
> +
> +    if (c->opt_chapter_start == c->opt_chapter_end)
> +        return 0;
> +
> +    av_log(s, AV_LOG_INFO,
> +           "Indexing chapter markers, this will take a long time. Please wait...\n");
> +
> +    state = av_mallocz(sizeof(DVDVideoPlaybackState));
> +    if ((ret = dvdvideo_play_open(s, state)) < 0) {
> +        av_freep(&state);
> +        return ret;
> +    }
> +
> +    while (!(interrupt = ff_check_interrupt(&s->interrupt_callback))) {
> +        ret = dvdvideo_play_next_ps_block(s, state, nav_buf, DVDVIDEO_BLOCK_SIZE,
> +                                          &nav_event, NULL);
> +        if (ret < 0 && ret != AVERROR_EOF)
> +            goto end_free;
> +
> +        if (nav_event != DVDNAV_NAV_PACKET && ret != AVERROR_EOF)
> +            continue;
> +
> +        if (state->ptt == last_ptt) {
> +            cur_chapter_duration += state->vobu_duration;
> +            /* ensure we add the last chapter */
> +            if (ret != AVERROR_EOF)
> +                continue;
> +        }
> +

> +        if (!avpriv_new_chapter(s, nb_chapters, DVDVIDEO_TIME_BASE_Q, cur_chapter_offset,
> +                                cur_chapter_offset + cur_chapter_duration, NULL)) {
> +            av_log(s, AV_LOG_ERROR, "Unable to allocate chapter\n");

ret is not set in this case

> +
> +            goto end_free;
> +        }
> +
> +        nb_chapters++;
> +        cur_chapter_offset += cur_chapter_duration;
> +        cur_chapter_duration = state->vobu_duration;
> +        last_ptt = state->ptt;
> +
> +        if (ret == AVERROR_EOF)
> +            break;
> +    }
> +
> +    if (interrupt) {
> +        ret = AVERROR_EXIT;
> +        goto end_free;
> +    }
> +
> +    if (ret < 0 && ret != AVERROR_EOF)
> +        goto end_free;
> +
> +    s->duration = av_rescale_q(state->pgc_elapsed, DVDVIDEO_TIME_BASE_Q, AV_TIME_BASE_Q);
> +    c->duration_ptm = state->pgc_elapsed;
> +
> +    av_log(s, AV_LOG_INFO, "Chapter marker indexing complete\n");
> +    ret = 0;
> +
> +end_free:
> +    dvdvideo_play_close(s, state);
> +    av_freep(&state);
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_pgc_chapters_setup(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    uint64_t time_prev = 0;
> +    int64_t total_duration = 0;
> +
> +    int chapter_start = c->opt_chapter_start - 1;
> +    int chapter_end = c->opt_chapter_end > 0 ? c->opt_chapter_end : c->play_state.pgc_nb_pg_est - 1;
> +
> +    if (chapter_start == chapter_end || c->play_state.pgc_nb_pg_est == 1) {
> +        s->duration = av_rescale_q(c->play_state.pgc_duration_est,
> +                                   DVDVIDEO_TIME_BASE_Q, AV_TIME_BASE_Q);
> +        return 0;
> +    }
> +
> +    for (int i = chapter_start; i < chapter_end; i++) {
> +        uint64_t time_effective = c->play_state.pgc_pg_times_est[i] - c->play_state.nav_pts;
> +
> +        if (!avpriv_new_chapter(s, i, DVDVIDEO_TIME_BASE_Q, time_prev,
> +                                time_effective, NULL)) {
> +            av_log(s, AV_LOG_ERROR, "Unable to allocate chapter\n");
> +            return AVERROR(ENOMEM);
> +        }
> +
> +        time_prev = time_effective;
> +        total_duration = time_effective;
> +    }
> +
> +    if (c->opt_chapter_start == 1 && c->opt_chapter_end == 0)
> +        s->duration = av_rescale_q(c->play_state.pgc_duration_est,
> +                                   DVDVIDEO_TIME_BASE_Q, AV_TIME_BASE_Q);
> +    else
> +        s->duration = av_rescale_q(total_duration,
> +                                   DVDVIDEO_TIME_BASE_Q, AV_TIME_BASE_Q);
> +
> +    return 0;
> +}
> +
> +static int dvdvideo_video_stream_analyze(AVFormatContext *s, video_attr_t video_attr,
> +                                         DVDVideoVTSVideoStreamEntry *entry)
> +{
> +    AVRational framerate;
> +    int height = 0;
> +    int width = 0;
> +    int is_pal = video_attr.video_format == 1;
> +
> +    framerate = is_pal ? (AVRational) { 25, 1 } : (AVRational) { 30000, 1001 };
> +    height = is_pal ? 576 : 480;
> +
> +    if (height > 0) {
> +        switch (video_attr.picture_size) {
> +            case 0: /* D1 */
> +                width = 720;
> +                break;
> +            case 1: /* 4CIF */
> +                width = 704;
> +                break;
> +            case 2: /* Half D1 */
> +                width = 352;
> +                break;
> +            case 3: /* CIF */
> +                width = 352;
> +                height /= 2;
> +                break;
> +        }
> +    }
> +
> +    if (!width || !height) {

> +        av_log(s, AV_LOG_ERROR, "Invalid video dimensions\n");

you might print the actual size to help debug impossible cases

> +
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    entry->startcode = 0x1E0;
> +    entry->codec_id = !video_attr.mpeg_version ? AV_CODEC_ID_MPEG1VIDEO : AV_CODEC_ID_MPEG2VIDEO;
> +    entry->width = width;
> +    entry->height = height;
> +    entry->dar = video_attr.display_aspect_ratio ? (AVRational) { 16, 9 } : (AVRational) { 4, 3 };
> +    entry->framerate = framerate;
> +    entry->has_cc = !is_pal && (video_attr.line21_cc_1 || video_attr.line21_cc_2);
> +
> +    return 0;
> +}
> +
> +static int dvdvideo_video_stream_add(AVFormatContext *s,
> +                                     DVDVideoVTSVideoStreamEntry *entry,
> +                                     enum AVStreamParseType need_parsing)
> +{
> +    AVStream *st;
> +    FFStream *sti;
> +
> +    st = avformat_new_stream(s, NULL);
> +    if (!st)
> +        return AVERROR(ENOMEM);
> +
> +    st->id = entry->startcode;
> +    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
> +    st->codecpar->codec_id = entry->codec_id;
> +    st->codecpar->width = entry->width;
> +    st->codecpar->height = entry->height;
> +    st->codecpar->format = AV_PIX_FMT_YUV420P;
> +    st->codecpar->color_range = AVCOL_RANGE_MPEG;
> +
> +    st->codecpar->framerate = entry->framerate;
> +#if FF_API_R_FRAME_RATE
> +    st->r_frame_rate = entry->framerate;
> +#endif
> +    st->avg_frame_rate = entry->framerate;
> +
> +    sti = ffstream(st);
> +    sti->request_probe = 0;
> +    sti->need_parsing = need_parsing;
> +    sti->display_aspect_ratio = entry->dar;
> +    sti->avctx->framerate = entry->framerate;
> +
> +    if (entry->has_cc)
> +        sti->avctx->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS;
> +
> +    avpriv_set_pts_info(st, DVDVIDEO_PTS_WRAP_BITS,
> +                        DVDVIDEO_TIME_BASE_Q.num, DVDVIDEO_TIME_BASE_Q.den);
> +
> +    return 0;
> +}
> +
> +static int dvdvideo_video_stream_setup(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    DVDVideoVTSVideoStreamEntry *entry = NULL;
> +    int ret = 0;
> +

> +    entry = av_mallocz(sizeof(DVDVideoVTSVideoStreamEntry));

you might check for failure

> +
> +    if ((ret = dvdvideo_video_stream_analyze(s, c->vts_ifo->vtsi_mat->vts_video_attr, entry)) < 0
> +            || (ret = dvdvideo_video_stream_add(c->mpeg_ctx, entry, AVSTREAM_PARSE_FULL)) < 0
> +            || (ret = dvdvideo_video_stream_add(s, entry, AVSTREAM_PARSE_HEADERS)) < 0) {
> +        av_freep(&entry);

> +        av_log(s, AV_LOG_ERROR, "Unable to allocate video stream\n");

misleading error message, I'd say: Unable to add video stream

> +
> +        return ret;
> +    }
> +
> +    av_freep(&entry);
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_audio_stream_analyze(AVFormatContext *s, audio_attr_t audio_attr,
> +                                         uint16_t audio_control, DVDVideoPGCAudioStreamEntry *entry)
> +{
> +    int startcode = 0;
> +    enum AVCodecID codec_id = AV_CODEC_ID_NONE;
> +    int sample_fmt = AV_SAMPLE_FMT_NONE;
> +    int sample_rate = 0;
> +    int bit_depth = 0;
> +    int nb_channels = 0;
> +    AVChannelLayout ch_layout = (AVChannelLayout) {0};
> +    char lang_dvd[3] = {0};
> +
> +    int position = (audio_control & 0x7F00) >> 8;
> +
> +    /* XXX(PATCHWELCOME): SDDS is not supported due to lack of sample material */
> +    switch (audio_attr.audio_format) {
> +        case 0: /* AC3 */
> +            codec_id = AV_CODEC_ID_AC3;
> +            sample_fmt = AV_SAMPLE_FMT_FLTP;
> +            sample_rate = 48000;
> +            startcode = 0x80 + position;
> +            break;
> +        case 2: /* MP1 */
> +            codec_id = AV_CODEC_ID_MP1;
> +            sample_fmt = audio_attr.quantization ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;
> +            sample_rate = 48000;
> +            bit_depth = audio_attr.quantization ? 20 : 16;
> +            startcode = 0x1C0 + position;
> +            break;
> +        case 3: /* MP2 */
> +            codec_id = AV_CODEC_ID_MP2;
> +            sample_fmt = audio_attr.quantization ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;
> +            sample_rate = 48000;
> +            bit_depth = audio_attr.quantization ? 20 : 16;
> +            startcode = 0x1C0 + position;
> +            break;
> +        case 4: /* DVD PCM */
> +            codec_id = AV_CODEC_ID_PCM_DVD;
> +            sample_fmt = audio_attr.quantization ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;
> +            sample_rate = audio_attr.sample_frequency ? 96000 : 48000;
> +            bit_depth = audio_attr.quantization == 2 ? 24 : (audio_attr.quantization ? 20 : 16);
> +            startcode = 0xA0 + position;
> +            break;
> +        case 6: /* DCA */
> +            codec_id = AV_CODEC_ID_DTS;
> +            sample_fmt = AV_SAMPLE_FMT_FLTP;
> +            sample_rate = 48000;
> +            bit_depth = audio_attr.quantization == 2 ? 24 : (audio_attr.quantization ? 20 : 16);
> +            startcode = 0x88 + position;
> +            break;
> +    }
> +
> +    nb_channels = audio_attr.channels + 1;
> +
> +    if (codec_id == AV_CODEC_ID_NONE
> +            || startcode == 0 || sample_fmt == AV_SAMPLE_FMT_NONE
> +            || sample_rate == 0 || nb_channels == 0) {

> +        av_log(s, AV_LOG_ERROR, "Invalid audio parameters\n");

please provide some context to help debug impossible cases

> +
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    if (nb_channels == 2)
> +        ch_layout = (AVChannelLayout) AV_CHANNEL_LAYOUT_STEREO;
> +    else if (nb_channels == 6)
> +        ch_layout = (AVChannelLayout) AV_CHANNEL_LAYOUT_5POINT1;
> +    else if (nb_channels == 7)
> +        ch_layout = (AVChannelLayout) AV_CHANNEL_LAYOUT_6POINT1;
> +    else if (nb_channels == 8)
> +        ch_layout = (AVChannelLayout) AV_CHANNEL_LAYOUT_7POINT1;
> +
> +    if (audio_attr.code_extension == 2)
> +        entry->disposition |= AV_DISPOSITION_VISUAL_IMPAIRED;
> +    if (audio_attr.code_extension == 3 || audio_attr.code_extension == 4)
> +        entry->disposition |= AV_DISPOSITION_COMMENT;
> +
> +    AV_WB16(lang_dvd, audio_attr.lang_code);
> +
> +    entry->startcode = startcode;
> +    entry->codec_id = codec_id;
> +    entry->sample_rate = sample_rate;
> +    entry->bit_depth = bit_depth;
> +    entry->nb_channels = nb_channels;
> +    entry->ch_layout = ch_layout;
> +    entry->lang_iso = (char *) ff_convert_lang_to(lang_dvd, AV_LANG_ISO639_2_BIBL);
> +
> +    return 0;
> +}
> +
> +static int dvdvideo_audio_stream_add(AVFormatContext *s, DVDVideoPGCAudioStreamEntry *entry,
> +                                     enum AVStreamParseType need_parsing)
> +{
> +    AVStream *st;
> +    FFStream *sti;
> +
> +    st = avformat_new_stream(s, NULL);
> +    if (!st)
> +        return AVERROR(ENOMEM);
> +
> +    st->id = entry->startcode;
> +    st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
> +    st->codecpar->codec_id = entry->codec_id;
> +    st->codecpar->format = entry->sample_fmt;
> +    st->codecpar->sample_rate = entry->sample_rate;
> +    st->codecpar->bits_per_coded_sample = entry->bit_depth;
> +    st->codecpar->bits_per_raw_sample = entry->bit_depth;
> +    st->codecpar->ch_layout = entry->ch_layout;
> +    st->codecpar->ch_layout.nb_channels = entry->nb_channels;
> +    st->disposition = entry->disposition;
> +
> +    if (entry->lang_iso)
> +        av_dict_set(&st->metadata, "language", entry->lang_iso, 0);
> +
> +    sti = ffstream(st);
> +    sti->request_probe = 0;
> +    sti->need_parsing = need_parsing;
> +
> +    avpriv_set_pts_info(st, DVDVIDEO_PTS_WRAP_BITS,
> +                        DVDVIDEO_TIME_BASE_Q.num, DVDVIDEO_TIME_BASE_Q.den);
> +
> +    return 0;
> +}
> +
> +static int dvdvideo_audio_stream_add_all(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret = 0;
> +
> +    for (int i = 0; i < c->vts_ifo->vtsi_mat->nr_of_vts_audio_streams; i++) {
> +        DVDVideoPGCAudioStreamEntry *entry = NULL;
> +
> +        if (!(c->play_state.pgc->audio_control[i] & 0x8000))
> +            continue;
> +
> +        entry = av_mallocz(sizeof(DVDVideoPGCAudioStreamEntry));
> +        if (!entry)
> +            return AVERROR(ENOMEM);
> +
> +        if ((ret = dvdvideo_audio_stream_analyze(s, c->vts_ifo->vtsi_mat->vts_audio_attr[i],
> +                c->play_state.pgc->audio_control[i], entry)) < 0)
> +            goto break_free_and_error;
> +
> +        if (c->vts_ifo->vtsi_mat->vts_audio_attr[i].application_mode == 1)
> +            av_log(s, AV_LOG_WARNING, "Karaoke metadata in stream %d will not be retained\n",
> +                                      entry->startcode);
> +
> +        /* IFO structures can declare duplicate entries for the same startcode */
> +        for (int j = 0; j < s->nb_streams; j++)
> +            if (s->streams[j]->id == entry->startcode)
> +                goto continue_free;
> +
> +        if ((ret = dvdvideo_audio_stream_add(c->mpeg_ctx, entry, AVSTREAM_PARSE_FULL)) < 0
> +                || (ret = dvdvideo_audio_stream_add(s, entry, AVSTREAM_PARSE_HEADERS)) < 0)
> +            goto break_free_and_error;
> +
> +continue_free:
> +        av_freep(&entry);
> +        continue;
> +
> +break_free_and_error:
> +        av_freep(&entry);

> +        av_log(s, AV_LOG_ERROR, "Unable to allocate audio stream\n");

ditto: unable to "add" audio stream?

> +        return ret;
> +    }
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_subp_stream_analyze(AVFormatContext *s, uint32_t offset, subp_attr_t subp_attr,
> +                                        DVDVideoPGCSubtitleStreamEntry *entry)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    char lang_dvd[3] = {0};
> +
> +    entry->startcode = 0x20 + (offset & 0x1F);
> +
> +    if (subp_attr.lang_extension == 9)
> +        entry->disposition |= AV_DISPOSITION_FORCED;
> +
> +    AV_WB16(lang_dvd, subp_attr.lang_code);
> +    entry->lang_iso = (char *) ff_convert_lang_to(lang_dvd, AV_LANG_ISO639_2_BIBL);
> +
> +    return 0;
> +}
> +
> +static int dvdvideo_subp_stream_add(AVFormatContext *s, DVDVideoPGCSubtitleStreamEntry *entry,
> +                                    enum AVStreamParseType need_parsing)
> +{
> +    AVStream *st;
> +    FFStream *sti;
> +    int ret = 0;
> +
> +    st = avformat_new_stream(s, NULL);
> +    if (!st)
> +        return AVERROR(ENOMEM);
> +
> +    st->id = entry->startcode;
> +    st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
> +    st->codecpar->codec_id = AV_CODEC_ID_DVD_SUBTITLE;
> +
> +    if (entry->lang_iso)
> +        av_dict_set(&st->metadata, "language", entry->lang_iso, 0);
> +
> +    av_dict_set(&st->metadata, "VIEWPORT", VIEWPORT_LABELS[entry->viewport], 0);
> +
> +    st->disposition = entry->disposition;
> +
> +    sti = ffstream(st);
> +    sti->request_probe = 0;
> +    sti->need_parsing = need_parsing;
> +
> +    avpriv_set_pts_info(st, DVDVIDEO_PTS_WRAP_BITS,
> +                        DVDVIDEO_TIME_BASE_Q.num, DVDVIDEO_TIME_BASE_Q.den);
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_subp_stream_add_internal(AVFormatContext *s, uint32_t offset,
> +                                             subp_attr_t subp_attr,
> +                                             enum DVDVideoSubpictureViewport viewport)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    DVDVideoPGCSubtitleStreamEntry *entry = NULL;
> +    int ret = 0;
> +

> +    entry = av_mallocz(sizeof(DVDVideoPGCSubtitleStreamEntry));

missing check

> +    entry->viewport = viewport;
> +
> +    if ((ret = dvdvideo_subp_stream_analyze(s, offset, subp_attr, entry)) < 0)
> +        goto end_free_error;
> +
> +    /* IFO structures can declare duplicate entries for the same startcode */
> +    for (int i = 0; i < s->nb_streams; i++)
> +        if (s->streams[i]->id == entry->startcode)
> +            goto end_free;
> +
> +    if ((ret = dvdvideo_subp_stream_add(c->mpeg_ctx, entry, AVSTREAM_PARSE_FULL)) < 0
> +            || (ret = dvdvideo_subp_stream_add(s, entry, AVSTREAM_PARSE_HEADERS)) < 0)
> +        goto end_free_error;
> +
> +    goto end_free;
> +
> +end_free_error:

> +    av_log(s, AV_LOG_ERROR, "Unable to allocate subtitle stream\n");

ditto

> +
> +end_free:
> +    av_freep(&entry);
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_subp_stream_add_all(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    if (!c->vts_ifo->vtsi_mat->nr_of_vts_subp_streams)
> +        return 0;
> +
> +    for (int i = 0; i < c->vts_ifo->vtsi_mat->nr_of_vts_subp_streams; i++) {
> +        int ret = 0;
> +        uint32_t subp_control;
> +        subp_attr_t subp_attr;
> +        video_attr_t video_attr;
> +
> +        subp_control = c->play_state.pgc->subp_control[i];
> +        if (!(subp_control & 0x80000000))
> +            continue;
> +
> +        /* there can be several presentations for one SPU */
> +        /* for now, be flexible with the DAR check due to weird authoring */
> +        video_attr = c->vts_ifo->vtsi_mat->vts_video_attr;
> +        subp_attr = c->vts_ifo->vtsi_mat->vts_subp_attr[i];
> +
> +        /* 4:3 */
> +        if (!video_attr.display_aspect_ratio) {
> +            if ((ret = dvdvideo_subp_stream_add_internal(s, subp_control >> 24, subp_attr,
> +                                                         DVDVIDEO_SUBP_VIEWPORT_FULLSCREEN)) < 0)
> +                return ret;
> +
> +            continue;
> +        }
> +
> +        /* 16:9 */
> +        if ((ret = dvdvideo_subp_stream_add_internal(s, subp_control >> 16, subp_attr,
> +                                                         DVDVIDEO_SUBP_VIEWPORT_WIDESCREEN)) < 0)
> +            return ret;
> +
> +        /* 16:9 letterbox */
> +        if (video_attr.permitted_df == 2 || video_attr.permitted_df == 0)
> +            if ((ret = dvdvideo_subp_stream_add_internal(s, subp_control >> 8, subp_attr,
> +                                                         DVDVIDEO_SUBP_VIEWPORT_LETTERBOX)) < 0)
> +                return ret;
> +
> +        /* 16:9 pan-and-scan */
> +        if (video_attr.permitted_df == 1 || video_attr.permitted_df == 0)
> +            if ((ret = dvdvideo_subp_stream_add_internal(s, subp_control, subp_attr,
> +                                                         DVDVIDEO_SUBP_VIEWPORT_PANSCAN)) < 0)
> +                return ret;
> +    }
> +
> +    return 0;
> +}
> +
> +static void dvdvideo_subdemux_flush(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    if (!c->play_seg_started)
> +        return;
> +
> +    av_log(s, AV_LOG_DEBUG, "flushing sub-demuxer\n");
> +    avio_flush(&c->mpeg_pb.pub);
> +    ff_read_frame_flush(c->mpeg_ctx);
> +    c->play_seg_started = 0;
> +}
> +
> +static int dvdvideo_subdemux_read_data(void *opaque, uint8_t *buf, int buf_size)
> +{
> +    AVFormatContext *s = opaque;
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret = 0;
> +    int nav_event;
> +
> +    if (c->play_end)
> +        return AVERROR_EOF;
> +
> +    ret = dvdvideo_play_next_ps_block(opaque, &c->play_state, buf, buf_size,
> +                                      &nav_event, dvdvideo_subdemux_flush);
> +
> +    if (ret == AVERROR_EOF) {
> +        c->mpeg_pb.pub.eof_reached = 1;
> +        c->play_end = 1;
> +
> +        return AVERROR_EOF;
> +    }
> +
> +    if (ret >= 0 && nav_event == DVDNAV_NAV_PACKET)
> +        return FFERROR_REDO;
> +
> +    return ret;
> +}
> +
> +static void dvdvideo_subdemux_close(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    av_freep(&c->mpeg_pb.pub.buffer);
> +    av_freep(&c->mpeg_pb);
> +    avformat_close_input(&c->mpeg_ctx);
> +}
> +
> +static int dvdvideo_subdemux_open(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret = 0;
> +
> +    if (!(c->mpeg_fmt = av_find_input_format("mpeg")))
> +        return AVERROR_DEMUXER_NOT_FOUND;
> +
> +    if (!(c->mpeg_ctx = avformat_alloc_context()))
> +        return AVERROR(ENOMEM);
> +
> +    if (!(c->mpeg_buf = av_mallocz(DVDVIDEO_BLOCK_SIZE))) {
> +        avformat_free_context(c->mpeg_ctx);
> +
> +        return AVERROR(ENOMEM);
> +    }
> +
> +    ffio_init_context(&c->mpeg_pb, c->mpeg_buf, DVDVIDEO_BLOCK_SIZE, 0, s,
> +                      dvdvideo_subdemux_read_data, NULL, NULL);
> +    c->mpeg_pb.pub.seekable = 0;
> +
> +    if ((ret = ff_copy_whiteblacklists(c->mpeg_ctx, s)) < 0) {
> +        avformat_free_context(c->mpeg_ctx);
> +
> +        return ret;
> +    }
> +
> +    c->mpeg_ctx->flags = AVFMT_FLAG_CUSTOM_IO | AVFMT_FLAG_GENPTS;
> +    c->mpeg_ctx->ctx_flags |= AVFMTCTX_UNSEEKABLE;
> +    c->mpeg_ctx->probesize = 0;
> +    c->mpeg_ctx->max_analyze_duration = 0;
> +    c->mpeg_ctx->interrupt_callback = s->interrupt_callback;
> +    c->mpeg_ctx->pb = &c->mpeg_pb.pub;
> +    c->mpeg_ctx->io_open = NULL;
> +
> +    if ((ret = avformat_open_input(&c->mpeg_ctx, "", c->mpeg_fmt, NULL)) < 0) {
> +        avformat_free_context(c->mpeg_ctx);
> +
> +        return ret;

you can drop this

> +    }
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_read_header(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret = 0;
> +
> +    if (c->opt_title == 0) {
> +        av_log(s, AV_LOG_INFO, "Defaulting to title #1. "
> +                               "This is not always the main feature, validation suggested.\n");
> +
> +        c->opt_title = 1;
> +    }
> +
> +    if (c->opt_pgc) {
> +        if (c->opt_pg == 0)
> +            av_log(s, AV_LOG_ERROR, "Invalid coordinates. If -pgc is set, -pg must be set too.\n");
> +        else if (c->opt_chapter_start > 1 || c->opt_chapter_end > 0 || c->opt_preindex)
> +            av_log(s, AV_LOG_ERROR, "-pgc is not compatible with the -preindex or "
> +                                    "-chapter_start/-chapter_end options\n");
> +
> +        return AVERROR(EINVAL);
> +    }
> +
> +    if ((ret = dvdvideo_ifo_open(s)) < 0)
> +        return ret;
> +
> +    if (c->opt_preindex && (ret = dvdvideo_pgc_preindex(s)) < 0)
> +        return ret;
> +
> +    if ((ret = dvdvideo_play_open(s, &c->play_state)) < 0
> +            || (ret = dvdvideo_subdemux_open(s)) < 0
> +            || (ret = dvdvideo_video_stream_setup(s)) < 0
> +            || (ret = dvdvideo_audio_stream_add_all(s)) < 0
> +            || (ret = dvdvideo_subp_stream_add_all(s)) < 0)
> +        return ret;
> +
> +    if (!c->opt_preindex)
> +        return dvdvideo_pgc_chapters_setup(s);
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_read_packet(AVFormatContext *s, AVPacket *pkt)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret;
> +    enum AVMediaType st_type;
> +    int64_t cur_delta = 0;
> +
> +    if (c->play_end)
> +        return AVERROR_EOF;
> +
> +    ret = av_read_frame(c->mpeg_ctx, pkt);
> +
> +    if (ret < 0)
> +        return ret;
> +
> +    if (!c->play_seg_started)
> +        c->play_seg_started = 1;
> +
> +    if (pkt->stream_index >= s->nb_streams) {

> +        av_log(s, AV_LOG_DEBUG, "discarding frame with unknown stream\n");

print the unrecongnized stream index

> +        goto skip_redo;
> +    }
> +
> +    st_type = c->mpeg_ctx->streams[pkt->stream_index]->codecpar->codec_type;
> +
> +    if (!c->play_started) {
> +        if (st_type != AVMEDIA_TYPE_VIDEO || pkt->pts == AV_NOPTS_VALUE
> +                                          || pkt->dts == AV_NOPTS_VALUE
> +                                          || !(pkt->flags & AV_PKT_FLAG_KEY)) {

> +            av_log(s, AV_LOG_DEBUG, "discarding non-video-keyframe at start\n");

of packet with unset PTS/DTS at start

> +            goto skip_redo;
> +        }
> +
> +        c->first_pts = pkt->pts;
> +        c->play_started = 1;
> +
> +        pkt->pts = 0;
> +        pkt->dts = c->play_state.ts_offset - pkt->pts;
> +    } else {
> +        cur_delta = c->play_state.ts_offset - c->first_pts;
> +
> +        if (c->play_state.nb_vobus_played == 1 && (pkt->pts == AV_NOPTS_VALUE
> +                                               ||  pkt->dts == AV_NOPTS_VALUE
> +                                               || (pkt->pts + cur_delta) < 0)) {
> +            av_log(s, AV_LOG_DEBUG, "discarding frame with negative or unset timestamp "
> +                                    "(this is OK at the start of the first playback VOBU)\n");
> +            goto skip_redo;
> +        }
> +
> +        if (pkt->pts != AV_NOPTS_VALUE)
> +            pkt->pts += cur_delta;
> +        if (pkt->dts != AV_NOPTS_VALUE)
> +            pkt->dts += cur_delta;
> +    }
> +
> +    av_log(s, AV_LOG_TRACE, "st=%d pts=%ld dts=%ld ts_offset=%ld first_pts=%ld\n",
> +                            pkt->stream_index, pkt->pts, pkt->dts,
> +                            c->play_state.ts_offset, c->first_pts);
> +    if (pkt->pts < 0)
> +        av_log(s, AV_LOG_WARNING, "Invalid frame PTS @ st=%d pts=%ld dts=%ld\n",
> +                                  pkt->stream_index, pkt->pts, pkt->dts);
> +
> +    return c->play_end ? AVERROR_EOF : 0;
> +
> +skip_redo:
> +    av_packet_unref(pkt);
> +    return FFERROR_REDO;
> +}
> +
> +static int dvdvideo_close(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    dvdvideo_subdemux_close(s);
> +    dvdvideo_play_close(s, &c->play_state);
> +    dvdvideo_ifo_close(s);
> +
> +    return 0;
> +}
> +
> +#define OFFSET(x) offsetof(DVDVideoDemuxContext, x)
> +static const AVOption dvdvideo_options[] = {
> +    {"angle",           "playback angle number",                                    OFFSET(opt_angle),          AV_OPT_TYPE_INT,    { .i64=1 },     1,          9,         AV_OPT_FLAG_DECODING_PARAM },
> +    {"chapter_end",     "exit chapter (PTT) number (0=end)",                        OFFSET(opt_chapter_end),    AV_OPT_TYPE_INT,    { .i64=0 },     0,          99,        AV_OPT_FLAG_DECODING_PARAM },
> +    {"chapter_start",   "entry chapter (PTT) number",                               OFFSET(opt_chapter_start),  AV_OPT_TYPE_INT,    { .i64=1 },     1,          99,        AV_OPT_FLAG_DECODING_PARAM },
> +    {"pg",              "entry PG number (0=auto)",                                 OFFSET(opt_pg),             AV_OPT_TYPE_INT,    { .i64=0 },     0,          255,       AV_OPT_FLAG_DECODING_PARAM },
> +    {"pgc",             "entry PGC number (0=auto)",                                OFFSET(opt_pgc),            AV_OPT_TYPE_INT,    { .i64=0 },     0,          999,       AV_OPT_FLAG_DECODING_PARAM },
> +    {"preindex",        "enable for accurate chapter markers, slow (2-pass read)",  OFFSET(opt_preindex),       AV_OPT_TYPE_BOOL,   { .i64=0 },     0,          1,         AV_OPT_FLAG_DECODING_PARAM },
> +    {"region",          "playback region number (0=free)",                          OFFSET(opt_region),         AV_OPT_TYPE_INT,    { .i64=0 },     0,          8,         AV_OPT_FLAG_DECODING_PARAM },
> +    {"title",           "title number (0=auto)",                                    OFFSET(opt_title),          AV_OPT_TYPE_INT,    { .i64=0 },     0,          99,        AV_OPT_FLAG_DECODING_PARAM },
> +    {"trim",            "trim padding cells from start",                            OFFSET(opt_trim),           AV_OPT_TYPE_BOOL,   { .i64=1 },     0,          1,         AV_OPT_FLAG_DECODING_PARAM },
> +    {NULL}
> +};
> +
> +static const AVClass dvdvideo_class = {
> +    .class_name = "DVD-Video demuxer",
> +    .item_name  = av_default_item_name,
> +    .option     = dvdvideo_options,
> +    .version    = LIBAVUTIL_VERSION_INT
> +};
> +
> +const AVInputFormat ff_dvdvideo_demuxer = {
> +    .name           = "dvdvideo",
> +    .long_name      = NULL_IF_CONFIG_SMALL("DVD-Video"),
> +    .priv_class     = &dvdvideo_class,
> +    .priv_data_size = sizeof(DVDVideoDemuxContext),
> +    .flags          = AVFMT_NOFILE | AVFMT_SHOW_IDS | AVFMT_TS_DISCONT | AVFMT_NO_BYTE_SEEK | AVFMT_NOGENSEARCH | AVFMT_NOBINSEARCH,
> +    .flags_internal = FF_FMT_INIT_CLEANUP,
> +    .read_close     = dvdvideo_close,
> +    .read_header    = dvdvideo_read_header,
> +    .read_packet    = dvdvideo_read_packet
> +};

LGTM otherwise, thanks.

Thank you for your time and detailed review. I will clean all this up and
send v9

On Tue, Feb 6, 2024 at 6:53 PM Stefano Sabatini <stefasab@gmail.com> wrote:

> On date Sunday 2024-02-04 23:48:25 -0600, Marth64 wrote:
> > Sorry for the quick follow-up to v6, I wanted to get this update out now
> hopefully
> > before v6 is actually reviewed. v7 fixes a few documentation typos,
> options descriptions,
> > and log messages: nothing major. I also flattened this out to be a
> 2-patch set
> > with subtitle palette support.
> >
> > This is the result of >1yr of research and I am now very satisfied with
> it's result.
> > I will not make any more changes at this point unless it is outcome from
> a review.
> > If the community decides to merge it, I am happy to continue to improve
> it with support for
> > seeking, probing, and tests.
> >
> > Thank you so much,
> >
> >
> > Signed-off-by: Marth64 <marth64@proxyid.net>
> > ---
> >  Changelog                 |    2 +
> >  configure                 |    8 +
> >  doc/demuxers.texi         |  129 ++++
> >  libavformat/Makefile      |    1 +
> >  libavformat/allformats.c  |    1 +
> >  libavformat/dvdvideodec.c | 1410 +++++++++++++++++++++++++++++++++++++
> >  6 files changed, 1551 insertions(+)
> >  create mode 100644 libavformat/dvdvideodec.c
> >
> > diff --git a/Changelog b/Changelog
> > index c5fb21d198..88653bc6d3 100644
> > --- a/Changelog
> > +++ b/Changelog
> > @@ -24,6 +24,8 @@ version <next>:
> >  - ffmpeg CLI options may now be used as -/opt <path>, which is
> equivalent
> >    to -opt <contents of file <path>>
> >  - showinfo bitstream filter
> > +- DVD-Video demuxer, powered by libdvdnav and libdvdread
> > +
> >
> >  version 6.1:
> >  - libaribcaption decoder
> > diff --git a/configure b/configure
> > index 68f675a4bc..70c33ec96d 100755
> > --- a/configure
> > +++ b/configure
> > @@ -227,6 +227,8 @@ External library support:
> >    --enable-libdavs2        enable AVS2 decoding via libdavs2 [no]
> >    --enable-libdc1394       enable IIDC-1394 grabbing using libdc1394
> >                             and libraw1394 [no]
> > +  --enable-libdvdnav       enable libdvdnav, needed for DVD demuxing
> [no]
> > +  --enable-libdvdread      enable libdvdread, needed for DVD demuxing
> [no]
> >    --enable-libfdk-aac      enable AAC de/encoding via libfdk-aac [no]
> >    --enable-libflite        enable flite (voice synthesis) support via
> libflite [no]
> >    --enable-libfontconfig   enable libfontconfig, useful for drawtext
> filter [no]
> > @@ -1806,6 +1808,8 @@ EXTERNAL_LIBRARY_GPL_LIST="
> >      frei0r
> >      libcdio
> >      libdavs2
> > +    libdvdnav
> > +    libdvdread
> >      librubberband
> >      libvidstab
> >      libx264
> > @@ -3520,6 +3524,8 @@ dts_demuxer_select="dca_parser"
> >  dtshd_demuxer_select="dca_parser"
> >  dv_demuxer_select="dvprofile"
> >  dv_muxer_select="dvprofile"
> > +dvdvideo_demuxer_select="mpegps_demuxer"
> > +dvdvideo_demuxer_deps="libdvdnav libdvdread"
> >  dxa_demuxer_select="riffdec"
> >  eac3_demuxer_select="ac3_parser"
> >  evc_demuxer_select="evc_frame_merge_bsf evc_parser"
> > @@ -6761,6 +6767,8 @@ enabled libdav1d          && require_pkg_config
> libdav1d "dav1d >= 0.5.0" "dav1d
> >  enabled libdavs2          && require_pkg_config libdavs2 "davs2 >=
> 1.6.0" davs2.h davs2_decoder_open
> >  enabled libdc1394         && require_pkg_config libdc1394 libdc1394-2
> dc1394/dc1394.h dc1394_new
> >  enabled libdrm            && check_pkg_config libdrm libdrm xf86drm.h
> drmGetVersion
> > +enabled libdvdnav         && require_pkg_config libdvdnav "dvdnav >=
> 6.1.1" dvdnav/dvdnav.h dvdnav_open2
> > +enabled libdvdread        && require_pkg_config libdvdread "dvdread >=
> 6.1.2" dvdread/dvd_reader.h DVDOpen2 -ldvdread
> >  enabled libfdk_aac        && { check_pkg_config libfdk_aac fdk-aac
> "fdk-aac/aacenc_lib.h" aacEncOpen ||
> >                                 { require libfdk_aac
> fdk-aac/aacenc_lib.h aacEncOpen -lfdk-aac &&
> >                                   warn "using libfdk without
> pkg-config"; } }
> > diff --git a/doc/demuxers.texi b/doc/demuxers.texi
> > index e4c5b560a6..ad0906f6ec 100644
> > --- a/doc/demuxers.texi
> > +++ b/doc/demuxers.texi
> > @@ -285,6 +285,135 @@ This demuxer accepts the following option:
> >
> >  @end table
> >
> > +@section dvdvideo
> > +
> > +DVD-Video demuxer, powered by libdvdnav and libdvdread.
> > +
> > +Can directly ingest DVD titles, specifically sequential PGCs,
> > +into a conversion pipeline. Menus and seeking are not supported at this
> time.
> > +
> > +Block devices (DVD drives), ISO files, and directory structures are
> accepted.
> > +Activate with @code{-f dvdvideo} in front of one of these inputs.
> > +
> > +Underlying playback is fully handled by libdvdnav, and structure
> parsing by libdvdread.
>
> > +ffmpeg must be built with GPL library support available as well as the
> switches
> > +@code{--enable-libdvdnav} and @code{--enable-libdvdread}.
>
> FFmpeg must be built with GPL library support available as well as the
> configure switches @code{--enable-libdvdnav} and
> @code{--enable-libdvdread}.
>
> > +
> > +You will need to provide either the desired "title number" or exact
> PGC/PG coordinates.
>
> > +Many open-source DVD players and tools can aid in providing this
> information.
>
> unrelated, but it might be useful to have a -list-titles option to
> show this information
>
> > +If not specified, the demuxer will default to title 1 which works for
> many discs.
> > +However, due to the flexibility of DVD-Video, it is recommended to
> check manually.
> > +There are many discs that are authored strangely or with invalid
> headers.
> > +
> > +If the input is a real DVD drive, please note that there are some
> drives which may
> > +silently fail on reading bad sectors from the disc, returning random
> bits instead
> > +which is effectively corrupt data. This is especially prominent on
> aging or rotting discs.
> > +A second pass and integrity checks would be needed to detect the
> corruption.
>
> > +This is not an ffmpeg issue.
>
> nit: FFmpeg (ffmpeg is usually a reference to the CLI command, while
> FFmpeg refers to the projects and set of all libraries/tools)
>
> > +
> > +@subsection Background
> > +
> > +DVD-Video is not a directly accessible, linear container format in the
> > +traditional sense. Instead, it allows for complex and programmatic
> playback of
> > +carefully muxed MPEG-PS streams that are stored in headerless VOB files.
> > +To the end-user, these streams are known simply as "titles", but the
> actual
> > +logical playback sequence is defined by one or more "PGCs", or Program
> Group Chains,
> > +within the title. The PGC is in turn comprised of multiple "PGs", or
> Programs",
> > +which are the actual video segments which, for a typical movie, are
> sequentially
> > +ordered. The PGC structure, along with stream layout and metadata, are
> stored in
> > +IFO files that need to be parsed. PGCs can be thought of as playlists
> in easier terms.
> > +
> > +An actual DVD player relies on user GUI interaction via menus and an
> internal VM
> > +to drive the direction of demuxing. Generally, the user would either
> navigate (via menus)
> > +or automatically be redirected to the PGC of their choice. During this
> process and
> > +the subsequent playback, the DVD player's internal VM also maintains a
> state and
> > +executes instructions that can create jumps to different sectors during
> playback.
> > +This is why libdvdnav is involved, as a linear read of the MPEG-PS
> blobs on the
> > +disc (VOBs) is not enough to produce the right sequence in many cases.
> > +
> > +There are many other DVD structures (a long subject) that will not be
> discussed here.
> > +NAV packets, in particular, are handled by this demuxer to build
> accurate timing
> > +but not emitted as a stream. For a good high-level understanding, refer
> to:
> > +@url{
> https://code.videolan.org/videolan/libdvdnav/-/blob/master/doc/dvd_structures
> }
> > +
> > +@subsection Options
> > +
> > +This demuxer accepts the following options:
> > +
> > +@table @option
> > +
> > +@item title
>
> here and below: you might use @var{TYPE} to denote the argument/type of the
> option
>
> > +The title number to play. Must be set if @option{pgc} and @option{pg}
> are not set.
> > +Default is 0 (auto), which currently only selects the first available
> title (title 1)
> > +and notifies the user about the implications.
> > +
> > +@item chapter_start
> > +The chapter, or PTT (part-of-title), number to start at. Default is 1.
> > +
> > +@item chapter_end
> > +The chapter, or PTT (part-of-title), number to end at. Default is 0,
> > +which is a special value to signal end at the last possible chapter.
> > +
> > +@item angle
> > +The video angle number, referring to what is essentially an additional
> > +video stream that is composed from alternate frames interleaved in the
> VOBs.
> > +Default is 1.
> > +
> > +@item region
> > +The region code to use for playback. Some discs may use this to default
> playback
> > +at a particular angle in different regions. This option will not affect
> the region code
> > +of a real DVD drive, if used as an input. Default is 0, "world".
> > +
> > +@item pgc
> > +The entry PGC to start playback, in conjunction with @option{pg}.
> > +Alternative to setting @option{title}.
>
> > +Chapter markers not supported at this time.
>
> nit: are not supported ...
>
> > +Default is 0, automatically resolve from value of @option{title}.
> > +
> > +@item pg
> > +The entry PG to start playback, in conjunction with @option{pgc}.
> > +Alternative to setting @option{title}.
> > +Chapter markers not supported at this time.
>
> are not
>
> > +Default is 0, automatically resolve from value of @option{title}.
> > +
> > +@item preindex
> > +Enable this to have accurate chapter (PTT) markers and duration
> measurement,
> > +which requires a slow second pass read in order to index the chapter
>
> > +timestamps from NAV packets. This is non-ideal extra work for physical
> DVD drives.
>
> note: if this is non-idela for physical DVD drivers, what's the
> recommended use case?
>
> > +Not compatible with @option{pgc} and @option{pg}.
> > +Default is 0, false.
> > +
> > +@item trim
> > +Skip padding cells (i.e. cells shorter than 1 second) from the
> beginning.
> > +There exist many discs with filler segments at the beginning of the PGC,
> > +often with junk data intended for controlling a real DVD player's
> > +buffering speed and with no other material data value.
> > +Default is 1, true.
> > +
> > +@end table
> > +
> > +@subsection Examples
> > +
> > +@itemize
> > +@item
> > +Open title 3 from a given DVD structure:
> > +@example
> > +ffmpeg -f dvdvideo -title 3 -i <path to DVD> ...
> > +@end example
> > +
> > +@item
> > +Open chapters 3-6 from title 1 from a given DVD structure:
> > +@example
> > +ffmpeg -f dvdvideo -chapter_start 3 -chapter_end 6 -title 1 -i <path to
> DVD> ...
> > +@end example
> > +
> > +@item
> > +Open only chapter 5 from title 1 from a given DVD structure:
> > +@example
> > +ffmpeg -f dvdvideo -chapter_start 5 -chapter_end 5 -title 1 -i <path to
> DVD> ...
> > +@end example
> > +@end itemize
> > +
> >  @section ea
> >
> >  Electronic Arts Multimedia format demuxer.
> > diff --git a/libavformat/Makefile b/libavformat/Makefile
> > index 05b9b8a115..df69734877 100644
> > --- a/libavformat/Makefile
> > +++ b/libavformat/Makefile
> > @@ -192,6 +192,7 @@ OBJS-$(CONFIG_DTS_MUXER)                 += rawenc.o
> >  OBJS-$(CONFIG_DV_MUXER)                  += dvenc.o
> >  OBJS-$(CONFIG_DVBSUB_DEMUXER)            += dvbsub.o rawdec.o
> >  OBJS-$(CONFIG_DVBTXT_DEMUXER)            += dvbtxt.o rawdec.o
> > +OBJS-$(CONFIG_DVDVIDEO_DEMUXER)          += dvdvideodec.o
> >  OBJS-$(CONFIG_DXA_DEMUXER)               += dxa.o
> >  OBJS-$(CONFIG_EA_CDATA_DEMUXER)          += eacdata.o
> >  OBJS-$(CONFIG_EA_DEMUXER)                += electronicarts.o
> > diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> > index b04b43cab3..3e905c23f8 100644
> > --- a/libavformat/allformats.c
> > +++ b/libavformat/allformats.c
> > @@ -150,6 +150,7 @@ extern const AVInputFormat  ff_dv_demuxer;
> >  extern const FFOutputFormat ff_dv_muxer;
> >  extern const AVInputFormat  ff_dvbsub_demuxer;
> >  extern const AVInputFormat  ff_dvbtxt_demuxer;
> > +extern const AVInputFormat  ff_dvdvideo_demuxer;
> >  extern const AVInputFormat  ff_dxa_demuxer;
> >  extern const AVInputFormat  ff_ea_demuxer;
> >  extern const AVInputFormat  ff_ea_cdata_demuxer;
> > diff --git a/libavformat/dvdvideodec.c b/libavformat/dvdvideodec.c
> > new file mode 100644
> > index 0000000000..2e363a4a22
> > --- /dev/null
> > +++ b/libavformat/dvdvideodec.c
> > @@ -0,0 +1,1410 @@
> > +/*
> > + * DVD-Video demuxer, powered by libdvdnav and libdvdread
> > + *
> > + * This file is part of FFmpeg.
> > + *
> > + * FFmpeg is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU Lesser General Public
> > + * License as published by the Free Software Foundation; either
> > + * version 2.1 of the License, or (at your option) any later version.
> > + *
> > + * FFmpeg is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> > + * Lesser General Public License for more details.
> > + *
> > + * You should have received a copy of the GNU Lesser General Public
> > + * License along with FFmpeg; if not, write to the Free Software
> > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> 02110-1301 USA
> > + */
> > +
> > +/*
> > + * See doc/demuxers.texi for a high-level overview.
> > + *
> > + * The tactical approach is as follows:
> > + * 1) Open the volume with dvdread
> > + * 2) Analyze the user-requested title and PGC coordinates in the IFO
> structures
> > + * 3) Request playback at the coordinates and chosen angle with dvdnav
> > + * 5) Begin the playback (reading and demuxing) of MPEG-PS blocks
> > + * 6) End playback if navigation goes backwards, to a menu, or a
> different PGC or angle
> > + * 7) Close the dvdnav VM, and free dvdread's IFO structures
> > + */
> > +
> > +#include <dvdnav/dvdnav.h>
> > +#include <dvdread/dvd_reader.h>
> > +#include <dvdread/ifo_read.h>
> > +#include <dvdread/ifo_types.h>
> > +#include <dvdread/nav_read.h>
> > +
> > +#include "libavcodec/avcodec.h"
> > +#include "libavutil/avstring.h"
> > +#include "libavutil/avutil.h"
> > +#include "libavutil/intreadwrite.h"
> > +#include "libavutil/mem.h"
> > +#include "libavutil/opt.h"
> > +#include "libavutil/samplefmt.h"
> > +#include "libavutil/time.h"
> > +#include "libavutil/timestamp.h"
> > +
> > +#include "avformat.h"
> > +#include "avio_internal.h"
> > +#include "avlanguage.h"
> > +#include "demux.h"
> > +#include "internal.h"
> > +#include "url.h"
> > +
> > +#define DVDVIDEO_MAX_PS_SEARCH_BLOCKS                   128
> > +#define DVDVIDEO_BLOCK_SIZE                             2048
> > +#define DVDVIDEO_TIME_BASE_Q                            (AVRational) {
> 1, 90000 }
> > +#define DVDVIDEO_PTS_WRAP_BITS                          64 /* VOBUs use
> 32 (PES allows 33) */
> > +#define DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE                1024
> > +
> > +enum DVDVideoSubpictureViewport {
> > +    DVDVIDEO_SUBP_VIEWPORT_FULLSCREEN,
> > +    DVDVIDEO_SUBP_VIEWPORT_WIDESCREEN,
> > +    DVDVIDEO_SUBP_VIEWPORT_LETTERBOX,
> > +    DVDVIDEO_SUBP_VIEWPORT_PANSCAN
> > +};
> > +const char* VIEWPORT_LABELS[4] = { "Fullscreen", "Widescreen",
> "Letterbox", "Pan and Scan" };
> > +
> > +typedef struct DVDVideoVTSVideoStreamEntry {
> > +    int startcode;
> > +    enum AVCodecID codec_id;
> > +    int width;
> > +    int height;
> > +    AVRational dar;
> > +    AVRational framerate;
> > +    int has_cc;
> > +} DVDVideoVTSVideoStreamEntry;
> > +
> > +typedef struct DVDVideoPGCAudioStreamEntry {
> > +    int startcode;
> > +    enum AVCodecID codec_id;
> > +    int sample_fmt;
> > +    int sample_rate;
> > +    int bit_depth;
> > +    int nb_channels;
> > +    AVChannelLayout ch_layout;
> > +    int disposition;
> > +    char *lang_iso;
> > +} DVDVideoPGCAudioStreamEntry;
> > +
> > +typedef struct DVDVideoPGCSubtitleStreamEntry {
> > +    int startcode;
> > +    int disposition;
> > +    char *lang_iso;
> > +    enum DVDVideoSubpictureViewport viewport;
> > +} DVDVideoPGCSubtitleStreamEntry;
> > +
> > +typedef struct DVDVideoPlaybackState {
> > +    int                         celln;              /* ID of the active
> cell */
> > +    int                         entry_pgn;          /* ID of the PG we
> are starting in */
> > +    int                         in_pgc;             /* if our navigator
> is in the PGC */
> > +    int                         in_ps;              /* if our navigator
> is in the program stream */
> > +    int                         in_vts;             /* if our navigator
> is in the VTS */
> > +    int64_t                     nav_pts;            /* PTS according to
> IFO, not frame-accurate */
> > +    int                         nb_vobus_played;    /* number of VOBUs
> played back so far */
> > +    uint64_t                    pgc_duration_est;   /* estimated
> duration as reported by IFO */
> > +    uint64_t                    pgc_elapsed;        /* the elapsed time
> of the PGC, cell-relative */
> > +    int                         pgc_nb_pg_est;      /* number of PGs as
> reported by IFOs */
> > +    int                         pgcn;               /* ID of the PGC we
> are playing */
> > +    int                         pgn;                /* ID of the PG we
> are in now */
> > +    int                         ptt;                /* ID of the
> chapter we are in now */
> > +    int64_t                     ts_offset;          /* PTS
> discontinuity offset (ex. VOB change) */
> > +    uint32_t                    vobu_duration;      /* duration of the
> current VOBU */
> > +    uint32_t                    vobu_e_ptm;         /* end PTS of the
> current VOBU */
> > +    int                         vtsn;               /* ID of the active
> VTS (video title set) */
> > +    uint64_t                    *pgc_pg_times_est;  /* PG start times
> as reported by IFO */
> > +    pgc_t                       *pgc;               /* handle to the
> active PGC */
> > +    dvdnav_t                    *dvdnav;            /* handle to
> libdvdnav */
> > +} DVDVideoPlaybackState;
> > +
> > +typedef struct DVDVideoDemuxContext {
> > +    const AVClass               *class;
> > +
> > +    /* options */
> > +    int                         opt_title;          /* the
> user-provided title number (1-indexed) */
> > +    int                         opt_chapter_start;  /* the
> user-provided entry PTT (1-indexed) */
> > +    int                         opt_chapter_end;    /* the
> user-provided exit PTT (0 for last) */
> > +    int                         opt_pgc;            /* the
> user-provided PGC number (1-indexed) */
> > +    int                         opt_pg;             /* the
> user-provided PG number (1-indexed) */
> > +    int                         opt_angle;          /* the
> user-provided angle number (1-indexed) */
> > +    int                         opt_region;         /* the
> user-provided region digit */
> > +    int                         opt_preindex;       /* pre-indexing
> mode (2-pass read) */
> > +    int                         opt_trim;           /* trim padding
> cells at beginning and end */
> > +
> > +    /* subdemux */
> > +    const AVInputFormat         *mpeg_fmt;          /* inner MPEG-PS
> (VOB) demuxer */
> > +    AVFormatContext             *mpeg_ctx;          /* context for
> inner demuxer */
> > +    uint8_t                     *mpeg_buf;          /* buffer for inner
> demuxer */
> > +    FFIOContext                 mpeg_pb;            /* buffer context
> for inner demuxer */
> > +
> > +    /* volume */
> > +    dvd_reader_t                *dvdread;           /* handle to
> libdvdread */
> > +    ifo_handle_t                *vmg_ifo;           /* handle to the
> VMG (VIDEO_TS.IFO) */
> > +    ifo_handle_t                *vts_ifo;           /* handle to the
> active VTS (VTS_nn_n.IFO) */
> > +
> > +    /* playback control */
> > +    int                         play_end;           /* signal EOF to
> the parent demuxer */
> > +    DVDVideoPlaybackState       play_state;         /* the active
> playback state */
> > +    int                         play_started;       /* signal that
> playback has started */
> > +    int                         play_seg_started;   /* signal that
> segment has started */
> > +    int64_t                     first_pts;          /* the starting PTS
> offset of the PGC */
> > +    uint64_t                    duration_ptm;       /* total duration
> in DVD MPEG timebase */
> > +} DVDVideoDemuxContext;
> > +
> > +static void dvdvideo_libdvdread_log(void *opaque, dvd_logger_level_t
> level,
> > +                                    const char *msg, va_list msg_va)
> > +{
> > +    AVFormatContext *s = opaque;
> > +    int lavu_level;
> > +
> > +    char msg_buf[DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE] = {0};
> > +    vsnprintf(msg_buf, DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE, msg, msg_va);
> > +
> > +    switch (level) {
> > +        case DVD_LOGGER_LEVEL_ERROR:
> > +            lavu_level = AV_LOG_ERROR;
> > +            break;
> > +        case DVD_LOGGER_LEVEL_WARN:
> > +            lavu_level = AV_LOG_WARNING;
> > +            break;
> > +        /* dvdread's info messages are relatively very verbose, muffle
> them as debug */
> > +        case DVD_LOGGER_LEVEL_INFO:
> > +        case DVD_LOGGER_LEVEL_DEBUG:
> > +        default:
> > +            lavu_level = AV_LOG_DEBUG;
> > +    }
> > +
> > +    av_log(s, lavu_level, "libdvdread: %s\n", msg_buf);
> > +}
> > +
> > +static void dvdvideo_libdvdnav_log(void *opaque, dvdnav_logger_level_t
> level,
> > +                                   const char *msg, va_list msg_va)
> > +{
> > +    AVFormatContext *s = opaque;
> > +    int lavu_level;
> > +
> > +    char msg_buf[DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE] = {0};
> > +    vsnprintf(msg_buf, DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE, msg, msg_va);
> > +
> > +    switch (level) {
> > +        case DVDNAV_LOGGER_LEVEL_ERROR:
> > +            lavu_level = AV_LOG_ERROR;
> > +            break;
> > +        case DVDNAV_LOGGER_LEVEL_WARN:
> > +            /* some discs have invalid language codes set for their
> menus, muffle the noise */
> > +            lavu_level = av_strstart(msg, "Language", NULL) ?
> AV_LOG_DEBUG : AV_LOG_WARNING;
> > +            break;
> > +        /* dvdnav's info messages are relatively very verbose, muffle
> them as debug */
> > +        case DVDNAV_LOGGER_LEVEL_INFO:
> > +        case DVDNAV_LOGGER_LEVEL_DEBUG:
> > +        default:
> > +            lavu_level = AV_LOG_DEBUG;
> > +    }
> > +
> > +    av_log(s, lavu_level, "libdvdnav: %s\n", msg_buf);
> > +}
> > +
> > +static void dvdvideo_ifo_close(AVFormatContext *s)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    if (c->vts_ifo)
> > +        ifoClose(c->vts_ifo);
> > +
> > +    if (c->vmg_ifo)
> > +        ifoClose(c->vmg_ifo);
> > +
> > +    if (c->dvdread)
> > +        DVDClose(c->dvdread);
> > +}
> > +
> > +static int dvdvideo_ifo_open(AVFormatContext *s)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    dvd_logger_cb dvdread_log_cb;
> > +    title_info_t title_info;
> > +
> > +    dvdread_log_cb = (dvd_logger_cb) { .pf_log =
> dvdvideo_libdvdread_log };
> > +    c->dvdread = DVDOpen2(s, &dvdread_log_cb, s->url);
> > +
> > +    if (!c->dvdread) {
> > +        av_log(s, AV_LOG_ERROR, "Unable to open the DVD-Video
> structure\n");
> > +
> > +        return AVERROR_EXTERNAL;
> > +    }
> > +
> > +    if (!(c->vmg_ifo = ifoOpen(c->dvdread, 0))) {
> > +        av_log(s, AV_LOG_ERROR, "Unable to open the VMG
> (VIDEO_TS.IFO)\n");
> > +
> > +        return AVERROR_EXTERNAL;
> > +    }
> > +
> > +    if (c->opt_title > c->vmg_ifo->tt_srpt->nr_of_srpts) {
> > +        av_log(s, AV_LOG_ERROR, "Title %d not found\n", c->opt_title);
> > +
> > +        return AVERROR_STREAM_NOT_FOUND;
> > +    }
> > +
> > +    title_info = c->vmg_ifo->tt_srpt->title[c->opt_title - 1];
> > +    if (c->opt_angle > title_info.nr_of_angles) {
> > +        av_log(s, AV_LOG_ERROR, "Angle %d not found\n", c->opt_angle);
> > +
> > +        return AVERROR_STREAM_NOT_FOUND;
> > +    }
> > +
> > +    if (title_info.nr_of_ptts < 1) {
> > +        av_log(s, AV_LOG_ERROR, "Title %d has invalid headers (no
> parts)\n", c->opt_title);
> > +
> > +        return AVERROR_INVALIDDATA;
> > +    }
> > +
> > +    if (c->opt_chapter_start > title_info.nr_of_ptts
> > +            || (c->opt_chapter_end > 0 && c->opt_chapter_end >
> title_info.nr_of_ptts)) {
> > +        av_log(s, AV_LOG_ERROR, "Chapter (PTT) range [%d, %d] is
> invalid\n",
> > +                                c->opt_chapter_start,
> c->opt_chapter_end);
> > +
> > +        return AVERROR_INVALIDDATA;
> > +    }
> > +
> > +    if (!(c->vts_ifo = ifoOpen(c->dvdread, title_info.title_set_nr))) {
> > +        av_log(s, AV_LOG_ERROR, "Unable to process the VTS IFO
> structure\n");
> > +
> > +        return AVERROR_EXTERNAL;
> > +    }
> > +
> > +    if (title_info.vts_ttn < 1
> > +            || title_info.vts_ttn > 99
> > +            || title_info.vts_ttn >
> c->vts_ifo->vts_ptt_srpt->nr_of_srpts
> > +            || c->vts_ifo->vtsi_mat->nr_of_vts_audio_streams > 8
> > +            || c->vts_ifo->vtsi_mat->nr_of_vts_subp_streams > 32) {
> > +        av_log(s, AV_LOG_ERROR, "Title %d has invalid headers in
> VTS\n", c->opt_title);
> > +
> > +        return AVERROR_INVALIDDATA;
> > +    }
> > +
> > +    return 0;
> > +}
> > +
> > +static void dvdvideo_play_close(AVFormatContext *s,
> DVDVideoPlaybackState *state)
> > +{
> > +    if (!state->dvdnav)
> > +        return;
> > +
> > +    /* not allocated by av_malloc() */
> > +    if (state->pgc_pg_times_est)
> > +        free(state->pgc_pg_times_est);
> > +
>
> > +    if (dvdnav_close(state->dvdnav) < 0)
> > +        av_log(s, AV_LOG_ERROR, "Unable to cleanly close dvdnav\n");
>
> nit: in case this has consquence, you might print the error code in
> the log
>
> > +}
> > +
> > +static int dvdvideo_play_open(AVFormatContext *s, DVDVideoPlaybackState
> *state)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    int ret = 0;
> > +    dvdnav_logger_cb dvdnav_log_cb;
> > +    dvdnav_status_t dvdnav_open_status;
> > +    int cur_title, cur_pgcn, cur_pgn;
> > +    pgc_t *pgc;
> > +
> > +    int32_t disc_region_mask;
> > +    int32_t player_region_mask;
> > +
> > +    dvdnav_log_cb = (dvdnav_logger_cb) { .pf_log =
> dvdvideo_libdvdnav_log };
> > +    dvdnav_open_status = dvdnav_open2(&state->dvdnav, s,
> &dvdnav_log_cb, s->url);
> > +
>
> > +    if (!state->dvdnav
> > +            || dvdnav_open_status != DVDNAV_STATUS_OK
> > +            || dvdnav_set_readahead_flag(state->dvdnav, 0) !=
> DVDNAV_STATUS_OK
> > +            || dvdnav_set_PGC_positioning_flag(state->dvdnav, 1) !=
> DVDNAV_STATUS_OK
> > +            || dvdnav_get_region_mask(state->dvdnav, &disc_region_mask)
> != DVDNAV_STATUS_OK) {
>
> nit+: here and below, weird style
>
> usually || is put at the EOL and conditions are aligned, as in
>
> if (foo ||
>     bar ||
>     baz) {
>     ...
> }
>
> > +        av_log(s, AV_LOG_ERROR, "Unable to open the DVD for
> playback\n");
> > +
> > +        return AVERROR_EXTERNAL;
> > +    }
> > +
> > +    player_region_mask = c->opt_region > 0 ? (1 << (c->opt_region - 1))
> : disc_region_mask;
> > +    if (dvdnav_set_region_mask(state->dvdnav, player_region_mask) !=
> DVDNAV_STATUS_OK) {
> > +        av_log(s, AV_LOG_ERROR, "Unable to set the playback region code
> %d\n", c->opt_region);
> > +
> > +        return AVERROR_EXTERNAL;
> > +    }
> > +
> > +    if (c->opt_pgc > 0 && c->opt_pg > 0) {
> > +        if (dvdnav_program_play(state->dvdnav, c->opt_title,
> > +                                c->opt_pgc, c->opt_pg) !=
> DVDNAV_STATUS_OK) {
> > +            av_log(s, AV_LOG_ERROR, "Unable to start playback at title
> %d, PGC %d, PG %d\n",
> > +                                    c->opt_title, c->opt_pgc,
> c->opt_pg);
> > +
> > +            return AVERROR_EXTERNAL;
> > +        }
> > +
> > +        state->pgcn = c->opt_pgc;
> > +        state->entry_pgn = c->opt_pg;
> > +    } else {
> > +        if (dvdnav_part_play(state->dvdnav, c->opt_title,
> c->opt_chapter_start) != DVDNAV_STATUS_OK
> > +                || dvdnav_current_title_program(state->dvdnav,
> &cur_title,
> > +                                                &cur_pgcn, &cur_pgn) !=
> DVDNAV_STATUS_OK) {
> > +            av_log(s, AV_LOG_ERROR, "Unable to start playback at title
> %d, chapter (PTT) %d\n",
> > +                                    c->opt_title, c->opt_chapter_start);
> > +
> > +            return AVERROR_EXTERNAL;
> > +        }
> > +
> > +        state->pgcn = cur_pgcn;
> > +        state->entry_pgn = cur_pgn;
> > +    }
> > +
> > +    pgc = c->vts_ifo->vts_pgcit->pgci_srp[state->pgcn - 1].pgc;
> > +
> > +    if (pgc->pg_playback_mode != 0) {
> > +        av_log(s, AV_LOG_ERROR, "Non-sequential PGCs, such as shuffles,
> are not supported\n");
> > +
> > +        return AVERROR_PATCHWELCOME;
> > +    }
> > +
> > +    if (dvdnav_angle_change(state->dvdnav, c->opt_angle) !=
> DVDNAV_STATUS_OK) {
>
> > +        av_log(s, AV_LOG_ERROR, "Unable to start playback at the given
> angle\n");
>
> nit: you might mention the failing angle here
>
> > +
> > +        return AVERROR_EXTERNAL;
> > +    }
> > +
> > +    /* dvdnav_describe_title_chapters() performs several safety checks
> on the title structure */
> > +    /* take advantage of this side effect to ensure a safe navigation
> path */
> > +    state->pgc_nb_pg_est =
> dvdnav_describe_title_chapters(state->dvdnav, c->opt_title,
> > +
> &state->pgc_pg_times_est,
> > +
> &state->pgc_duration_est);
> > +    if (!state->pgc_nb_pg_est) {
> > +        av_log(s, AV_LOG_ERROR, "Unable to validate title structure\n");
> > +
> > +        return AVERROR_EXTERNAL;
> > +    }
> > +
> > +    state->nav_pts = dvdnav_get_current_time(state->dvdnav);
> > +    state->vtsn = c->vmg_ifo->tt_srpt->title[c->opt_title -
> 1].title_set_nr;
> > +
> > +    state->pgc = pgc;
> > +
> > +    return ret;
> > +}
> > +
> > +static int dvdvideo_play_is_cell_promising(AVFormatContext *s,
> DVDVideoPlaybackState *state,
> > +                                           int celln)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +    dvd_time_t cell_duration;
> > +
> > +    if (!c->opt_trim)
> > +        return 1;
> > +
> > +    cell_duration = state->pgc->cell_playback[celln - 1].playback_time;
> > +
> > +    return cell_duration.second >= 1 || cell_duration.minute >= 1 ||
> cell_duration.hour >= 1;
> > +}
> > +
> > +static int dvdvideo_play_next_ps_block(AVFormatContext *s,
> DVDVideoPlaybackState *state,
> > +                                       uint8_t *buf, int buf_size,
> > +                                       int *p_nav_event,
> > +                                       void (*flush_cb)(AVFormatContext
> *s))
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    uint8_t nav_buf[DVDVIDEO_BLOCK_SIZE] = {0};
> > +    int nav_event;
> > +    int nav_len;
> > +
> > +    dvdnav_vts_change_event_t *e_vts;
> > +    dvdnav_cell_change_event_t *e_cell;
> > +    int cur_title, cur_pgcn, cur_pgn, cur_angle, cur_title_unused,
> cur_ptt, cur_nb_angles;
> > +    int is_cell_promising = 0;
> > +    pci_t *e_pci;
> > +    dsi_t *e_dsi;
> > +
>
> > +    if (buf_size != DVDVIDEO_BLOCK_SIZE) {
> > +        av_log(s, AV_LOG_ERROR, "Invalid buffer size\n");
>
> you might mention the failing size (Invalid buffer size %d, the DVD block
> size %d was expected)
>
> > +
> > +        return AVERROR(ENOMEM);
>
> Not sure this is the correct error (it's not an allocation error)
> maybe more invaliddata or EINVAL.
>
> > +    }
> > +
> > +    for (int i = 0; i < DVDVIDEO_MAX_PS_SEARCH_BLOCKS; i++) {
> > +        if (ff_check_interrupt(&s->interrupt_callback))
> > +            return AVERROR_EXIT;
> > +
> > +        if (dvdnav_get_next_block(state->dvdnav, nav_buf, &nav_event,
> &nav_len) != DVDNAV_STATUS_OK) {
> > +            av_log(s, AV_LOG_ERROR, "Unable to read next block of
> PGC\n");
> > +
> > +            return AVERROR_INVALIDDATA;
> > +        }
> > +
> > +        /* some discs follow NOPs with a premature stop event */
> > +        if (nav_event == DVDNAV_STOP)
> > +            return AVERROR_EOF;
> > +
> > +        if (nav_len > DVDVIDEO_BLOCK_SIZE) {
> > +            av_log(s, AV_LOG_ERROR, "Invalid block size\n");
> > +
> > +            return AVERROR_INVALIDDATA;
> > +        }
> > +
> > +        if (dvdnav_current_title_info(state->dvdnav, &cur_title,
> > +                                      &cur_ptt) != DVDNAV_STATUS_OK) {
> > +            av_log(s, AV_LOG_ERROR, "Unable to validate title
> coordinates\n");
> > +
> > +            return AVERROR_INVALIDDATA;
> > +        }
> > +
> > +        /* we somehow navigated to a menu */
> > +        if (cur_title == 0 || !dvdnav_is_domain_vts(state->dvdnav))
> > +            return AVERROR_EOF;
> > +
> > +        if (dvdnav_current_title_program(state->dvdnav,
> &cur_title_unused,
> > +                                         &cur_pgcn, &cur_pgn) !=
> DVDNAV_STATUS_OK) {
> > +            av_log(s, AV_LOG_ERROR, "Unable to validate PGC
> coordinates\n");
> > +
> > +            return AVERROR_INVALIDDATA;
> > +        }
> > +
> > +        /* we somehow left the PGC */
> > +        if (state->in_pgc && cur_pgcn != state->pgcn)
> > +            return AVERROR_EOF;
> > +
> > +        if (dvdnav_get_angle_info(state->dvdnav, &cur_angle,
> &cur_nb_angles) != DVDNAV_STATUS_OK) {
> > +            av_log(s, AV_LOG_ERROR, "Unable to validate angle
> coordinates\n");
> > +
> > +            return AVERROR_INVALIDDATA;
> > +        }
> > +
> > +        av_log(s, nav_event == DVDNAV_BLOCK_OK ? AV_LOG_TRACE :
> AV_LOG_DEBUG,
>
> > +                                "new block: i=%d nav_event=%d
> nav_len=%d cur_title=%d "
> > +                                "cur_ptt=%d cur_angle=%d cur_celln=%d
> cur_pgcn=%d cur_pgn=%d "
> > +                                "play_in_vts=%d play_in_pgc=%d
> play_in_ps=%d\n",
> > +                                i, nav_event, nav_len, cur_title,
> > +                                cur_ptt, cur_angle, state->celln,
> cur_pgcn, cur_pgn,
> > +                                state->in_vts, state->in_pgc,
> state->in_ps);
>
> nit: weird indent
>
> > +
> > +        switch (nav_event) {
> > +            case DVDNAV_VTS_CHANGE:
> > +                if (state->in_vts)
> > +                    return AVERROR_EOF;
> > +
> > +                e_vts = (dvdnav_vts_change_event_t *) nav_buf;
> > +
> > +                if (e_vts->new_vtsN == state->vtsn && e_vts->new_domain
> == DVD_DOMAIN_VTSTitle)
> > +                    state->in_vts = 1;
> > +
> > +                continue;
> > +            case DVDNAV_CELL_CHANGE:
> > +                if (!state->in_vts)
> > +                    continue;
> > +
> > +                e_cell = (dvdnav_cell_change_event_t *) nav_buf;
> > +                is_cell_promising = dvdvideo_play_is_cell_promising(s,
> state, e_cell->cellN);
> > +
> > +                av_log(s, AV_LOG_DEBUG, "new cell: prev=%d new=%d
> promising=%d\n",
> > +                                        state->celln, e_cell->cellN,
> is_cell_promising);
> > +
> > +                if (!state->in_ps && !state->in_pgc) {
>
> > +                    if (cur_title == c->opt_title && cur_ptt ==
> c->opt_chapter_start
> > +                            && cur_pgcn == state->pgcn && cur_pgn ==
> state->entry_pgn
> > +                            && is_cell_promising) {
>
> nit: weird align
>
> > +                        state->in_pgc = 1;
> > +                    }
> > +
> > +                    if (c->opt_trim && !is_cell_promising)
> > +                        av_log(s, AV_LOG_INFO, "Skipping padding cell
> #%d\n", e_cell->cellN);
> > +                } else if (state->celln >= e_cell->cellN || state->pgn
> > cur_pgn) {
> > +                    return AVERROR_EOF;
> > +                }
> > +
> > +                state->celln = e_cell->cellN;
> > +                state->ptt = cur_ptt;
> > +                state->pgn = cur_pgn;
> > +
> > +                continue;
> > +            case DVDNAV_NAV_PACKET:
> > +                if (!state->in_pgc)
> > +                    continue;
> > +
> > +                if ((state->ptt > 0 && state->ptt > cur_ptt)
> > +                        || (c->opt_chapter_end > 0 && cur_ptt >
> c->opt_chapter_end)) {
> > +                    return AVERROR_EOF;
> > +                }
> > +
> > +                e_pci = dvdnav_get_current_nav_pci(state->dvdnav);
> > +                e_dsi = dvdnav_get_current_nav_dsi(state->dvdnav);
> > +
> > +                if (e_pci == NULL || e_dsi == NULL
> > +                                  || e_pci->pci_gi.vobu_s_ptm >
> e_pci->pci_gi.vobu_e_ptm) {
> > +                    av_log(s, AV_LOG_ERROR, "Invalid NAV packet\n");
> > +
> > +                    return AVERROR_INVALIDDATA;
> > +                }
> > +
> > +                state->vobu_duration = e_pci->pci_gi.vobu_e_ptm -
> e_pci->pci_gi.vobu_s_ptm;
> > +                state->pgc_elapsed += state->vobu_duration;
> > +                state->nav_pts = dvdnav_get_current_time(state->dvdnav);
> > +                state->ptt = cur_ptt;
> > +                state->pgn = cur_pgn;
> > +                state->nb_vobus_played++;
> > +
> > +                av_log(s, AV_LOG_DEBUG, "NAV pack: s_ptm=%d e_ptm=%d "
> > +                                        "scr=%d lbn=%d vobu_duration=%d
> nav_pts=%ld\n",
> > +                            e_pci->pci_gi.vobu_s_ptm,
> e_pci->pci_gi.vobu_e_ptm,
> > +                            e_dsi->dsi_gi.nv_pck_scr,
> > +                            e_pci->pci_gi.nv_pck_lbn,
> state->vobu_duration, state->nav_pts);
> > +
> > +                if (!state->in_ps) {
> > +                    av_log(s, AV_LOG_DEBUG, "navigation: locked to
> program stream\n");
> > +
> > +                    state->in_ps = 1;
> > +                } else {
> > +                    if (state->vobu_e_ptm != e_pci->pci_gi.vobu_s_ptm) {
> > +                        if (flush_cb)
> > +                            flush_cb(s);
> > +
> > +                        state->ts_offset += state->vobu_e_ptm -
> e_pci->pci_gi.vobu_s_ptm;
> > +                    }
> > +                }
> > +
> > +                state->vobu_e_ptm = e_pci->pci_gi.vobu_e_ptm;
> > +
> > +                (*p_nav_event) = nav_event;
> > +
> > +                return nav_len;
> > +            case DVDNAV_BLOCK_OK:
> > +                if (!state->in_ps) {
> > +                    if (state->in_pgc)
> > +                        i = 0; /* necessary in case we are skipping
> junk cells at the beginning */
> > +                    continue;
> > +                }
> > +
> > +                if (nav_len != DVDVIDEO_BLOCK_SIZE) {
> > +                    av_log(s, AV_LOG_ERROR, "Invalid block size\n");
> > +
> > +                    return AVERROR_INVALIDDATA;
> > +                }
> > +
> > +                if (cur_angle != c->opt_angle) {
> > +                    av_log(s, AV_LOG_ERROR, "Unexpected angle
> change\n");
> > +
> > +                    return AVERROR_INPUT_CHANGED;
> > +                }
> > +
> > +                memcpy(buf, &nav_buf, nav_len);
> > +
> > +                /* in case NAV packet is missed */
> > +                state->ptt = cur_ptt;
> > +                state->pgn = cur_pgn;
> > +
> > +                (*p_nav_event) = nav_event;
> > +
> > +                return nav_len;
> > +            case DVDNAV_STILL_FRAME:
> > +            case DVDNAV_WAIT:
> > +            case DVDNAV_HOP_CHANNEL:
> > +            case DVDNAV_HIGHLIGHT:
> > +                if (state->in_ps)
> > +                    return AVERROR_EOF;
> > +
> > +                if (nav_event == DVDNAV_STILL_FRAME)
> > +                    dvdnav_still_skip(state->dvdnav);
> > +                if (nav_event == DVDNAV_WAIT)
> > +                    dvdnav_wait_skip(state->dvdnav);
> > +
> > +                continue;
> > +            case DVDNAV_STOP:
> > +                return AVERROR_EOF;
> > +            default:
> > +                continue;
> > +        }
> > +    }
> > +
> > +    av_log(s, AV_LOG_ERROR, "Unable to find next program stream
> block\n");
> > +
> > +    return AVERROR_INVALIDDATA;
> > +}
> > +
> > +static int dvdvideo_pgc_preindex(AVFormatContext *s)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    int ret = 0, interrupt = 0;
> > +    int nb_chapters = 0, last_ptt = c->opt_chapter_start;
> > +    uint64_t cur_chapter_offset = 0, cur_chapter_duration = 0;
> > +    DVDVideoPlaybackState *state;
> > +
> > +    uint8_t nav_buf[DVDVIDEO_BLOCK_SIZE];
> > +    int nav_event;
> > +
> > +    if (c->opt_chapter_start == c->opt_chapter_end)
> > +        return 0;
> > +
> > +    av_log(s, AV_LOG_INFO,
> > +           "Indexing chapter markers, this will take a long time.
> Please wait...\n");
> > +
> > +    state = av_mallocz(sizeof(DVDVideoPlaybackState));
> > +    if ((ret = dvdvideo_play_open(s, state)) < 0) {
> > +        av_freep(&state);
> > +        return ret;
> > +    }
> > +
> > +    while (!(interrupt = ff_check_interrupt(&s->interrupt_callback))) {
> > +        ret = dvdvideo_play_next_ps_block(s, state, nav_buf,
> DVDVIDEO_BLOCK_SIZE,
> > +                                          &nav_event, NULL);
> > +        if (ret < 0 && ret != AVERROR_EOF)
> > +            goto end_free;
> > +
> > +        if (nav_event != DVDNAV_NAV_PACKET && ret != AVERROR_EOF)
> > +            continue;
> > +
> > +        if (state->ptt == last_ptt) {
> > +            cur_chapter_duration += state->vobu_duration;
> > +            /* ensure we add the last chapter */
> > +            if (ret != AVERROR_EOF)
> > +                continue;
> > +        }
> > +
>
> > +        if (!avpriv_new_chapter(s, nb_chapters, DVDVIDEO_TIME_BASE_Q,
> cur_chapter_offset,
> > +                                cur_chapter_offset +
> cur_chapter_duration, NULL)) {
> > +            av_log(s, AV_LOG_ERROR, "Unable to allocate chapter\n");
>
> ret is not set in this case
>
> > +
> > +            goto end_free;
> > +        }
> > +
> > +        nb_chapters++;
> > +        cur_chapter_offset += cur_chapter_duration;
> > +        cur_chapter_duration = state->vobu_duration;
> > +        last_ptt = state->ptt;
> > +
> > +        if (ret == AVERROR_EOF)
> > +            break;
> > +    }
> > +
> > +    if (interrupt) {
> > +        ret = AVERROR_EXIT;
> > +        goto end_free;
> > +    }
> > +
> > +    if (ret < 0 && ret != AVERROR_EOF)
> > +        goto end_free;
> > +
> > +    s->duration = av_rescale_q(state->pgc_elapsed,
> DVDVIDEO_TIME_BASE_Q, AV_TIME_BASE_Q);
> > +    c->duration_ptm = state->pgc_elapsed;
> > +
> > +    av_log(s, AV_LOG_INFO, "Chapter marker indexing complete\n");
> > +    ret = 0;
> > +
> > +end_free:
> > +    dvdvideo_play_close(s, state);
> > +    av_freep(&state);
> > +
> > +    return ret;
> > +}
> > +
> > +static int dvdvideo_pgc_chapters_setup(AVFormatContext *s)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    uint64_t time_prev = 0;
> > +    int64_t total_duration = 0;
> > +
> > +    int chapter_start = c->opt_chapter_start - 1;
> > +    int chapter_end = c->opt_chapter_end > 0 ? c->opt_chapter_end :
> c->play_state.pgc_nb_pg_est - 1;
> > +
> > +    if (chapter_start == chapter_end || c->play_state.pgc_nb_pg_est ==
> 1) {
> > +        s->duration = av_rescale_q(c->play_state.pgc_duration_est,
> > +                                   DVDVIDEO_TIME_BASE_Q,
> AV_TIME_BASE_Q);
> > +        return 0;
> > +    }
> > +
> > +    for (int i = chapter_start; i < chapter_end; i++) {
> > +        uint64_t time_effective = c->play_state.pgc_pg_times_est[i] -
> c->play_state.nav_pts;
> > +
> > +        if (!avpriv_new_chapter(s, i, DVDVIDEO_TIME_BASE_Q, time_prev,
> > +                                time_effective, NULL)) {
> > +            av_log(s, AV_LOG_ERROR, "Unable to allocate chapter\n");
> > +            return AVERROR(ENOMEM);
> > +        }
> > +
> > +        time_prev = time_effective;
> > +        total_duration = time_effective;
> > +    }
> > +
> > +    if (c->opt_chapter_start == 1 && c->opt_chapter_end == 0)
> > +        s->duration = av_rescale_q(c->play_state.pgc_duration_est,
> > +                                   DVDVIDEO_TIME_BASE_Q,
> AV_TIME_BASE_Q);
> > +    else
> > +        s->duration = av_rescale_q(total_duration,
> > +                                   DVDVIDEO_TIME_BASE_Q,
> AV_TIME_BASE_Q);
> > +
> > +    return 0;
> > +}
> > +
> > +static int dvdvideo_video_stream_analyze(AVFormatContext *s,
> video_attr_t video_attr,
> > +                                         DVDVideoVTSVideoStreamEntry
> *entry)
> > +{
> > +    AVRational framerate;
> > +    int height = 0;
> > +    int width = 0;
> > +    int is_pal = video_attr.video_format == 1;
> > +
> > +    framerate = is_pal ? (AVRational) { 25, 1 } : (AVRational) { 30000,
> 1001 };
> > +    height = is_pal ? 576 : 480;
> > +
> > +    if (height > 0) {
> > +        switch (video_attr.picture_size) {
> > +            case 0: /* D1 */
> > +                width = 720;
> > +                break;
> > +            case 1: /* 4CIF */
> > +                width = 704;
> > +                break;
> > +            case 2: /* Half D1 */
> > +                width = 352;
> > +                break;
> > +            case 3: /* CIF */
> > +                width = 352;
> > +                height /= 2;
> > +                break;
> > +        }
> > +    }
> > +
> > +    if (!width || !height) {
>
> > +        av_log(s, AV_LOG_ERROR, "Invalid video dimensions\n");
>
> you might print the actual size to help debug impossible cases
>
> > +
> > +        return AVERROR_INVALIDDATA;
> > +    }
> > +
> > +    entry->startcode = 0x1E0;
> > +    entry->codec_id = !video_attr.mpeg_version ? AV_CODEC_ID_MPEG1VIDEO
> : AV_CODEC_ID_MPEG2VIDEO;
> > +    entry->width = width;
> > +    entry->height = height;
> > +    entry->dar = video_attr.display_aspect_ratio ? (AVRational) { 16, 9
> } : (AVRational) { 4, 3 };
> > +    entry->framerate = framerate;
> > +    entry->has_cc = !is_pal && (video_attr.line21_cc_1 ||
> video_attr.line21_cc_2);
> > +
> > +    return 0;
> > +}
> > +
> > +static int dvdvideo_video_stream_add(AVFormatContext *s,
> > +                                     DVDVideoVTSVideoStreamEntry *entry,
> > +                                     enum AVStreamParseType
> need_parsing)
> > +{
> > +    AVStream *st;
> > +    FFStream *sti;
> > +
> > +    st = avformat_new_stream(s, NULL);
> > +    if (!st)
> > +        return AVERROR(ENOMEM);
> > +
> > +    st->id = entry->startcode;
> > +    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
> > +    st->codecpar->codec_id = entry->codec_id;
> > +    st->codecpar->width = entry->width;
> > +    st->codecpar->height = entry->height;
> > +    st->codecpar->format = AV_PIX_FMT_YUV420P;
> > +    st->codecpar->color_range = AVCOL_RANGE_MPEG;
> > +
> > +    st->codecpar->framerate = entry->framerate;
> > +#if FF_API_R_FRAME_RATE
> > +    st->r_frame_rate = entry->framerate;
> > +#endif
> > +    st->avg_frame_rate = entry->framerate;
> > +
> > +    sti = ffstream(st);
> > +    sti->request_probe = 0;
> > +    sti->need_parsing = need_parsing;
> > +    sti->display_aspect_ratio = entry->dar;
> > +    sti->avctx->framerate = entry->framerate;
> > +
> > +    if (entry->has_cc)
> > +        sti->avctx->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS;
> > +
> > +    avpriv_set_pts_info(st, DVDVIDEO_PTS_WRAP_BITS,
> > +                        DVDVIDEO_TIME_BASE_Q.num,
> DVDVIDEO_TIME_BASE_Q.den);
> > +
> > +    return 0;
> > +}
> > +
> > +static int dvdvideo_video_stream_setup(AVFormatContext *s)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    DVDVideoVTSVideoStreamEntry *entry = NULL;
> > +    int ret = 0;
> > +
>
> > +    entry = av_mallocz(sizeof(DVDVideoVTSVideoStreamEntry));
>
> you might check for failure
>
> > +
> > +    if ((ret = dvdvideo_video_stream_analyze(s,
> c->vts_ifo->vtsi_mat->vts_video_attr, entry)) < 0
> > +            || (ret = dvdvideo_video_stream_add(c->mpeg_ctx, entry,
> AVSTREAM_PARSE_FULL)) < 0
> > +            || (ret = dvdvideo_video_stream_add(s, entry,
> AVSTREAM_PARSE_HEADERS)) < 0) {
> > +        av_freep(&entry);
>
> > +        av_log(s, AV_LOG_ERROR, "Unable to allocate video stream\n");
>
> misleading error message, I'd say: Unable to add video stream
>
> > +
> > +        return ret;
> > +    }
> > +
> > +    av_freep(&entry);
> > +
> > +    return ret;
> > +}
> > +
> > +static int dvdvideo_audio_stream_analyze(AVFormatContext *s,
> audio_attr_t audio_attr,
> > +                                         uint16_t audio_control,
> DVDVideoPGCAudioStreamEntry *entry)
> > +{
> > +    int startcode = 0;
> > +    enum AVCodecID codec_id = AV_CODEC_ID_NONE;
> > +    int sample_fmt = AV_SAMPLE_FMT_NONE;
> > +    int sample_rate = 0;
> > +    int bit_depth = 0;
> > +    int nb_channels = 0;
> > +    AVChannelLayout ch_layout = (AVChannelLayout) {0};
> > +    char lang_dvd[3] = {0};
> > +
> > +    int position = (audio_control & 0x7F00) >> 8;
> > +
> > +    /* XXX(PATCHWELCOME): SDDS is not supported due to lack of sample
> material */
> > +    switch (audio_attr.audio_format) {
> > +        case 0: /* AC3 */
> > +            codec_id = AV_CODEC_ID_AC3;
> > +            sample_fmt = AV_SAMPLE_FMT_FLTP;
> > +            sample_rate = 48000;
> > +            startcode = 0x80 + position;
> > +            break;
> > +        case 2: /* MP1 */
> > +            codec_id = AV_CODEC_ID_MP1;
> > +            sample_fmt = audio_attr.quantization ? AV_SAMPLE_FMT_S32 :
> AV_SAMPLE_FMT_S16;
> > +            sample_rate = 48000;
> > +            bit_depth = audio_attr.quantization ? 20 : 16;
> > +            startcode = 0x1C0 + position;
> > +            break;
> > +        case 3: /* MP2 */
> > +            codec_id = AV_CODEC_ID_MP2;
> > +            sample_fmt = audio_attr.quantization ? AV_SAMPLE_FMT_S32 :
> AV_SAMPLE_FMT_S16;
> > +            sample_rate = 48000;
> > +            bit_depth = audio_attr.quantization ? 20 : 16;
> > +            startcode = 0x1C0 + position;
> > +            break;
> > +        case 4: /* DVD PCM */
> > +            codec_id = AV_CODEC_ID_PCM_DVD;
> > +            sample_fmt = audio_attr.quantization ? AV_SAMPLE_FMT_S32 :
> AV_SAMPLE_FMT_S16;
> > +            sample_rate = audio_attr.sample_frequency ? 96000 : 48000;
> > +            bit_depth = audio_attr.quantization == 2 ? 24 :
> (audio_attr.quantization ? 20 : 16);
> > +            startcode = 0xA0 + position;
> > +            break;
> > +        case 6: /* DCA */
> > +            codec_id = AV_CODEC_ID_DTS;
> > +            sample_fmt = AV_SAMPLE_FMT_FLTP;
> > +            sample_rate = 48000;
> > +            bit_depth = audio_attr.quantization == 2 ? 24 :
> (audio_attr.quantization ? 20 : 16);
> > +            startcode = 0x88 + position;
> > +            break;
> > +    }
> > +
> > +    nb_channels = audio_attr.channels + 1;
> > +
> > +    if (codec_id == AV_CODEC_ID_NONE
> > +            || startcode == 0 || sample_fmt == AV_SAMPLE_FMT_NONE
> > +            || sample_rate == 0 || nb_channels == 0) {
>
> > +        av_log(s, AV_LOG_ERROR, "Invalid audio parameters\n");
>
> please provide some context to help debug impossible cases
>
> > +
> > +        return AVERROR_INVALIDDATA;
> > +    }
> > +
> > +    if (nb_channels == 2)
> > +        ch_layout = (AVChannelLayout) AV_CHANNEL_LAYOUT_STEREO;
> > +    else if (nb_channels == 6)
> > +        ch_layout = (AVChannelLayout) AV_CHANNEL_LAYOUT_5POINT1;
> > +    else if (nb_channels == 7)
> > +        ch_layout = (AVChannelLayout) AV_CHANNEL_LAYOUT_6POINT1;
> > +    else if (nb_channels == 8)
> > +        ch_layout = (AVChannelLayout) AV_CHANNEL_LAYOUT_7POINT1;
> > +
> > +    if (audio_attr.code_extension == 2)
> > +        entry->disposition |= AV_DISPOSITION_VISUAL_IMPAIRED;
> > +    if (audio_attr.code_extension == 3 || audio_attr.code_extension ==
> 4)
> > +        entry->disposition |= AV_DISPOSITION_COMMENT;
> > +
> > +    AV_WB16(lang_dvd, audio_attr.lang_code);
> > +
> > +    entry->startcode = startcode;
> > +    entry->codec_id = codec_id;
> > +    entry->sample_rate = sample_rate;
> > +    entry->bit_depth = bit_depth;
> > +    entry->nb_channels = nb_channels;
> > +    entry->ch_layout = ch_layout;
> > +    entry->lang_iso = (char *) ff_convert_lang_to(lang_dvd,
> AV_LANG_ISO639_2_BIBL);
> > +
> > +    return 0;
> > +}
> > +
> > +static int dvdvideo_audio_stream_add(AVFormatContext *s,
> DVDVideoPGCAudioStreamEntry *entry,
> > +                                     enum AVStreamParseType
> need_parsing)
> > +{
> > +    AVStream *st;
> > +    FFStream *sti;
> > +
> > +    st = avformat_new_stream(s, NULL);
> > +    if (!st)
> > +        return AVERROR(ENOMEM);
> > +
> > +    st->id = entry->startcode;
> > +    st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
> > +    st->codecpar->codec_id = entry->codec_id;
> > +    st->codecpar->format = entry->sample_fmt;
> > +    st->codecpar->sample_rate = entry->sample_rate;
> > +    st->codecpar->bits_per_coded_sample = entry->bit_depth;
> > +    st->codecpar->bits_per_raw_sample = entry->bit_depth;
> > +    st->codecpar->ch_layout = entry->ch_layout;
> > +    st->codecpar->ch_layout.nb_channels = entry->nb_channels;
> > +    st->disposition = entry->disposition;
> > +
> > +    if (entry->lang_iso)
> > +        av_dict_set(&st->metadata, "language", entry->lang_iso, 0);
> > +
> > +    sti = ffstream(st);
> > +    sti->request_probe = 0;
> > +    sti->need_parsing = need_parsing;
> > +
> > +    avpriv_set_pts_info(st, DVDVIDEO_PTS_WRAP_BITS,
> > +                        DVDVIDEO_TIME_BASE_Q.num,
> DVDVIDEO_TIME_BASE_Q.den);
> > +
> > +    return 0;
> > +}
> > +
> > +static int dvdvideo_audio_stream_add_all(AVFormatContext *s)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    int ret = 0;
> > +
> > +    for (int i = 0; i < c->vts_ifo->vtsi_mat->nr_of_vts_audio_streams;
> i++) {
> > +        DVDVideoPGCAudioStreamEntry *entry = NULL;
> > +
> > +        if (!(c->play_state.pgc->audio_control[i] & 0x8000))
> > +            continue;
> > +
> > +        entry = av_mallocz(sizeof(DVDVideoPGCAudioStreamEntry));
> > +        if (!entry)
> > +            return AVERROR(ENOMEM);
> > +
> > +        if ((ret = dvdvideo_audio_stream_analyze(s,
> c->vts_ifo->vtsi_mat->vts_audio_attr[i],
> > +                c->play_state.pgc->audio_control[i], entry)) < 0)
> > +            goto break_free_and_error;
> > +
> > +        if (c->vts_ifo->vtsi_mat->vts_audio_attr[i].application_mode ==
> 1)
> > +            av_log(s, AV_LOG_WARNING, "Karaoke metadata in stream %d
> will not be retained\n",
> > +                                      entry->startcode);
> > +
> > +        /* IFO structures can declare duplicate entries for the same
> startcode */
> > +        for (int j = 0; j < s->nb_streams; j++)
> > +            if (s->streams[j]->id == entry->startcode)
> > +                goto continue_free;
> > +
> > +        if ((ret = dvdvideo_audio_stream_add(c->mpeg_ctx, entry,
> AVSTREAM_PARSE_FULL)) < 0
> > +                || (ret = dvdvideo_audio_stream_add(s, entry,
> AVSTREAM_PARSE_HEADERS)) < 0)
> > +            goto break_free_and_error;
> > +
> > +continue_free:
> > +        av_freep(&entry);
> > +        continue;
> > +
> > +break_free_and_error:
> > +        av_freep(&entry);
>
> > +        av_log(s, AV_LOG_ERROR, "Unable to allocate audio stream\n");
>
> ditto: unable to "add" audio stream?
>
> > +        return ret;
> > +    }
> > +
> > +    return ret;
> > +}
> > +
> > +static int dvdvideo_subp_stream_analyze(AVFormatContext *s, uint32_t
> offset, subp_attr_t subp_attr,
> > +                                        DVDVideoPGCSubtitleStreamEntry
> *entry)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    char lang_dvd[3] = {0};
> > +
> > +    entry->startcode = 0x20 + (offset & 0x1F);
> > +
> > +    if (subp_attr.lang_extension == 9)
> > +        entry->disposition |= AV_DISPOSITION_FORCED;
> > +
> > +    AV_WB16(lang_dvd, subp_attr.lang_code);
> > +    entry->lang_iso = (char *) ff_convert_lang_to(lang_dvd,
> AV_LANG_ISO639_2_BIBL);
> > +
> > +    return 0;
> > +}
> > +
> > +static int dvdvideo_subp_stream_add(AVFormatContext *s,
> DVDVideoPGCSubtitleStreamEntry *entry,
> > +                                    enum AVStreamParseType need_parsing)
> > +{
> > +    AVStream *st;
> > +    FFStream *sti;
> > +    int ret = 0;
> > +
> > +    st = avformat_new_stream(s, NULL);
> > +    if (!st)
> > +        return AVERROR(ENOMEM);
> > +
> > +    st->id = entry->startcode;
> > +    st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
> > +    st->codecpar->codec_id = AV_CODEC_ID_DVD_SUBTITLE;
> > +
> > +    if (entry->lang_iso)
> > +        av_dict_set(&st->metadata, "language", entry->lang_iso, 0);
> > +
> > +    av_dict_set(&st->metadata, "VIEWPORT",
> VIEWPORT_LABELS[entry->viewport], 0);
> > +
> > +    st->disposition = entry->disposition;
> > +
> > +    sti = ffstream(st);
> > +    sti->request_probe = 0;
> > +    sti->need_parsing = need_parsing;
> > +
> > +    avpriv_set_pts_info(st, DVDVIDEO_PTS_WRAP_BITS,
> > +                        DVDVIDEO_TIME_BASE_Q.num,
> DVDVIDEO_TIME_BASE_Q.den);
> > +
> > +    return ret;
> > +}
> > +
> > +static int dvdvideo_subp_stream_add_internal(AVFormatContext *s,
> uint32_t offset,
> > +                                             subp_attr_t subp_attr,
> > +                                             enum
> DVDVideoSubpictureViewport viewport)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    DVDVideoPGCSubtitleStreamEntry *entry = NULL;
> > +    int ret = 0;
> > +
>
> > +    entry = av_mallocz(sizeof(DVDVideoPGCSubtitleStreamEntry));
>
> missing check
>
> > +    entry->viewport = viewport;
> > +
> > +    if ((ret = dvdvideo_subp_stream_analyze(s, offset, subp_attr,
> entry)) < 0)
> > +        goto end_free_error;
> > +
> > +    /* IFO structures can declare duplicate entries for the same
> startcode */
> > +    for (int i = 0; i < s->nb_streams; i++)
> > +        if (s->streams[i]->id == entry->startcode)
> > +            goto end_free;
> > +
> > +    if ((ret = dvdvideo_subp_stream_add(c->mpeg_ctx, entry,
> AVSTREAM_PARSE_FULL)) < 0
> > +            || (ret = dvdvideo_subp_stream_add(s, entry,
> AVSTREAM_PARSE_HEADERS)) < 0)
> > +        goto end_free_error;
> > +
> > +    goto end_free;
> > +
> > +end_free_error:
>
> > +    av_log(s, AV_LOG_ERROR, "Unable to allocate subtitle stream\n");
>
> ditto
>
> > +
> > +end_free:
> > +    av_freep(&entry);
> > +
> > +    return ret;
> > +}
> > +
> > +static int dvdvideo_subp_stream_add_all(AVFormatContext *s)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    if (!c->vts_ifo->vtsi_mat->nr_of_vts_subp_streams)
> > +        return 0;
> > +
> > +    for (int i = 0; i < c->vts_ifo->vtsi_mat->nr_of_vts_subp_streams;
> i++) {
> > +        int ret = 0;
> > +        uint32_t subp_control;
> > +        subp_attr_t subp_attr;
> > +        video_attr_t video_attr;
> > +
> > +        subp_control = c->play_state.pgc->subp_control[i];
> > +        if (!(subp_control & 0x80000000))
> > +            continue;
> > +
> > +        /* there can be several presentations for one SPU */
> > +        /* for now, be flexible with the DAR check due to weird
> authoring */
> > +        video_attr = c->vts_ifo->vtsi_mat->vts_video_attr;
> > +        subp_attr = c->vts_ifo->vtsi_mat->vts_subp_attr[i];
> > +
> > +        /* 4:3 */
> > +        if (!video_attr.display_aspect_ratio) {
> > +            if ((ret = dvdvideo_subp_stream_add_internal(s,
> subp_control >> 24, subp_attr,
> > +
>  DVDVIDEO_SUBP_VIEWPORT_FULLSCREEN)) < 0)
> > +                return ret;
> > +
> > +            continue;
> > +        }
> > +
> > +        /* 16:9 */
> > +        if ((ret = dvdvideo_subp_stream_add_internal(s, subp_control >>
> 16, subp_attr,
> > +
>  DVDVIDEO_SUBP_VIEWPORT_WIDESCREEN)) < 0)
> > +            return ret;
> > +
> > +        /* 16:9 letterbox */
> > +        if (video_attr.permitted_df == 2 || video_attr.permitted_df ==
> 0)
> > +            if ((ret = dvdvideo_subp_stream_add_internal(s,
> subp_control >> 8, subp_attr,
> > +
>  DVDVIDEO_SUBP_VIEWPORT_LETTERBOX)) < 0)
> > +                return ret;
> > +
> > +        /* 16:9 pan-and-scan */
> > +        if (video_attr.permitted_df == 1 || video_attr.permitted_df ==
> 0)
> > +            if ((ret = dvdvideo_subp_stream_add_internal(s,
> subp_control, subp_attr,
> > +
>  DVDVIDEO_SUBP_VIEWPORT_PANSCAN)) < 0)
> > +                return ret;
> > +    }
> > +
> > +    return 0;
> > +}
> > +
> > +static void dvdvideo_subdemux_flush(AVFormatContext *s)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    if (!c->play_seg_started)
> > +        return;
> > +
> > +    av_log(s, AV_LOG_DEBUG, "flushing sub-demuxer\n");
> > +    avio_flush(&c->mpeg_pb.pub);
> > +    ff_read_frame_flush(c->mpeg_ctx);
> > +    c->play_seg_started = 0;
> > +}
> > +
> > +static int dvdvideo_subdemux_read_data(void *opaque, uint8_t *buf, int
> buf_size)
> > +{
> > +    AVFormatContext *s = opaque;
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    int ret = 0;
> > +    int nav_event;
> > +
> > +    if (c->play_end)
> > +        return AVERROR_EOF;
> > +
> > +    ret = dvdvideo_play_next_ps_block(opaque, &c->play_state, buf,
> buf_size,
> > +                                      &nav_event,
> dvdvideo_subdemux_flush);
> > +
> > +    if (ret == AVERROR_EOF) {
> > +        c->mpeg_pb.pub.eof_reached = 1;
> > +        c->play_end = 1;
> > +
> > +        return AVERROR_EOF;
> > +    }
> > +
> > +    if (ret >= 0 && nav_event == DVDNAV_NAV_PACKET)
> > +        return FFERROR_REDO;
> > +
> > +    return ret;
> > +}
> > +
> > +static void dvdvideo_subdemux_close(AVFormatContext *s)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    av_freep(&c->mpeg_pb.pub.buffer);
> > +    av_freep(&c->mpeg_pb);
> > +    avformat_close_input(&c->mpeg_ctx);
> > +}
> > +
> > +static int dvdvideo_subdemux_open(AVFormatContext *s)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    int ret = 0;
> > +
> > +    if (!(c->mpeg_fmt = av_find_input_format("mpeg")))
> > +        return AVERROR_DEMUXER_NOT_FOUND;
> > +
> > +    if (!(c->mpeg_ctx = avformat_alloc_context()))
> > +        return AVERROR(ENOMEM);
> > +
> > +    if (!(c->mpeg_buf = av_mallocz(DVDVIDEO_BLOCK_SIZE))) {
> > +        avformat_free_context(c->mpeg_ctx);
> > +
> > +        return AVERROR(ENOMEM);
> > +    }
> > +
> > +    ffio_init_context(&c->mpeg_pb, c->mpeg_buf, DVDVIDEO_BLOCK_SIZE, 0,
> s,
> > +                      dvdvideo_subdemux_read_data, NULL, NULL);
> > +    c->mpeg_pb.pub.seekable = 0;
> > +
> > +    if ((ret = ff_copy_whiteblacklists(c->mpeg_ctx, s)) < 0) {
> > +        avformat_free_context(c->mpeg_ctx);
> > +
> > +        return ret;
> > +    }
> > +
> > +    c->mpeg_ctx->flags = AVFMT_FLAG_CUSTOM_IO | AVFMT_FLAG_GENPTS;
> > +    c->mpeg_ctx->ctx_flags |= AVFMTCTX_UNSEEKABLE;
> > +    c->mpeg_ctx->probesize = 0;
> > +    c->mpeg_ctx->max_analyze_duration = 0;
> > +    c->mpeg_ctx->interrupt_callback = s->interrupt_callback;
> > +    c->mpeg_ctx->pb = &c->mpeg_pb.pub;
> > +    c->mpeg_ctx->io_open = NULL;
> > +
> > +    if ((ret = avformat_open_input(&c->mpeg_ctx, "", c->mpeg_fmt,
> NULL)) < 0) {
> > +        avformat_free_context(c->mpeg_ctx);
> > +
> > +        return ret;
>
> you can drop this
>
> > +    }
> > +
> > +    return ret;
> > +}
> > +
> > +static int dvdvideo_read_header(AVFormatContext *s)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    int ret = 0;
> > +
> > +    if (c->opt_title == 0) {
> > +        av_log(s, AV_LOG_INFO, "Defaulting to title #1. "
> > +                               "This is not always the main feature,
> validation suggested.\n");
> > +
> > +        c->opt_title = 1;
> > +    }
> > +
> > +    if (c->opt_pgc) {
> > +        if (c->opt_pg == 0)
> > +            av_log(s, AV_LOG_ERROR, "Invalid coordinates. If -pgc is
> set, -pg must be set too.\n");
> > +        else if (c->opt_chapter_start > 1 || c->opt_chapter_end > 0 ||
> c->opt_preindex)
> > +            av_log(s, AV_LOG_ERROR, "-pgc is not compatible with the
> -preindex or "
> > +                                    "-chapter_start/-chapter_end
> options\n");
> > +
> > +        return AVERROR(EINVAL);
> > +    }
> > +
> > +    if ((ret = dvdvideo_ifo_open(s)) < 0)
> > +        return ret;
> > +
> > +    if (c->opt_preindex && (ret = dvdvideo_pgc_preindex(s)) < 0)
> > +        return ret;
> > +
> > +    if ((ret = dvdvideo_play_open(s, &c->play_state)) < 0
> > +            || (ret = dvdvideo_subdemux_open(s)) < 0
> > +            || (ret = dvdvideo_video_stream_setup(s)) < 0
> > +            || (ret = dvdvideo_audio_stream_add_all(s)) < 0
> > +            || (ret = dvdvideo_subp_stream_add_all(s)) < 0)
> > +        return ret;
> > +
> > +    if (!c->opt_preindex)
> > +        return dvdvideo_pgc_chapters_setup(s);
> > +
> > +    return ret;
> > +}
> > +
> > +static int dvdvideo_read_packet(AVFormatContext *s, AVPacket *pkt)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    int ret;
> > +    enum AVMediaType st_type;
> > +    int64_t cur_delta = 0;
> > +
> > +    if (c->play_end)
> > +        return AVERROR_EOF;
> > +
> > +    ret = av_read_frame(c->mpeg_ctx, pkt);
> > +
> > +    if (ret < 0)
> > +        return ret;
> > +
> > +    if (!c->play_seg_started)
> > +        c->play_seg_started = 1;
> > +
> > +    if (pkt->stream_index >= s->nb_streams) {
>
> > +        av_log(s, AV_LOG_DEBUG, "discarding frame with unknown
> stream\n");
>
> print the unrecongnized stream index
>
> > +        goto skip_redo;
> > +    }
> > +
> > +    st_type =
> c->mpeg_ctx->streams[pkt->stream_index]->codecpar->codec_type;
> > +
> > +    if (!c->play_started) {
> > +        if (st_type != AVMEDIA_TYPE_VIDEO || pkt->pts == AV_NOPTS_VALUE
> > +                                          || pkt->dts == AV_NOPTS_VALUE
> > +                                          || !(pkt->flags &
> AV_PKT_FLAG_KEY)) {
>
> > +            av_log(s, AV_LOG_DEBUG, "discarding non-video-keyframe at
> start\n");
>
> of packet with unset PTS/DTS at start
>
> > +            goto skip_redo;
> > +        }
> > +
> > +        c->first_pts = pkt->pts;
> > +        c->play_started = 1;
> > +
> > +        pkt->pts = 0;
> > +        pkt->dts = c->play_state.ts_offset - pkt->pts;
> > +    } else {
> > +        cur_delta = c->play_state.ts_offset - c->first_pts;
> > +
> > +        if (c->play_state.nb_vobus_played == 1 && (pkt->pts ==
> AV_NOPTS_VALUE
> > +                                               ||  pkt->dts ==
> AV_NOPTS_VALUE
> > +                                               || (pkt->pts +
> cur_delta) < 0)) {
> > +            av_log(s, AV_LOG_DEBUG, "discarding frame with negative or
> unset timestamp "
> > +                                    "(this is OK at the start of the
> first playback VOBU)\n");
> > +            goto skip_redo;
> > +        }
> > +
> > +        if (pkt->pts != AV_NOPTS_VALUE)
> > +            pkt->pts += cur_delta;
> > +        if (pkt->dts != AV_NOPTS_VALUE)
> > +            pkt->dts += cur_delta;
> > +    }
> > +
> > +    av_log(s, AV_LOG_TRACE, "st=%d pts=%ld dts=%ld ts_offset=%ld
> first_pts=%ld\n",
> > +                            pkt->stream_index, pkt->pts, pkt->dts,
> > +                            c->play_state.ts_offset, c->first_pts);
> > +    if (pkt->pts < 0)
> > +        av_log(s, AV_LOG_WARNING, "Invalid frame PTS @ st=%d pts=%ld
> dts=%ld\n",
> > +                                  pkt->stream_index, pkt->pts,
> pkt->dts);
> > +
> > +    return c->play_end ? AVERROR_EOF : 0;
> > +
> > +skip_redo:
> > +    av_packet_unref(pkt);
> > +    return FFERROR_REDO;
> > +}
> > +
> > +static int dvdvideo_close(AVFormatContext *s)
> > +{
> > +    DVDVideoDemuxContext *c = s->priv_data;
> > +
> > +    dvdvideo_subdemux_close(s);
> > +    dvdvideo_play_close(s, &c->play_state);
> > +    dvdvideo_ifo_close(s);
> > +
> > +    return 0;
> > +}
> > +
> > +#define OFFSET(x) offsetof(DVDVideoDemuxContext, x)
> > +static const AVOption dvdvideo_options[] = {
> > +    {"angle",           "playback angle number",
>             OFFSET(opt_angle),          AV_OPT_TYPE_INT,    { .i64=1 },
>  1,          9,         AV_OPT_FLAG_DECODING_PARAM },
> > +    {"chapter_end",     "exit chapter (PTT) number (0=end)",
>             OFFSET(opt_chapter_end),    AV_OPT_TYPE_INT,    { .i64=0 },
>  0,          99,        AV_OPT_FLAG_DECODING_PARAM },
> > +    {"chapter_start",   "entry chapter (PTT) number",
>              OFFSET(opt_chapter_start),  AV_OPT_TYPE_INT,    { .i64=1 },
>  1,          99,        AV_OPT_FLAG_DECODING_PARAM },
> > +    {"pg",              "entry PG number (0=auto)",
>              OFFSET(opt_pg),             AV_OPT_TYPE_INT,    { .i64=0 },
>  0,          255,       AV_OPT_FLAG_DECODING_PARAM },
> > +    {"pgc",             "entry PGC number (0=auto)",
>             OFFSET(opt_pgc),            AV_OPT_TYPE_INT,    { .i64=0 },
>  0,          999,       AV_OPT_FLAG_DECODING_PARAM },
> > +    {"preindex",        "enable for accurate chapter markers, slow
> (2-pass read)",  OFFSET(opt_preindex),       AV_OPT_TYPE_BOOL,   { .i64=0
> },     0,          1,         AV_OPT_FLAG_DECODING_PARAM },
> > +    {"region",          "playback region number (0=free)",
>             OFFSET(opt_region),         AV_OPT_TYPE_INT,    { .i64=0 },
>  0,          8,         AV_OPT_FLAG_DECODING_PARAM },
> > +    {"title",           "title number (0=auto)",
>             OFFSET(opt_title),          AV_OPT_TYPE_INT,    { .i64=0 },
>  0,          99,        AV_OPT_FLAG_DECODING_PARAM },
> > +    {"trim",            "trim padding cells from start",
>             OFFSET(opt_trim),           AV_OPT_TYPE_BOOL,   { .i64=1 },
>  0,          1,         AV_OPT_FLAG_DECODING_PARAM },
> > +    {NULL}
> > +};
> > +
> > +static const AVClass dvdvideo_class = {
> > +    .class_name = "DVD-Video demuxer",
> > +    .item_name  = av_default_item_name,
> > +    .option     = dvdvideo_options,
> > +    .version    = LIBAVUTIL_VERSION_INT
> > +};
> > +
> > +const AVInputFormat ff_dvdvideo_demuxer = {
> > +    .name           = "dvdvideo",
> > +    .long_name      = NULL_IF_CONFIG_SMALL("DVD-Video"),
> > +    .priv_class     = &dvdvideo_class,
> > +    .priv_data_size = sizeof(DVDVideoDemuxContext),
> > +    .flags          = AVFMT_NOFILE | AVFMT_SHOW_IDS | AVFMT_TS_DISCONT
> | AVFMT_NO_BYTE_SEEK | AVFMT_NOGENSEARCH | AVFMT_NOBINSEARCH,
> > +    .flags_internal = FF_FMT_INIT_CLEANUP,
> > +    .read_close     = dvdvideo_close,
> > +    .read_header    = dvdvideo_read_header,
> > +    .read_packet    = dvdvideo_read_packet
> > +};
>
> LGTM otherwise, thanks.
>

Marth64:
> Sorry for the quick follow-up to v6, I wanted to get this update out now hopefully
> before v6 is actually reviewed. v7 fixes a few documentation typos, options descriptions,
> and log messages: nothing major. I also flattened this out to be a 2-patch set
> with subtitle palette support.
> 
> This is the result of >1yr of research and I am now very satisfied with it's result.
> I will not make any more changes at this point unless it is outcome from a review.
> If the community decides to merge it, I am happy to continue to improve it with support for
> seeking, probing, and tests.
> 
> Thank you so much,
> 
> 
> Signed-off-by: Marth64 <marth64@proxyid.net>
> ---
>  Changelog                 |    2 +
>  configure                 |    8 +
>  doc/demuxers.texi         |  129 ++++
>  libavformat/Makefile      |    1 +
>  libavformat/allformats.c  |    1 +
>  libavformat/dvdvideodec.c | 1410 +++++++++++++++++++++++++++++++++++++
>  6 files changed, 1551 insertions(+)
>  create mode 100644 libavformat/dvdvideodec.c
> 
> diff --git a/Changelog b/Changelog
> index c5fb21d198..88653bc6d3 100644
> --- a/Changelog
> +++ b/Changelog
> @@ -24,6 +24,8 @@ version <next>:
>  - ffmpeg CLI options may now be used as -/opt <path>, which is equivalent
>    to -opt <contents of file <path>>
>  - showinfo bitstream filter
> +- DVD-Video demuxer, powered by libdvdnav and libdvdread
> +
>  
>  version 6.1:
>  - libaribcaption decoder
> diff --git a/configure b/configure
> index 68f675a4bc..70c33ec96d 100755
> --- a/configure
> +++ b/configure
> @@ -227,6 +227,8 @@ External library support:
>    --enable-libdavs2        enable AVS2 decoding via libdavs2 [no]
>    --enable-libdc1394       enable IIDC-1394 grabbing using libdc1394
>                             and libraw1394 [no]
> +  --enable-libdvdnav       enable libdvdnav, needed for DVD demuxing [no]
> +  --enable-libdvdread      enable libdvdread, needed for DVD demuxing [no]
>    --enable-libfdk-aac      enable AAC de/encoding via libfdk-aac [no]
>    --enable-libflite        enable flite (voice synthesis) support via libflite [no]
>    --enable-libfontconfig   enable libfontconfig, useful for drawtext filter [no]
> @@ -1806,6 +1808,8 @@ EXTERNAL_LIBRARY_GPL_LIST="
>      frei0r
>      libcdio
>      libdavs2
> +    libdvdnav
> +    libdvdread
>      librubberband
>      libvidstab
>      libx264
> @@ -3520,6 +3524,8 @@ dts_demuxer_select="dca_parser"
>  dtshd_demuxer_select="dca_parser"
>  dv_demuxer_select="dvprofile"
>  dv_muxer_select="dvprofile"
> +dvdvideo_demuxer_select="mpegps_demuxer"
> +dvdvideo_demuxer_deps="libdvdnav libdvdread"
>  dxa_demuxer_select="riffdec"
>  eac3_demuxer_select="ac3_parser"
>  evc_demuxer_select="evc_frame_merge_bsf evc_parser"
> @@ -6761,6 +6767,8 @@ enabled libdav1d          && require_pkg_config libdav1d "dav1d >= 0.5.0" "dav1d
>  enabled libdavs2          && require_pkg_config libdavs2 "davs2 >= 1.6.0" davs2.h davs2_decoder_open
>  enabled libdc1394         && require_pkg_config libdc1394 libdc1394-2 dc1394/dc1394.h dc1394_new
>  enabled libdrm            && check_pkg_config libdrm libdrm xf86drm.h drmGetVersion
> +enabled libdvdnav         && require_pkg_config libdvdnav "dvdnav >= 6.1.1" dvdnav/dvdnav.h dvdnav_open2
> +enabled libdvdread        && require_pkg_config libdvdread "dvdread >= 6.1.2" dvdread/dvd_reader.h DVDOpen2 -ldvdread
>  enabled libfdk_aac        && { check_pkg_config libfdk_aac fdk-aac "fdk-aac/aacenc_lib.h" aacEncOpen ||
>                                 { require libfdk_aac fdk-aac/aacenc_lib.h aacEncOpen -lfdk-aac &&
>                                   warn "using libfdk without pkg-config"; } }
> diff --git a/doc/demuxers.texi b/doc/demuxers.texi
> index e4c5b560a6..ad0906f6ec 100644
> --- a/doc/demuxers.texi
> +++ b/doc/demuxers.texi
> @@ -285,6 +285,135 @@ This demuxer accepts the following option:
>  
>  @end table
>  
> +@section dvdvideo
> +
> +DVD-Video demuxer, powered by libdvdnav and libdvdread.
> +
> +Can directly ingest DVD titles, specifically sequential PGCs,
> +into a conversion pipeline. Menus and seeking are not supported at this time.
> +
> +Block devices (DVD drives), ISO files, and directory structures are accepted.
> +Activate with @code{-f dvdvideo} in front of one of these inputs.
> +
> +Underlying playback is fully handled by libdvdnav, and structure parsing by libdvdread.
> +ffmpeg must be built with GPL library support available as well as the switches
> +@code{--enable-libdvdnav} and @code{--enable-libdvdread}.
> +
> +You will need to provide either the desired "title number" or exact PGC/PG coordinates.
> +Many open-source DVD players and tools can aid in providing this information.
> +If not specified, the demuxer will default to title 1 which works for many discs.
> +However, due to the flexibility of DVD-Video, it is recommended to check manually.
> +There are many discs that are authored strangely or with invalid headers.
> +
> +If the input is a real DVD drive, please note that there are some drives which may
> +silently fail on reading bad sectors from the disc, returning random bits instead
> +which is effectively corrupt data. This is especially prominent on aging or rotting discs.
> +A second pass and integrity checks would be needed to detect the corruption.
> +This is not an ffmpeg issue.
> +
> +@subsection Background
> +
> +DVD-Video is not a directly accessible, linear container format in the
> +traditional sense. Instead, it allows for complex and programmatic playback of
> +carefully muxed MPEG-PS streams that are stored in headerless VOB files.
> +To the end-user, these streams are known simply as "titles", but the actual
> +logical playback sequence is defined by one or more "PGCs", or Program Group Chains,
> +within the title. The PGC is in turn comprised of multiple "PGs", or Programs",
> +which are the actual video segments which, for a typical movie, are sequentially
> +ordered. The PGC structure, along with stream layout and metadata, are stored in
> +IFO files that need to be parsed. PGCs can be thought of as playlists in easier terms.
> +
> +An actual DVD player relies on user GUI interaction via menus and an internal VM
> +to drive the direction of demuxing. Generally, the user would either navigate (via menus)
> +or automatically be redirected to the PGC of their choice. During this process and
> +the subsequent playback, the DVD player's internal VM also maintains a state and
> +executes instructions that can create jumps to different sectors during playback.
> +This is why libdvdnav is involved, as a linear read of the MPEG-PS blobs on the
> +disc (VOBs) is not enough to produce the right sequence in many cases.
> +
> +There are many other DVD structures (a long subject) that will not be discussed here.
> +NAV packets, in particular, are handled by this demuxer to build accurate timing
> +but not emitted as a stream. For a good high-level understanding, refer to:
> +@url{https://code.videolan.org/videolan/libdvdnav/-/blob/master/doc/dvd_structures}
> +
> +@subsection Options
> +
> +This demuxer accepts the following options:
> +
> +@table @option
> +
> +@item title
> +The title number to play. Must be set if @option{pgc} and @option{pg} are not set.
> +Default is 0 (auto), which currently only selects the first available title (title 1)
> +and notifies the user about the implications.
> +
> +@item chapter_start
> +The chapter, or PTT (part-of-title), number to start at. Default is 1.
> +
> +@item chapter_end
> +The chapter, or PTT (part-of-title), number to end at. Default is 0,
> +which is a special value to signal end at the last possible chapter.
> +
> +@item angle
> +The video angle number, referring to what is essentially an additional
> +video stream that is composed from alternate frames interleaved in the VOBs.
> +Default is 1.
> +
> +@item region
> +The region code to use for playback. Some discs may use this to default playback
> +at a particular angle in different regions. This option will not affect the region code
> +of a real DVD drive, if used as an input. Default is 0, "world".
> +
> +@item pgc
> +The entry PGC to start playback, in conjunction with @option{pg}.
> +Alternative to setting @option{title}.
> +Chapter markers not supported at this time.
> +Default is 0, automatically resolve from value of @option{title}.
> +
> +@item pg
> +The entry PG to start playback, in conjunction with @option{pgc}.
> +Alternative to setting @option{title}.
> +Chapter markers not supported at this time.
> +Default is 0, automatically resolve from value of @option{title}.
> +
> +@item preindex
> +Enable this to have accurate chapter (PTT) markers and duration measurement,
> +which requires a slow second pass read in order to index the chapter
> +timestamps from NAV packets. This is non-ideal extra work for physical DVD drives.
> +Not compatible with @option{pgc} and @option{pg}.
> +Default is 0, false.
> +
> +@item trim
> +Skip padding cells (i.e. cells shorter than 1 second) from the beginning.
> +There exist many discs with filler segments at the beginning of the PGC,
> +often with junk data intended for controlling a real DVD player's
> +buffering speed and with no other material data value.
> +Default is 1, true.
> +
> +@end table
> +
> +@subsection Examples
> +
> +@itemize
> +@item
> +Open title 3 from a given DVD structure:
> +@example
> +ffmpeg -f dvdvideo -title 3 -i <path to DVD> ...
> +@end example
> +
> +@item
> +Open chapters 3-6 from title 1 from a given DVD structure:
> +@example
> +ffmpeg -f dvdvideo -chapter_start 3 -chapter_end 6 -title 1 -i <path to DVD> ...
> +@end example
> +
> +@item
> +Open only chapter 5 from title 1 from a given DVD structure:
> +@example
> +ffmpeg -f dvdvideo -chapter_start 5 -chapter_end 5 -title 1 -i <path to DVD> ...
> +@end example
> +@end itemize
> +
>  @section ea
>  
>  Electronic Arts Multimedia format demuxer.
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index 05b9b8a115..df69734877 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -192,6 +192,7 @@ OBJS-$(CONFIG_DTS_MUXER)                 += rawenc.o
>  OBJS-$(CONFIG_DV_MUXER)                  += dvenc.o
>  OBJS-$(CONFIG_DVBSUB_DEMUXER)            += dvbsub.o rawdec.o
>  OBJS-$(CONFIG_DVBTXT_DEMUXER)            += dvbtxt.o rawdec.o
> +OBJS-$(CONFIG_DVDVIDEO_DEMUXER)          += dvdvideodec.o
>  OBJS-$(CONFIG_DXA_DEMUXER)               += dxa.o
>  OBJS-$(CONFIG_EA_CDATA_DEMUXER)          += eacdata.o
>  OBJS-$(CONFIG_EA_DEMUXER)                += electronicarts.o
> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> index b04b43cab3..3e905c23f8 100644
> --- a/libavformat/allformats.c
> +++ b/libavformat/allformats.c
> @@ -150,6 +150,7 @@ extern const AVInputFormat  ff_dv_demuxer;
>  extern const FFOutputFormat ff_dv_muxer;
>  extern const AVInputFormat  ff_dvbsub_demuxer;
>  extern const AVInputFormat  ff_dvbtxt_demuxer;
> +extern const AVInputFormat  ff_dvdvideo_demuxer;
>  extern const AVInputFormat  ff_dxa_demuxer;
>  extern const AVInputFormat  ff_ea_demuxer;
>  extern const AVInputFormat  ff_ea_cdata_demuxer;
> diff --git a/libavformat/dvdvideodec.c b/libavformat/dvdvideodec.c
> new file mode 100644
> index 0000000000..2e363a4a22
> --- /dev/null
> +++ b/libavformat/dvdvideodec.c
> @@ -0,0 +1,1410 @@
> +/*
> + * DVD-Video demuxer, powered by libdvdnav and libdvdread
> + *
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * FFmpeg is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with FFmpeg; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +/*
> + * See doc/demuxers.texi for a high-level overview.
> + *
> + * The tactical approach is as follows:
> + * 1) Open the volume with dvdread
> + * 2) Analyze the user-requested title and PGC coordinates in the IFO structures
> + * 3) Request playback at the coordinates and chosen angle with dvdnav
> + * 5) Begin the playback (reading and demuxing) of MPEG-PS blocks
> + * 6) End playback if navigation goes backwards, to a menu, or a different PGC or angle
> + * 7) Close the dvdnav VM, and free dvdread's IFO structures
> + */
> +
> +#include <dvdnav/dvdnav.h>
> +#include <dvdread/dvd_reader.h>
> +#include <dvdread/ifo_read.h>
> +#include <dvdread/ifo_types.h>
> +#include <dvdread/nav_read.h>
> +
> +#include "libavcodec/avcodec.h"

Seems unused.

> +#include "libavutil/avstring.h"
> +#include "libavutil/avutil.h"
> +#include "libavutil/intreadwrite.h"
> +#include "libavutil/mem.h"
> +#include "libavutil/opt.h"
> +#include "libavutil/samplefmt.h"
> +#include "libavutil/time.h"
> +#include "libavutil/timestamp.h"
> +
> +#include "avformat.h"
> +#include "avio_internal.h"
> +#include "avlanguage.h"
> +#include "demux.h"
> +#include "internal.h"
> +#include "url.h"

What is this header used for?

> +
> +#define DVDVIDEO_MAX_PS_SEARCH_BLOCKS                   128
> +#define DVDVIDEO_BLOCK_SIZE                             2048
> +#define DVDVIDEO_TIME_BASE_Q                            (AVRational) { 1, 90000 }
> +#define DVDVIDEO_PTS_WRAP_BITS                          64 /* VOBUs use 32 (PES allows 33) */
> +#define DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE                1024
> +
> +enum DVDVideoSubpictureViewport {
> +    DVDVIDEO_SUBP_VIEWPORT_FULLSCREEN,
> +    DVDVIDEO_SUBP_VIEWPORT_WIDESCREEN,
> +    DVDVIDEO_SUBP_VIEWPORT_LETTERBOX,
> +    DVDVIDEO_SUBP_VIEWPORT_PANSCAN
> +};
> +const char* VIEWPORT_LABELS[4] = { "Fullscreen", "Widescreen", "Letterbox", "Pan and Scan" };

1. Should be static.
2. No uppercase names; and the '*' should be put at the variable name,
not the type (int* a,b declares a as pointer to int and b as int!).
3. No relocations, please: static const char viewport_labels[4][13].

> +
> +typedef struct DVDVideoVTSVideoStreamEntry {
> +    int startcode;
> +    enum AVCodecID codec_id;
> +    int width;
> +    int height;
> +    AVRational dar;
> +    AVRational framerate;
> +    int has_cc;
> +} DVDVideoVTSVideoStreamEntry;
> +
> +typedef struct DVDVideoPGCAudioStreamEntry {
> +    int startcode;
> +    enum AVCodecID codec_id;
> +    int sample_fmt;
> +    int sample_rate;
> +    int bit_depth;
> +    int nb_channels;
> +    AVChannelLayout ch_layout;
> +    int disposition;
> +    char *lang_iso;

Should be const

> +} DVDVideoPGCAudioStreamEntry;
> +
> +typedef struct DVDVideoPGCSubtitleStreamEntry {
> +    int startcode;
> +    int disposition;
> +    char *lang_iso;

Should be const

> +    enum DVDVideoSubpictureViewport viewport;
> +} DVDVideoPGCSubtitleStreamEntry;
> +
> +typedef struct DVDVideoPlaybackState {
> +    int                         celln;              /* ID of the active cell */
> +    int                         entry_pgn;          /* ID of the PG we are starting in */
> +    int                         in_pgc;             /* if our navigator is in the PGC */
> +    int                         in_ps;              /* if our navigator is in the program stream */
> +    int                         in_vts;             /* if our navigator is in the VTS */
> +    int64_t                     nav_pts;            /* PTS according to IFO, not frame-accurate */
> +    int                         nb_vobus_played;    /* number of VOBUs played back so far */
> +    uint64_t                    pgc_duration_est;   /* estimated duration as reported by IFO */
> +    uint64_t                    pgc_elapsed;        /* the elapsed time of the PGC, cell-relative */
> +    int                         pgc_nb_pg_est;      /* number of PGs as reported by IFOs */
> +    int                         pgcn;               /* ID of the PGC we are playing */
> +    int                         pgn;                /* ID of the PG we are in now */
> +    int                         ptt;                /* ID of the chapter we are in now */
> +    int64_t                     ts_offset;          /* PTS discontinuity offset (ex. VOB change) */
> +    uint32_t                    vobu_duration;      /* duration of the current VOBU */
> +    uint32_t                    vobu_e_ptm;         /* end PTS of the current VOBU */
> +    int                         vtsn;               /* ID of the active VTS (video title set) */
> +    uint64_t                    *pgc_pg_times_est;  /* PG start times as reported by IFO */
> +    pgc_t                       *pgc;               /* handle to the active PGC */
> +    dvdnav_t                    *dvdnav;            /* handle to libdvdnav */
> +} DVDVideoPlaybackState;
> +
> +typedef struct DVDVideoDemuxContext {
> +    const AVClass               *class;
> +
> +    /* options */
> +    int                         opt_title;          /* the user-provided title number (1-indexed) */
> +    int                         opt_chapter_start;  /* the user-provided entry PTT (1-indexed) */
> +    int                         opt_chapter_end;    /* the user-provided exit PTT (0 for last) */
> +    int                         opt_pgc;            /* the user-provided PGC number (1-indexed) */
> +    int                         opt_pg;             /* the user-provided PG number (1-indexed) */
> +    int                         opt_angle;          /* the user-provided angle number (1-indexed) */
> +    int                         opt_region;         /* the user-provided region digit */
> +    int                         opt_preindex;       /* pre-indexing mode (2-pass read) */
> +    int                         opt_trim;           /* trim padding cells at beginning and end */
> +
> +    /* subdemux */
> +    const AVInputFormat         *mpeg_fmt;          /* inner MPEG-PS (VOB) demuxer */
> +    AVFormatContext             *mpeg_ctx;          /* context for inner demuxer */
> +    uint8_t                     *mpeg_buf;          /* buffer for inner demuxer */
> +    FFIOContext                 mpeg_pb;            /* buffer context for inner demuxer */
> +
> +    /* volume */
> +    dvd_reader_t                *dvdread;           /* handle to libdvdread */
> +    ifo_handle_t                *vmg_ifo;           /* handle to the VMG (VIDEO_TS.IFO) */
> +    ifo_handle_t                *vts_ifo;           /* handle to the active VTS (VTS_nn_n.IFO) */
> +
> +    /* playback control */
> +    int                         play_end;           /* signal EOF to the parent demuxer */
> +    DVDVideoPlaybackState       play_state;         /* the active playback state */
> +    int                         play_started;       /* signal that playback has started */
> +    int                         play_seg_started;   /* signal that segment has started */
> +    int64_t                     first_pts;          /* the starting PTS offset of the PGC */
> +    uint64_t                    duration_ptm;       /* total duration in DVD MPEG timebase */
> +} DVDVideoDemuxContext;
> +
> +static void dvdvideo_libdvdread_log(void *opaque, dvd_logger_level_t level,
> +                                    const char *msg, va_list msg_va)
> +{
> +    AVFormatContext *s = opaque;
> +    int lavu_level;
> +
> +    char msg_buf[DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE] = {0};

This initialization is unnecessary, as vsnprintf works with
uninitialized buffers and zero-terminates them on its own.

> +    vsnprintf(msg_buf, DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE, msg, msg_va);

Should use sizeof(msf_buf). Same for the other log callback.

> +
> +    switch (level) {
> +        case DVD_LOGGER_LEVEL_ERROR:
> +            lavu_level = AV_LOG_ERROR;
> +            break;
> +        case DVD_LOGGER_LEVEL_WARN:
> +            lavu_level = AV_LOG_WARNING;
> +            break;
> +        /* dvdread's info messages are relatively very verbose, muffle them as debug */
> +        case DVD_LOGGER_LEVEL_INFO:
> +        case DVD_LOGGER_LEVEL_DEBUG:
> +        default:
> +            lavu_level = AV_LOG_DEBUG;
> +    }
> +
> +    av_log(s, lavu_level, "libdvdread: %s\n", msg_buf);
> +}
> +
> +static void dvdvideo_libdvdnav_log(void *opaque, dvdnav_logger_level_t level,
> +                                   const char *msg, va_list msg_va)
> +{
> +    AVFormatContext *s = opaque;
> +    int lavu_level;
> +
> +    char msg_buf[DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE] = {0};
> +    vsnprintf(msg_buf, DVDVIDEO_LIBDVDX_LOG_BUFFER_SIZE, msg, msg_va);
> +
> +    switch (level) {
> +        case DVDNAV_LOGGER_LEVEL_ERROR:
> +            lavu_level = AV_LOG_ERROR;
> +            break;
> +        case DVDNAV_LOGGER_LEVEL_WARN:
> +            /* some discs have invalid language codes set for their menus, muffle the noise */
> +            lavu_level = av_strstart(msg, "Language", NULL) ? AV_LOG_DEBUG : AV_LOG_WARNING;
> +            break;
> +        /* dvdnav's info messages are relatively very verbose, muffle them as debug */
> +        case DVDNAV_LOGGER_LEVEL_INFO:
> +        case DVDNAV_LOGGER_LEVEL_DEBUG:
> +        default:
> +            lavu_level = AV_LOG_DEBUG;
> +    }
> +
> +    av_log(s, lavu_level, "libdvdnav: %s\n", msg_buf);
> +}

Please refactor the common code of these loggers.

> +
> +static void dvdvideo_ifo_close(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    if (c->vts_ifo)
> +        ifoClose(c->vts_ifo);
> +
> +    if (c->vmg_ifo)
> +        ifoClose(c->vmg_ifo);
> +
> +    if (c->dvdread)
> +        DVDClose(c->dvdread);
> +}
> +
> +static int dvdvideo_ifo_open(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    dvd_logger_cb dvdread_log_cb;
> +    title_info_t title_info;
> +
> +    dvdread_log_cb = (dvd_logger_cb) { .pf_log = dvdvideo_libdvdread_log };
> +    c->dvdread = DVDOpen2(s, &dvdread_log_cb, s->url);
> +
> +    if (!c->dvdread) {
> +        av_log(s, AV_LOG_ERROR, "Unable to open the DVD-Video structure\n");
> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    if (!(c->vmg_ifo = ifoOpen(c->dvdread, 0))) {
> +        av_log(s, AV_LOG_ERROR, "Unable to open the VMG (VIDEO_TS.IFO)\n");
> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    if (c->opt_title > c->vmg_ifo->tt_srpt->nr_of_srpts) {
> +        av_log(s, AV_LOG_ERROR, "Title %d not found\n", c->opt_title);
> +
> +        return AVERROR_STREAM_NOT_FOUND;
> +    }
> +
> +    title_info = c->vmg_ifo->tt_srpt->title[c->opt_title - 1];
> +    if (c->opt_angle > title_info.nr_of_angles) {
> +        av_log(s, AV_LOG_ERROR, "Angle %d not found\n", c->opt_angle);
> +
> +        return AVERROR_STREAM_NOT_FOUND;
> +    }
> +
> +    if (title_info.nr_of_ptts < 1) {
> +        av_log(s, AV_LOG_ERROR, "Title %d has invalid headers (no parts)\n", c->opt_title);
> +
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    if (c->opt_chapter_start > title_info.nr_of_ptts
> +            || (c->opt_chapter_end > 0 && c->opt_chapter_end > title_info.nr_of_ptts)) {
> +        av_log(s, AV_LOG_ERROR, "Chapter (PTT) range [%d, %d] is invalid\n",
> +                                c->opt_chapter_start, c->opt_chapter_end);
> +
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    if (!(c->vts_ifo = ifoOpen(c->dvdread, title_info.title_set_nr))) {
> +        av_log(s, AV_LOG_ERROR, "Unable to process the VTS IFO structure\n");
> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    if (title_info.vts_ttn < 1
> +            || title_info.vts_ttn > 99
> +            || title_info.vts_ttn > c->vts_ifo->vts_ptt_srpt->nr_of_srpts
> +            || c->vts_ifo->vtsi_mat->nr_of_vts_audio_streams > 8
> +            || c->vts_ifo->vtsi_mat->nr_of_vts_subp_streams > 32) {
> +        av_log(s, AV_LOG_ERROR, "Title %d has invalid headers in VTS\n", c->opt_title);
> +
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    return 0;
> +}
> +
> +static void dvdvideo_play_close(AVFormatContext *s, DVDVideoPlaybackState *state)
> +{
> +    if (!state->dvdnav)
> +        return;
> +
> +    /* not allocated by av_malloc() */
> +    if (state->pgc_pg_times_est)
> +        free(state->pgc_pg_times_est);
> +
> +    if (dvdnav_close(state->dvdnav) < 0)
> +        av_log(s, AV_LOG_ERROR, "Unable to cleanly close dvdnav\n");
> +}
> +
> +static int dvdvideo_play_open(AVFormatContext *s, DVDVideoPlaybackState *state)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret = 0;
> +    dvdnav_logger_cb dvdnav_log_cb;
> +    dvdnav_status_t dvdnav_open_status;
> +    int cur_title, cur_pgcn, cur_pgn;
> +    pgc_t *pgc;
> +
> +    int32_t disc_region_mask;
> +    int32_t player_region_mask;
> +
> +    dvdnav_log_cb = (dvdnav_logger_cb) { .pf_log = dvdvideo_libdvdnav_log };
> +    dvdnav_open_status = dvdnav_open2(&state->dvdnav, s, &dvdnav_log_cb, s->url);
> +
> +    if (!state->dvdnav
> +            || dvdnav_open_status != DVDNAV_STATUS_OK
> +            || dvdnav_set_readahead_flag(state->dvdnav, 0) != DVDNAV_STATUS_OK
> +            || dvdnav_set_PGC_positioning_flag(state->dvdnav, 1) != DVDNAV_STATUS_OK
> +            || dvdnav_get_region_mask(state->dvdnav, &disc_region_mask) != DVDNAV_STATUS_OK) {
> +        av_log(s, AV_LOG_ERROR, "Unable to open the DVD for playback\n");
> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    player_region_mask = c->opt_region > 0 ? (1 << (c->opt_region - 1)) : disc_region_mask;
> +    if (dvdnav_set_region_mask(state->dvdnav, player_region_mask) != DVDNAV_STATUS_OK) {
> +        av_log(s, AV_LOG_ERROR, "Unable to set the playback region code %d\n", c->opt_region);
> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    if (c->opt_pgc > 0 && c->opt_pg > 0) {
> +        if (dvdnav_program_play(state->dvdnav, c->opt_title,
> +                                c->opt_pgc, c->opt_pg) != DVDNAV_STATUS_OK) {
> +            av_log(s, AV_LOG_ERROR, "Unable to start playback at title %d, PGC %d, PG %d\n",
> +                                    c->opt_title, c->opt_pgc, c->opt_pg);
> +
> +            return AVERROR_EXTERNAL;
> +        }
> +
> +        state->pgcn = c->opt_pgc;
> +        state->entry_pgn = c->opt_pg;
> +    } else {
> +        if (dvdnav_part_play(state->dvdnav, c->opt_title, c->opt_chapter_start) != DVDNAV_STATUS_OK
> +                || dvdnav_current_title_program(state->dvdnav, &cur_title,
> +                                                &cur_pgcn, &cur_pgn) != DVDNAV_STATUS_OK) {
> +            av_log(s, AV_LOG_ERROR, "Unable to start playback at title %d, chapter (PTT) %d\n",
> +                                    c->opt_title, c->opt_chapter_start);
> +
> +            return AVERROR_EXTERNAL;
> +        }
> +
> +        state->pgcn = cur_pgcn;
> +        state->entry_pgn = cur_pgn;
> +    }
> +
> +    pgc = c->vts_ifo->vts_pgcit->pgci_srp[state->pgcn - 1].pgc;
> +
> +    if (pgc->pg_playback_mode != 0) {
> +        av_log(s, AV_LOG_ERROR, "Non-sequential PGCs, such as shuffles, are not supported\n");
> +
> +        return AVERROR_PATCHWELCOME;
> +    }
> +
> +    if (dvdnav_angle_change(state->dvdnav, c->opt_angle) != DVDNAV_STATUS_OK) {
> +        av_log(s, AV_LOG_ERROR, "Unable to start playback at the given angle\n");
> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    /* dvdnav_describe_title_chapters() performs several safety checks on the title structure */
> +    /* take advantage of this side effect to ensure a safe navigation path */
> +    state->pgc_nb_pg_est = dvdnav_describe_title_chapters(state->dvdnav, c->opt_title,
> +                                                          &state->pgc_pg_times_est,
> +                                                          &state->pgc_duration_est);
> +    if (!state->pgc_nb_pg_est) {
> +        av_log(s, AV_LOG_ERROR, "Unable to validate title structure\n");
> +
> +        return AVERROR_EXTERNAL;
> +    }
> +
> +    state->nav_pts = dvdnav_get_current_time(state->dvdnav);
> +    state->vtsn = c->vmg_ifo->tt_srpt->title[c->opt_title - 1].title_set_nr;
> +
> +    state->pgc = pgc;
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_play_is_cell_promising(AVFormatContext *s, DVDVideoPlaybackState *state,
> +                                           int celln)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +    dvd_time_t cell_duration;
> +
> +    if (!c->opt_trim)
> +        return 1;
> +
> +    cell_duration = state->pgc->cell_playback[celln - 1].playback_time;
> +
> +    return cell_duration.second >= 1 || cell_duration.minute >= 1 || cell_duration.hour >= 1;
> +}
> +
> +static int dvdvideo_play_next_ps_block(AVFormatContext *s, DVDVideoPlaybackState *state,
> +                                       uint8_t *buf, int buf_size,
> +                                       int *p_nav_event,
> +                                       void (*flush_cb)(AVFormatContext *s))
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    uint8_t nav_buf[DVDVIDEO_BLOCK_SIZE] = {0};
> +    int nav_event;
> +    int nav_len;
> +
> +    dvdnav_vts_change_event_t *e_vts;
> +    dvdnav_cell_change_event_t *e_cell;
> +    int cur_title, cur_pgcn, cur_pgn, cur_angle, cur_title_unused, cur_ptt, cur_nb_angles;
> +    int is_cell_promising = 0;
> +    pci_t *e_pci;
> +    dsi_t *e_dsi;
> +
> +    if (buf_size != DVDVIDEO_BLOCK_SIZE) {
> +        av_log(s, AV_LOG_ERROR, "Invalid buffer size\n");
> +
> +        return AVERROR(ENOMEM);
> +    }
> +
> +    for (int i = 0; i < DVDVIDEO_MAX_PS_SEARCH_BLOCKS; i++) {
> +        if (ff_check_interrupt(&s->interrupt_callback))
> +            return AVERROR_EXIT;
> +
> +        if (dvdnav_get_next_block(state->dvdnav, nav_buf, &nav_event, &nav_len) != DVDNAV_STATUS_OK) {
> +            av_log(s, AV_LOG_ERROR, "Unable to read next block of PGC\n");
> +
> +            return AVERROR_INVALIDDATA;
> +        }
> +
> +        /* some discs follow NOPs with a premature stop event */
> +        if (nav_event == DVDNAV_STOP)
> +            return AVERROR_EOF;
> +
> +        if (nav_len > DVDVIDEO_BLOCK_SIZE) {
> +            av_log(s, AV_LOG_ERROR, "Invalid block size\n");
> +
> +            return AVERROR_INVALIDDATA;
> +        }
> +
> +        if (dvdnav_current_title_info(state->dvdnav, &cur_title,
> +                                      &cur_ptt) != DVDNAV_STATUS_OK) {
> +            av_log(s, AV_LOG_ERROR, "Unable to validate title coordinates\n");
> +
> +            return AVERROR_INVALIDDATA;
> +        }
> +
> +        /* we somehow navigated to a menu */
> +        if (cur_title == 0 || !dvdnav_is_domain_vts(state->dvdnav))
> +            return AVERROR_EOF;
> +
> +        if (dvdnav_current_title_program(state->dvdnav, &cur_title_unused,
> +                                         &cur_pgcn, &cur_pgn) != DVDNAV_STATUS_OK) {
> +            av_log(s, AV_LOG_ERROR, "Unable to validate PGC coordinates\n");
> +
> +            return AVERROR_INVALIDDATA;
> +        }
> +
> +        /* we somehow left the PGC */
> +        if (state->in_pgc && cur_pgcn != state->pgcn)
> +            return AVERROR_EOF;
> +
> +        if (dvdnav_get_angle_info(state->dvdnav, &cur_angle, &cur_nb_angles) != DVDNAV_STATUS_OK) {
> +            av_log(s, AV_LOG_ERROR, "Unable to validate angle coordinates\n");
> +
> +            return AVERROR_INVALIDDATA;
> +        }
> +
> +        av_log(s, nav_event == DVDNAV_BLOCK_OK ? AV_LOG_TRACE : AV_LOG_DEBUG,
> +                                "new block: i=%d nav_event=%d nav_len=%d cur_title=%d "
> +                                "cur_ptt=%d cur_angle=%d cur_celln=%d cur_pgcn=%d cur_pgn=%d "
> +                                "play_in_vts=%d play_in_pgc=%d play_in_ps=%d\n",
> +                                i, nav_event, nav_len, cur_title,
> +                                cur_ptt, cur_angle, state->celln, cur_pgcn, cur_pgn,
> +                                state->in_vts, state->in_pgc, state->in_ps);
> +
> +        switch (nav_event) {
> +            case DVDNAV_VTS_CHANGE:
> +                if (state->in_vts)
> +                    return AVERROR_EOF;
> +
> +                e_vts = (dvdnav_vts_change_event_t *) nav_buf;
> +
> +                if (e_vts->new_vtsN == state->vtsn && e_vts->new_domain == DVD_DOMAIN_VTSTitle)
> +                    state->in_vts = 1;
> +
> +                continue;
> +            case DVDNAV_CELL_CHANGE:
> +                if (!state->in_vts)
> +                    continue;
> +
> +                e_cell = (dvdnav_cell_change_event_t *) nav_buf;
> +                is_cell_promising = dvdvideo_play_is_cell_promising(s, state, e_cell->cellN);
> +
> +                av_log(s, AV_LOG_DEBUG, "new cell: prev=%d new=%d promising=%d\n",
> +                                        state->celln, e_cell->cellN, is_cell_promising);
> +
> +                if (!state->in_ps && !state->in_pgc) {
> +                    if (cur_title == c->opt_title && cur_ptt == c->opt_chapter_start
> +                            && cur_pgcn == state->pgcn && cur_pgn == state->entry_pgn
> +                            && is_cell_promising) {
> +                        state->in_pgc = 1;
> +                    }
> +
> +                    if (c->opt_trim && !is_cell_promising)
> +                        av_log(s, AV_LOG_INFO, "Skipping padding cell #%d\n", e_cell->cellN);
> +                } else if (state->celln >= e_cell->cellN || state->pgn > cur_pgn) {
> +                    return AVERROR_EOF;
> +                }
> +
> +                state->celln = e_cell->cellN;
> +                state->ptt = cur_ptt;
> +                state->pgn = cur_pgn;
> +
> +                continue;
> +            case DVDNAV_NAV_PACKET:
> +                if (!state->in_pgc)
> +                    continue;
> +
> +                if ((state->ptt > 0 && state->ptt > cur_ptt)
> +                        || (c->opt_chapter_end > 0 && cur_ptt > c->opt_chapter_end)) {
> +                    return AVERROR_EOF;
> +                }
> +
> +                e_pci = dvdnav_get_current_nav_pci(state->dvdnav);
> +                e_dsi = dvdnav_get_current_nav_dsi(state->dvdnav);
> +
> +                if (e_pci == NULL || e_dsi == NULL
> +                                  || e_pci->pci_gi.vobu_s_ptm > e_pci->pci_gi.vobu_e_ptm) {
> +                    av_log(s, AV_LOG_ERROR, "Invalid NAV packet\n");
> +
> +                    return AVERROR_INVALIDDATA;
> +                }
> +
> +                state->vobu_duration = e_pci->pci_gi.vobu_e_ptm - e_pci->pci_gi.vobu_s_ptm;
> +                state->pgc_elapsed += state->vobu_duration;
> +                state->nav_pts = dvdnav_get_current_time(state->dvdnav);
> +                state->ptt = cur_ptt;
> +                state->pgn = cur_pgn;
> +                state->nb_vobus_played++;
> +
> +                av_log(s, AV_LOG_DEBUG, "NAV pack: s_ptm=%d e_ptm=%d "
> +                                        "scr=%d lbn=%d vobu_duration=%d nav_pts=%ld\n",
> +                            e_pci->pci_gi.vobu_s_ptm, e_pci->pci_gi.vobu_e_ptm,
> +                            e_dsi->dsi_gi.nv_pck_scr,
> +                            e_pci->pci_gi.nv_pck_lbn, state->vobu_duration, state->nav_pts);
> +
> +                if (!state->in_ps) {
> +                    av_log(s, AV_LOG_DEBUG, "navigation: locked to program stream\n");
> +
> +                    state->in_ps = 1;
> +                } else {
> +                    if (state->vobu_e_ptm != e_pci->pci_gi.vobu_s_ptm) {
> +                        if (flush_cb)
> +                            flush_cb(s);
> +
> +                        state->ts_offset += state->vobu_e_ptm - e_pci->pci_gi.vobu_s_ptm;
> +                    }
> +                }
> +
> +                state->vobu_e_ptm = e_pci->pci_gi.vobu_e_ptm;
> +
> +                (*p_nav_event) = nav_event;
> +
> +                return nav_len;
> +            case DVDNAV_BLOCK_OK:
> +                if (!state->in_ps) {
> +                    if (state->in_pgc)
> +                        i = 0; /* necessary in case we are skipping junk cells at the beginning */
> +                    continue;
> +                }
> +
> +                if (nav_len != DVDVIDEO_BLOCK_SIZE) {
> +                    av_log(s, AV_LOG_ERROR, "Invalid block size\n");
> +
> +                    return AVERROR_INVALIDDATA;
> +                }
> +
> +                if (cur_angle != c->opt_angle) {
> +                    av_log(s, AV_LOG_ERROR, "Unexpected angle change\n");
> +
> +                    return AVERROR_INPUT_CHANGED;
> +                }
> +
> +                memcpy(buf, &nav_buf, nav_len);
> +
> +                /* in case NAV packet is missed */
> +                state->ptt = cur_ptt;
> +                state->pgn = cur_pgn;
> +
> +                (*p_nav_event) = nav_event;
> +
> +                return nav_len;
> +            case DVDNAV_STILL_FRAME:
> +            case DVDNAV_WAIT:
> +            case DVDNAV_HOP_CHANNEL:
> +            case DVDNAV_HIGHLIGHT:
> +                if (state->in_ps)
> +                    return AVERROR_EOF;
> +
> +                if (nav_event == DVDNAV_STILL_FRAME)
> +                    dvdnav_still_skip(state->dvdnav);
> +                if (nav_event == DVDNAV_WAIT)
> +                    dvdnav_wait_skip(state->dvdnav);
> +
> +                continue;
> +            case DVDNAV_STOP:
> +                return AVERROR_EOF;
> +            default:
> +                continue;
> +        }
> +    }
> +
> +    av_log(s, AV_LOG_ERROR, "Unable to find next program stream block\n");
> +
> +    return AVERROR_INVALIDDATA;
> +}
> +
> +static int dvdvideo_pgc_preindex(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret = 0, interrupt = 0;
> +    int nb_chapters = 0, last_ptt = c->opt_chapter_start;
> +    uint64_t cur_chapter_offset = 0, cur_chapter_duration = 0;
> +    DVDVideoPlaybackState *state;
> +
> +    uint8_t nav_buf[DVDVIDEO_BLOCK_SIZE];
> +    int nav_event;
> +
> +    if (c->opt_chapter_start == c->opt_chapter_end)
> +        return 0;
> +
> +    av_log(s, AV_LOG_INFO,
> +           "Indexing chapter markers, this will take a long time. Please wait...\n");
> +
> +    state = av_mallocz(sizeof(DVDVideoPlaybackState));

Should be put on the stack. Also: Missing check.

> +    if ((ret = dvdvideo_play_open(s, state)) < 0) {
> +        av_freep(&state);
> +        return ret;
> +    }
> +
> +    while (!(interrupt = ff_check_interrupt(&s->interrupt_callback))) {
> +        ret = dvdvideo_play_next_ps_block(s, state, nav_buf, DVDVIDEO_BLOCK_SIZE,
> +                                          &nav_event, NULL);
> +        if (ret < 0 && ret != AVERROR_EOF)
> +            goto end_free;
> +
> +        if (nav_event != DVDNAV_NAV_PACKET && ret != AVERROR_EOF)
> +            continue;
> +
> +        if (state->ptt == last_ptt) {
> +            cur_chapter_duration += state->vobu_duration;
> +            /* ensure we add the last chapter */
> +            if (ret != AVERROR_EOF)
> +                continue;
> +        }
> +
> +        if (!avpriv_new_chapter(s, nb_chapters, DVDVIDEO_TIME_BASE_Q, cur_chapter_offset,
> +                                cur_chapter_offset + cur_chapter_duration, NULL)) {
> +            av_log(s, AV_LOG_ERROR, "Unable to allocate chapter\n");
> +
> +            goto end_free;
> +        }
> +
> +        nb_chapters++;
> +        cur_chapter_offset += cur_chapter_duration;
> +        cur_chapter_duration = state->vobu_duration;
> +        last_ptt = state->ptt;
> +
> +        if (ret == AVERROR_EOF)
> +            break;
> +    }
> +
> +    if (interrupt) {
> +        ret = AVERROR_EXIT;
> +        goto end_free;
> +    }
> +
> +    if (ret < 0 && ret != AVERROR_EOF)
> +        goto end_free;
> +
> +    s->duration = av_rescale_q(state->pgc_elapsed, DVDVIDEO_TIME_BASE_Q, AV_TIME_BASE_Q);
> +    c->duration_ptm = state->pgc_elapsed;
> +
> +    av_log(s, AV_LOG_INFO, "Chapter marker indexing complete\n");
> +    ret = 0;
> +
> +end_free:
> +    dvdvideo_play_close(s, state);
> +    av_freep(&state);
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_pgc_chapters_setup(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    uint64_t time_prev = 0;
> +    int64_t total_duration = 0;
> +
> +    int chapter_start = c->opt_chapter_start - 1;
> +    int chapter_end = c->opt_chapter_end > 0 ? c->opt_chapter_end : c->play_state.pgc_nb_pg_est - 1;
> +
> +    if (chapter_start == chapter_end || c->play_state.pgc_nb_pg_est == 1) {
> +        s->duration = av_rescale_q(c->play_state.pgc_duration_est,
> +                                   DVDVIDEO_TIME_BASE_Q, AV_TIME_BASE_Q);
> +        return 0;
> +    }
> +
> +    for (int i = chapter_start; i < chapter_end; i++) {
> +        uint64_t time_effective = c->play_state.pgc_pg_times_est[i] - c->play_state.nav_pts;
> +
> +        if (!avpriv_new_chapter(s, i, DVDVIDEO_TIME_BASE_Q, time_prev,
> +                                time_effective, NULL)) {
> +            av_log(s, AV_LOG_ERROR, "Unable to allocate chapter\n");

Pointless log.

> +            return AVERROR(ENOMEM);
> +        }
> +
> +        time_prev = time_effective;
> +        total_duration = time_effective;
> +    }
> +
> +    if (c->opt_chapter_start == 1 && c->opt_chapter_end == 0)
> +        s->duration = av_rescale_q(c->play_state.pgc_duration_est,
> +                                   DVDVIDEO_TIME_BASE_Q, AV_TIME_BASE_Q);
> +    else
> +        s->duration = av_rescale_q(total_duration,
> +                                   DVDVIDEO_TIME_BASE_Q, AV_TIME_BASE_Q);
> +
> +    return 0;
> +}
> +
> +static int dvdvideo_video_stream_analyze(AVFormatContext *s, video_attr_t video_attr,
> +                                         DVDVideoVTSVideoStreamEntry *entry)
> +{
> +    AVRational framerate;
> +    int height = 0;
> +    int width = 0;
> +    int is_pal = video_attr.video_format == 1;
> +
> +    framerate = is_pal ? (AVRational) { 25, 1 } : (AVRational) { 30000, 1001 };
> +    height = is_pal ? 576 : 480;
> +
> +    if (height > 0) {
> +        switch (video_attr.picture_size) {
> +            case 0: /* D1 */
> +                width = 720;
> +                break;
> +            case 1: /* 4CIF */
> +                width = 704;
> +                break;
> +            case 2: /* Half D1 */
> +                width = 352;
> +                break;
> +            case 3: /* CIF */
> +                width = 352;
> +                height /= 2;
> +                break;
> +        }
> +    }
> +
> +    if (!width || !height) {
> +        av_log(s, AV_LOG_ERROR, "Invalid video dimensions\n");
> +
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    entry->startcode = 0x1E0;
> +    entry->codec_id = !video_attr.mpeg_version ? AV_CODEC_ID_MPEG1VIDEO : AV_CODEC_ID_MPEG2VIDEO;
> +    entry->width = width;
> +    entry->height = height;
> +    entry->dar = video_attr.display_aspect_ratio ? (AVRational) { 16, 9 } : (AVRational) { 4, 3 };
> +    entry->framerate = framerate;
> +    entry->has_cc = !is_pal && (video_attr.line21_cc_1 || video_attr.line21_cc_2);
> +
> +    return 0;
> +}
> +
> +static int dvdvideo_video_stream_add(AVFormatContext *s,
> +                                     DVDVideoVTSVideoStreamEntry *entry,
> +                                     enum AVStreamParseType need_parsing)
> +{
> +    AVStream *st;
> +    FFStream *sti;
> +
> +    st = avformat_new_stream(s, NULL);
> +    if (!st)
> +        return AVERROR(ENOMEM);
> +
> +    st->id = entry->startcode;
> +    st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
> +    st->codecpar->codec_id = entry->codec_id;
> +    st->codecpar->width = entry->width;
> +    st->codecpar->height = entry->height;
> +    st->codecpar->format = AV_PIX_FMT_YUV420P;
> +    st->codecpar->color_range = AVCOL_RANGE_MPEG;
> +
> +    st->codecpar->framerate = entry->framerate;
> +#if FF_API_R_FRAME_RATE
> +    st->r_frame_rate = entry->framerate;
> +#endif
> +    st->avg_frame_rate = entry->framerate;
> +
> +    sti = ffstream(st);
> +    sti->request_probe = 0;
> +    sti->need_parsing = need_parsing;
> +    sti->display_aspect_ratio = entry->dar;
> +    sti->avctx->framerate = entry->framerate;
> +
> +    if (entry->has_cc)
> +        sti->avctx->properties |= FF_CODEC_PROPERTY_CLOSED_CAPTIONS;
> +
> +    avpriv_set_pts_info(st, DVDVIDEO_PTS_WRAP_BITS,
> +                        DVDVIDEO_TIME_BASE_Q.num, DVDVIDEO_TIME_BASE_Q.den);
> +
> +    return 0;
> +}
> +
> +static int dvdvideo_video_stream_setup(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    DVDVideoVTSVideoStreamEntry *entry = NULL;
> +    int ret = 0;
> +
> +    entry = av_mallocz(sizeof(DVDVideoVTSVideoStreamEntry));

Should be put on the stack. Also: Missing check.

> +
> +    if ((ret = dvdvideo_video_stream_analyze(s, c->vts_ifo->vtsi_mat->vts_video_attr, entry)) < 0
> +            || (ret = dvdvideo_video_stream_add(c->mpeg_ctx, entry, AVSTREAM_PARSE_FULL)) < 0
> +            || (ret = dvdvideo_video_stream_add(s, entry, AVSTREAM_PARSE_HEADERS)) < 0) {
> +        av_freep(&entry);
> +        av_log(s, AV_LOG_ERROR, "Unable to allocate video stream\n");
> +
> +        return ret;
> +    }
> +
> +    av_freep(&entry);
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_audio_stream_analyze(AVFormatContext *s, audio_attr_t audio_attr,
> +                                         uint16_t audio_control, DVDVideoPGCAudioStreamEntry *entry)
> +{
> +    int startcode = 0;
> +    enum AVCodecID codec_id = AV_CODEC_ID_NONE;
> +    int sample_fmt = AV_SAMPLE_FMT_NONE;
> +    int sample_rate = 0;
> +    int bit_depth = 0;
> +    int nb_channels = 0;
> +    AVChannelLayout ch_layout = (AVChannelLayout) {0};
> +    char lang_dvd[3] = {0};
> +
> +    int position = (audio_control & 0x7F00) >> 8;
> +
> +    /* XXX(PATCHWELCOME): SDDS is not supported due to lack of sample material */
> +    switch (audio_attr.audio_format) {
> +        case 0: /* AC3 */
> +            codec_id = AV_CODEC_ID_AC3;
> +            sample_fmt = AV_SAMPLE_FMT_FLTP;
> +            sample_rate = 48000;
> +            startcode = 0x80 + position;
> +            break;
> +        case 2: /* MP1 */
> +            codec_id = AV_CODEC_ID_MP1;
> +            sample_fmt = audio_attr.quantization ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;
> +            sample_rate = 48000;
> +            bit_depth = audio_attr.quantization ? 20 : 16;
> +            startcode = 0x1C0 + position;
> +            break;
> +        case 3: /* MP2 */
> +            codec_id = AV_CODEC_ID_MP2;
> +            sample_fmt = audio_attr.quantization ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;
> +            sample_rate = 48000;
> +            bit_depth = audio_attr.quantization ? 20 : 16;
> +            startcode = 0x1C0 + position;
> +            break;
> +        case 4: /* DVD PCM */
> +            codec_id = AV_CODEC_ID_PCM_DVD;
> +            sample_fmt = audio_attr.quantization ? AV_SAMPLE_FMT_S32 : AV_SAMPLE_FMT_S16;
> +            sample_rate = audio_attr.sample_frequency ? 96000 : 48000;
> +            bit_depth = audio_attr.quantization == 2 ? 24 : (audio_attr.quantization ? 20 : 16);
> +            startcode = 0xA0 + position;
> +            break;
> +        case 6: /* DCA */
> +            codec_id = AV_CODEC_ID_DTS;
> +            sample_fmt = AV_SAMPLE_FMT_FLTP;
> +            sample_rate = 48000;
> +            bit_depth = audio_attr.quantization == 2 ? 24 : (audio_attr.quantization ? 20 : 16);
> +            startcode = 0x88 + position;
> +            break;
> +    }
> +
> +    nb_channels = audio_attr.channels + 1;
> +
> +    if (codec_id == AV_CODEC_ID_NONE
> +            || startcode == 0 || sample_fmt == AV_SAMPLE_FMT_NONE
> +            || sample_rate == 0 || nb_channels == 0) {
> +        av_log(s, AV_LOG_ERROR, "Invalid audio parameters\n");
> +
> +        return AVERROR_INVALIDDATA;
> +    }
> +
> +    if (nb_channels == 2)
> +        ch_layout = (AVChannelLayout) AV_CHANNEL_LAYOUT_STEREO;
> +    else if (nb_channels == 6)
> +        ch_layout = (AVChannelLayout) AV_CHANNEL_LAYOUT_5POINT1;
> +    else if (nb_channels == 7)
> +        ch_layout = (AVChannelLayout) AV_CHANNEL_LAYOUT_6POINT1;
> +    else if (nb_channels == 8)
> +        ch_layout = (AVChannelLayout) AV_CHANNEL_LAYOUT_7POINT1;
> +
> +    if (audio_attr.code_extension == 2)
> +        entry->disposition |= AV_DISPOSITION_VISUAL_IMPAIRED;
> +    if (audio_attr.code_extension == 3 || audio_attr.code_extension == 4)
> +        entry->disposition |= AV_DISPOSITION_COMMENT;
> +
> +    AV_WB16(lang_dvd, audio_attr.lang_code);
> +
> +    entry->startcode = startcode;
> +    entry->codec_id = codec_id;
> +    entry->sample_rate = sample_rate;
> +    entry->bit_depth = bit_depth;
> +    entry->nb_channels = nb_channels;
> +    entry->ch_layout = ch_layout;
> +    entry->lang_iso = (char *) ff_convert_lang_to(lang_dvd, AV_LANG_ISO639_2_BIBL);
> +
> +    return 0;
> +}
> +
> +static int dvdvideo_audio_stream_add(AVFormatContext *s, DVDVideoPGCAudioStreamEntry *entry,
> +                                     enum AVStreamParseType need_parsing)
> +{
> +    AVStream *st;
> +    FFStream *sti;
> +
> +    st = avformat_new_stream(s, NULL);
> +    if (!st)
> +        return AVERROR(ENOMEM);
> +
> +    st->id = entry->startcode;
> +    st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
> +    st->codecpar->codec_id = entry->codec_id;
> +    st->codecpar->format = entry->sample_fmt;
> +    st->codecpar->sample_rate = entry->sample_rate;
> +    st->codecpar->bits_per_coded_sample = entry->bit_depth;
> +    st->codecpar->bits_per_raw_sample = entry->bit_depth;
> +    st->codecpar->ch_layout = entry->ch_layout;
> +    st->codecpar->ch_layout.nb_channels = entry->nb_channels;
> +    st->disposition = entry->disposition;
> +
> +    if (entry->lang_iso)
> +        av_dict_set(&st->metadata, "language", entry->lang_iso, 0);
> +
> +    sti = ffstream(st);
> +    sti->request_probe = 0;
> +    sti->need_parsing = need_parsing;
> +
> +    avpriv_set_pts_info(st, DVDVIDEO_PTS_WRAP_BITS,
> +                        DVDVIDEO_TIME_BASE_Q.num, DVDVIDEO_TIME_BASE_Q.den);
> +
> +    return 0;
> +}
> +
> +static int dvdvideo_audio_stream_add_all(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret = 0;
> +
> +    for (int i = 0; i < c->vts_ifo->vtsi_mat->nr_of_vts_audio_streams; i++) {
> +        DVDVideoPGCAudioStreamEntry *entry = NULL;
> +
> +        if (!(c->play_state.pgc->audio_control[i] & 0x8000))
> +            continue;
> +
> +        entry = av_mallocz(sizeof(DVDVideoPGCAudioStreamEntry));

Should be put on the stack.

> +        if (!entry)
> +            return AVERROR(ENOMEM);
> +
> +        if ((ret = dvdvideo_audio_stream_analyze(s, c->vts_ifo->vtsi_mat->vts_audio_attr[i],
> +                c->play_state.pgc->audio_control[i], entry)) < 0)
> +            goto break_free_and_error;
> +
> +        if (c->vts_ifo->vtsi_mat->vts_audio_attr[i].application_mode == 1)
> +            av_log(s, AV_LOG_WARNING, "Karaoke metadata in stream %d will not be retained\n",
> +                                      entry->startcode);

Why not? We have AV_DISPOSITION_KARAOKE.

> +
> +        /* IFO structures can declare duplicate entries for the same startcode */
> +        for (int j = 0; j < s->nb_streams; j++)
> +            if (s->streams[j]->id == entry->startcode)
> +                goto continue_free;
> +
> +        if ((ret = dvdvideo_audio_stream_add(c->mpeg_ctx, entry, AVSTREAM_PARSE_FULL)) < 0
> +                || (ret = dvdvideo_audio_stream_add(s, entry, AVSTREAM_PARSE_HEADERS)) < 0)
> +            goto break_free_and_error;
> +
> +continue_free:
> +        av_freep(&entry);
> +        continue;
> +
> +break_free_and_error:
> +        av_freep(&entry);
> +        av_log(s, AV_LOG_ERROR, "Unable to allocate audio stream\n");
> +        return ret;
> +    }
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_subp_stream_analyze(AVFormatContext *s, uint32_t offset, subp_attr_t subp_attr,
> +                                        DVDVideoPGCSubtitleStreamEntry *entry)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    char lang_dvd[3] = {0};
> +
> +    entry->startcode = 0x20 + (offset & 0x1F);
> +
> +    if (subp_attr.lang_extension == 9)
> +        entry->disposition |= AV_DISPOSITION_FORCED;
> +
> +    AV_WB16(lang_dvd, subp_attr.lang_code);
> +    entry->lang_iso = (char *) ff_convert_lang_to(lang_dvd, AV_LANG_ISO639_2_BIBL);
> +
> +    return 0;
> +}
> +
> +static int dvdvideo_subp_stream_add(AVFormatContext *s, DVDVideoPGCSubtitleStreamEntry *entry,
> +                                    enum AVStreamParseType need_parsing)
> +{
> +    AVStream *st;
> +    FFStream *sti;
> +    int ret = 0;
> +
> +    st = avformat_new_stream(s, NULL);
> +    if (!st)
> +        return AVERROR(ENOMEM);
> +
> +    st->id = entry->startcode;
> +    st->codecpar->codec_type = AVMEDIA_TYPE_SUBTITLE;
> +    st->codecpar->codec_id = AV_CODEC_ID_DVD_SUBTITLE;
> +
> +    if (entry->lang_iso)
> +        av_dict_set(&st->metadata, "language", entry->lang_iso, 0);
> +
> +    av_dict_set(&st->metadata, "VIEWPORT", VIEWPORT_LABELS[entry->viewport], 0);
> +
> +    st->disposition = entry->disposition;
> +
> +    sti = ffstream(st);
> +    sti->request_probe = 0;
> +    sti->need_parsing = need_parsing;
> +
> +    avpriv_set_pts_info(st, DVDVIDEO_PTS_WRAP_BITS,
> +                        DVDVIDEO_TIME_BASE_Q.num, DVDVIDEO_TIME_BASE_Q.den);
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_subp_stream_add_internal(AVFormatContext *s, uint32_t offset,
> +                                             subp_attr_t subp_attr,
> +                                             enum DVDVideoSubpictureViewport viewport)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    DVDVideoPGCSubtitleStreamEntry *entry = NULL;
> +    int ret = 0;
> +
> +    entry = av_mallocz(sizeof(DVDVideoPGCSubtitleStreamEntry));

Unchecked allocation. Also use sizeof(*entry) to avoid typing.
But actually this need not be allocated at all, as this thing can just
be put on the stack.


> +    entry->viewport = viewport;
> +
> +    if ((ret = dvdvideo_subp_stream_analyze(s, offset, subp_attr, entry)) < 0)
> +        goto end_free_error;
> +
> +    /* IFO structures can declare duplicate entries for the same startcode */
> +    for (int i = 0; i < s->nb_streams; i++)
> +        if (s->streams[i]->id == entry->startcode)
> +            goto end_free;
> +
> +    if ((ret = dvdvideo_subp_stream_add(c->mpeg_ctx, entry, AVSTREAM_PARSE_FULL)) < 0

This makes this code add an AVStream to the child AVFormatContext. This
is not how it is supposed to be. You may not add AVStreams behind an
input AVFormatContext's back.

> +            || (ret = dvdvideo_subp_stream_add(s, entry, AVSTREAM_PARSE_HEADERS)) < 0)
> +        goto end_free_error;
> +
> +    goto end_free;
> +
> +end_free_error:
> +    av_log(s, AV_LOG_ERROR, "Unable to allocate subtitle stream\n");

No av_log for a some small allocations.

> +
> +end_free:
> +    av_freep(&entry);
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_subp_stream_add_all(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    if (!c->vts_ifo->vtsi_mat->nr_of_vts_subp_streams)
> +        return 0;
> +
> +    for (int i = 0; i < c->vts_ifo->vtsi_mat->nr_of_vts_subp_streams; i++) {
> +        int ret = 0;
> +        uint32_t subp_control;
> +        subp_attr_t subp_attr;
> +        video_attr_t video_attr;
> +
> +        subp_control = c->play_state.pgc->subp_control[i];
> +        if (!(subp_control & 0x80000000))
> +            continue;
> +
> +        /* there can be several presentations for one SPU */
> +        /* for now, be flexible with the DAR check due to weird authoring */
> +        video_attr = c->vts_ifo->vtsi_mat->vts_video_attr;
> +        subp_attr = c->vts_ifo->vtsi_mat->vts_subp_attr[i];
> +
> +        /* 4:3 */
> +        if (!video_attr.display_aspect_ratio) {
> +            if ((ret = dvdvideo_subp_stream_add_internal(s, subp_control >> 24, subp_attr,
> +                                                         DVDVIDEO_SUBP_VIEWPORT_FULLSCREEN)) < 0)
> +                return ret;
> +
> +            continue;
> +        }
> +
> +        /* 16:9 */
> +        if ((ret = dvdvideo_subp_stream_add_internal(s, subp_control >> 16, subp_attr,
> +                                                         DVDVIDEO_SUBP_VIEWPORT_WIDESCREEN)) < 0)
> +            return ret;
> +
> +        /* 16:9 letterbox */
> +        if (video_attr.permitted_df == 2 || video_attr.permitted_df == 0)
> +            if ((ret = dvdvideo_subp_stream_add_internal(s, subp_control >> 8, subp_attr,
> +                                                         DVDVIDEO_SUBP_VIEWPORT_LETTERBOX)) < 0)
> +                return ret;
> +
> +        /* 16:9 pan-and-scan */
> +        if (video_attr.permitted_df == 1 || video_attr.permitted_df == 0)
> +            if ((ret = dvdvideo_subp_stream_add_internal(s, subp_control, subp_attr,
> +                                                         DVDVIDEO_SUBP_VIEWPORT_PANSCAN)) < 0)
> +                return ret;
> +    }
> +
> +    return 0;
> +}
> +
> +static void dvdvideo_subdemux_flush(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    if (!c->play_seg_started)
> +        return;
> +
> +    av_log(s, AV_LOG_DEBUG, "flushing sub-demuxer\n");
> +    avio_flush(&c->mpeg_pb.pub);
> +    ff_read_frame_flush(c->mpeg_ctx);
> +    c->play_seg_started = 0;
> +}
> +
> +static int dvdvideo_subdemux_read_data(void *opaque, uint8_t *buf, int buf_size)
> +{
> +    AVFormatContext *s = opaque;
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret = 0;
> +    int nav_event;
> +
> +    if (c->play_end)
> +        return AVERROR_EOF;
> +
> +    ret = dvdvideo_play_next_ps_block(opaque, &c->play_state, buf, buf_size,
> +                                      &nav_event, dvdvideo_subdemux_flush);
> +
> +    if (ret == AVERROR_EOF) {
> +        c->mpeg_pb.pub.eof_reached = 1;
> +        c->play_end = 1;
> +
> +        return AVERROR_EOF;
> +    }
> +
> +    if (ret >= 0 && nav_event == DVDNAV_NAV_PACKET)
> +        return FFERROR_REDO;
> +
> +    return ret;
> +}
> +
> +static void dvdvideo_subdemux_close(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    av_freep(&c->mpeg_pb.pub.buffer);
> +    av_freep(&c->mpeg_pb);
> +    avformat_close_input(&c->mpeg_ctx);
> +}
> +
> +static int dvdvideo_subdemux_open(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret = 0;
> +
> +    if (!(c->mpeg_fmt = av_find_input_format("mpeg")))
> +        return AVERROR_DEMUXER_NOT_FOUND;
> +
> +    if (!(c->mpeg_ctx = avformat_alloc_context()))
> +        return AVERROR(ENOMEM);
> +
> +    if (!(c->mpeg_buf = av_mallocz(DVDVIDEO_BLOCK_SIZE))) {
> +        avformat_free_context(c->mpeg_ctx);
> +

This is dangerous: It frees the context, but leaves a dangling pointer
behind, which will cause a use-after-free in the read-close function
which is automatically called due to FF_FMT_INIT_CLEANUP.

> +        return AVERROR(ENOMEM);
> +    }
> +
> +    ffio_init_context(&c->mpeg_pb, c->mpeg_buf, DVDVIDEO_BLOCK_SIZE, 0, s,
> +                      dvdvideo_subdemux_read_data, NULL, NULL);
> +    c->mpeg_pb.pub.seekable = 0;
> +
> +    if ((ret = ff_copy_whiteblacklists(c->mpeg_ctx, s)) < 0) {
> +        avformat_free_context(c->mpeg_ctx);
> +
> +        return ret;
> +    }
> +
> +    c->mpeg_ctx->flags = AVFMT_FLAG_CUSTOM_IO | AVFMT_FLAG_GENPTS;
> +    c->mpeg_ctx->ctx_flags |= AVFMTCTX_UNSEEKABLE;
> +    c->mpeg_ctx->probesize = 0;
> +    c->mpeg_ctx->max_analyze_duration = 0;
> +    c->mpeg_ctx->interrupt_callback = s->interrupt_callback;
> +    c->mpeg_ctx->pb = &c->mpeg_pb.pub;
> +    c->mpeg_ctx->io_open = NULL;
> +
> +    if ((ret = avformat_open_input(&c->mpeg_ctx, "", c->mpeg_fmt, NULL)) < 0) {
> +        avformat_free_context(c->mpeg_ctx);

Unnecessary, as avformat_open_input() frees the context on error.

> +
> +        return ret;
> +    }
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_read_header(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret = 0;
> +
> +    if (c->opt_title == 0) {
> +        av_log(s, AV_LOG_INFO, "Defaulting to title #1. "
> +                               "This is not always the main feature, validation suggested.\n");
> +
> +        c->opt_title = 1;
> +    }
> +
> +    if (c->opt_pgc) {
> +        if (c->opt_pg == 0)
> +            av_log(s, AV_LOG_ERROR, "Invalid coordinates. If -pgc is set, -pg must be set too.\n");
> +        else if (c->opt_chapter_start > 1 || c->opt_chapter_end > 0 || c->opt_preindex)
> +            av_log(s, AV_LOG_ERROR, "-pgc is not compatible with the -preindex or "
> +                                    "-chapter_start/-chapter_end options\n");
> +
> +        return AVERROR(EINVAL);
> +    }
> +
> +    if ((ret = dvdvideo_ifo_open(s)) < 0)
> +        return ret;
> +
> +    if (c->opt_preindex && (ret = dvdvideo_pgc_preindex(s)) < 0)
> +        return ret;
> +
> +    if ((ret = dvdvideo_play_open(s, &c->play_state)) < 0
> +            || (ret = dvdvideo_subdemux_open(s)) < 0
> +            || (ret = dvdvideo_video_stream_setup(s)) < 0
> +            || (ret = dvdvideo_audio_stream_add_all(s)) < 0
> +            || (ret = dvdvideo_subp_stream_add_all(s)) < 0)
> +        return ret;
> +
> +    if (!c->opt_preindex)
> +        return dvdvideo_pgc_chapters_setup(s);
> +
> +    return ret;
> +}
> +
> +static int dvdvideo_read_packet(AVFormatContext *s, AVPacket *pkt)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    int ret;
> +    enum AVMediaType st_type;
> +    int64_t cur_delta = 0;
> +
> +    if (c->play_end)
> +        return AVERROR_EOF;
> +
> +    ret = av_read_frame(c->mpeg_ctx, pkt);
> +
> +    if (ret < 0)
> +        return ret;
> +
> +    if (!c->play_seg_started)
> +        c->play_seg_started = 1;
> +
> +    if (pkt->stream_index >= s->nb_streams) {
> +        av_log(s, AV_LOG_DEBUG, "discarding frame with unknown stream\n");
> +        goto skip_redo;
> +    }
> +
> +    st_type = c->mpeg_ctx->streams[pkt->stream_index]->codecpar->codec_type;
> +
> +    if (!c->play_started) {
> +        if (st_type != AVMEDIA_TYPE_VIDEO || pkt->pts == AV_NOPTS_VALUE
> +                                          || pkt->dts == AV_NOPTS_VALUE
> +                                          || !(pkt->flags & AV_PKT_FLAG_KEY)) {
> +            av_log(s, AV_LOG_DEBUG, "discarding non-video-keyframe at start\n");
> +            goto skip_redo;
> +        }
> +
> +        c->first_pts = pkt->pts;
> +        c->play_started = 1;
> +
> +        pkt->pts = 0;
> +        pkt->dts = c->play_state.ts_offset - pkt->pts;
> +    } else {
> +        cur_delta = c->play_state.ts_offset - c->first_pts;
> +
> +        if (c->play_state.nb_vobus_played == 1 && (pkt->pts == AV_NOPTS_VALUE
> +                                               ||  pkt->dts == AV_NOPTS_VALUE
> +                                               || (pkt->pts + cur_delta) < 0)) {
> +            av_log(s, AV_LOG_DEBUG, "discarding frame with negative or unset timestamp "
> +                                    "(this is OK at the start of the first playback VOBU)\n");
> +            goto skip_redo;
> +        }
> +
> +        if (pkt->pts != AV_NOPTS_VALUE)
> +            pkt->pts += cur_delta;
> +        if (pkt->dts != AV_NOPTS_VALUE)
> +            pkt->dts += cur_delta;
> +    }
> +
> +    av_log(s, AV_LOG_TRACE, "st=%d pts=%ld dts=%ld ts_offset=%ld first_pts=%ld\n",
> +                            pkt->stream_index, pkt->pts, pkt->dts,
> +                            c->play_state.ts_offset, c->first_pts);
> +    if (pkt->pts < 0)
> +        av_log(s, AV_LOG_WARNING, "Invalid frame PTS @ st=%d pts=%ld dts=%ld\n",
> +                                  pkt->stream_index, pkt->pts, pkt->dts);
> +
> +    return c->play_end ? AVERROR_EOF : 0;
> +
> +skip_redo:
> +    av_packet_unref(pkt);

Unnecessary, as the packet will be generically unreferenced if you
return an error code.

> +    return FFERROR_REDO;
> +}
> +
> +static int dvdvideo_close(AVFormatContext *s)
> +{
> +    DVDVideoDemuxContext *c = s->priv_data;
> +
> +    dvdvideo_subdemux_close(s);
> +    dvdvideo_play_close(s, &c->play_state);
> +    dvdvideo_ifo_close(s);
> +
> +    return 0;
> +}
> +
> +#define OFFSET(x) offsetof(DVDVideoDemuxContext, x)
> +static const AVOption dvdvideo_options[] = {
> +    {"angle",           "playback angle number",                                    OFFSET(opt_angle),          AV_OPT_TYPE_INT,    { .i64=1 },     1,          9,         AV_OPT_FLAG_DECODING_PARAM },
> +    {"chapter_end",     "exit chapter (PTT) number (0=end)",                        OFFSET(opt_chapter_end),    AV_OPT_TYPE_INT,    { .i64=0 },     0,          99,        AV_OPT_FLAG_DECODING_PARAM },
> +    {"chapter_start",   "entry chapter (PTT) number",                               OFFSET(opt_chapter_start),  AV_OPT_TYPE_INT,    { .i64=1 },     1,          99,        AV_OPT_FLAG_DECODING_PARAM },
> +    {"pg",              "entry PG number (0=auto)",                                 OFFSET(opt_pg),             AV_OPT_TYPE_INT,    { .i64=0 },     0,          255,       AV_OPT_FLAG_DECODING_PARAM },
> +    {"pgc",             "entry PGC number (0=auto)",                                OFFSET(opt_pgc),            AV_OPT_TYPE_INT,    { .i64=0 },     0,          999,       AV_OPT_FLAG_DECODING_PARAM },
> +    {"preindex",        "enable for accurate chapter markers, slow (2-pass read)",  OFFSET(opt_preindex),       AV_OPT_TYPE_BOOL,   { .i64=0 },     0,          1,         AV_OPT_FLAG_DECODING_PARAM },
> +    {"region",          "playback region number (0=free)",                          OFFSET(opt_region),         AV_OPT_TYPE_INT,    { .i64=0 },     0,          8,         AV_OPT_FLAG_DECODING_PARAM },
> +    {"title",           "title number (0=auto)",                                    OFFSET(opt_title),          AV_OPT_TYPE_INT,    { .i64=0 },     0,          99,        AV_OPT_FLAG_DECODING_PARAM },
> +    {"trim",            "trim padding cells from start",                            OFFSET(opt_trim),           AV_OPT_TYPE_BOOL,   { .i64=1 },     0,          1,         AV_OPT_FLAG_DECODING_PARAM },
> +    {NULL}
> +};
> +
> +static const AVClass dvdvideo_class = {
> +    .class_name = "DVD-Video demuxer",
> +    .item_name  = av_default_item_name,
> +    .option     = dvdvideo_options,
> +    .version    = LIBAVUTIL_VERSION_INT
> +};
> +
> +const AVInputFormat ff_dvdvideo_demuxer = {
> +    .name           = "dvdvideo",
> +    .long_name      = NULL_IF_CONFIG_SMALL("DVD-Video"),
> +    .priv_class     = &dvdvideo_class,
> +    .priv_data_size = sizeof(DVDVideoDemuxContext),
> +    .flags          = AVFMT_NOFILE | AVFMT_SHOW_IDS | AVFMT_TS_DISCONT | AVFMT_NO_BYTE_SEEK | AVFMT_NOGENSEARCH | AVFMT_NOBINSEARCH,
> +    .flags_internal = FF_FMT_INIT_CLEANUP,
> +    .read_close     = dvdvideo_close,
> +    .read_header    = dvdvideo_read_header,
> +    .read_packet    = dvdvideo_read_packet
> +};