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[FFmpeg-devel,4/5] avformat: add moflex demuxer

Message ID 20200901112946.3992-4-onemda@gmail.com
State Accepted
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Series [FFmpeg-devel,1/5] avcodec: add ADPCM IMA MOFLEX decoder
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Commit Message

Paul B Mahol Sept. 1, 2020, 11:29 a.m. UTC
Signed-off-by: Paul B Mahol <onemda@gmail.com>
---
 libavformat/Makefile     |   1 +
 libavformat/allformats.c |   1 +
 libavformat/moflex.c     | 360 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 362 insertions(+)
 create mode 100644 libavformat/moflex.c

Comments

Andreas Rheinhardt Sept. 3, 2020, 8:42 a.m. UTC | #1
Paul B Mahol:
> Signed-off-by: Paul B Mahol <onemda@gmail.com>
> ---
>  libavformat/Makefile     |   1 +
>  libavformat/allformats.c |   1 +
>  libavformat/moflex.c     | 360 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 362 insertions(+)
>  create mode 100644 libavformat/moflex.c
> 
> diff --git a/libavformat/Makefile b/libavformat/Makefile
> index cbb33fe37c..1e0ac317e5 100644
> --- a/libavformat/Makefile
> +++ b/libavformat/Makefile
> @@ -319,6 +319,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o riffdec.o
>  OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
>  OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
>  OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
> +OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
>  OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o replaygain.o
>  OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o vpcc.o \
>                                              movenchint.o mov_chan.o rtp.o \
> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
> index 0aa9dd7198..28331facb9 100644
> --- a/libavformat/allformats.c
> +++ b/libavformat/allformats.c
> @@ -249,6 +249,7 @@ extern AVInputFormat  ff_mlv_demuxer;
>  extern AVInputFormat  ff_mm_demuxer;
>  extern AVInputFormat  ff_mmf_demuxer;
>  extern AVOutputFormat ff_mmf_muxer;
> +extern AVInputFormat  ff_moflex_demuxer;
>  extern AVInputFormat  ff_mov_demuxer;
>  extern AVOutputFormat ff_mov_muxer;
>  extern AVOutputFormat ff_mp2_muxer;
> diff --git a/libavformat/moflex.c b/libavformat/moflex.c
> new file mode 100644
> index 0000000000..989623396f
> --- /dev/null
> +++ b/libavformat/moflex.c
> @@ -0,0 +1,360 @@
> +/*
> + * MOFLEX demuxer
> + * Copyright (c) 2020 Paul B Mahol
> + *
> + * 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
> + */
> +
> +#include "libavcodec/bytestream.h"
> +
> +#include "avformat.h"
> +#include "internal.h"
> +
> +typedef struct BitReader {
> +    unsigned last;
> +    unsigned pos;
> +} BitReader;
> +
> +typedef struct MOFLEXDemuxContext {
> +    unsigned size;
> +    int64_t pos;
> +    int64_t ts;
> +    int flags;
> +    int in_block;
> +
> +    BitReader br;
> +} MOFLEXDemuxContext;
> +
> +static int pop(BitReader *br, AVIOContext *pb)
> +{
> +    if (avio_feof(pb))
> +        return AVERROR_EOF;
> +
> +    if ((br->pos & 7) == 0)
> +        br->last = (unsigned)avio_r8(pb) << 24U;
> +    else
> +        br->last <<= 1;
> +
> +    br->pos++;
> +    return !!(br->last & 0x80000000);
> +}
> +
> +static int pop_int(BitReader *br, AVIOContext *pb, int n)
> +{
> +    int value = 0;
> +
> +    for (int i = 0; i < n; i++) {
> +        int ret = pop(br, pb);
> +
> +        if (ret < 0)
> +            return ret;
> +        value = 2 * value + ret;
> +    }
> +
> +    return value;
> +}
> +
> +static int pop_length(BitReader *br, AVIOContext *pb)
> +{
> +    int ret, n = 1;
> +
> +    while ((ret = pop(br, pb)) == 0)
> +        n++;
> +
> +    if (ret < 0)
> +        return ret;
> +    return n;
> +}
> +
> +static int read_var_byte(AVFormatContext *s, unsigned *out)
> +{
> +    AVIOContext *pb = s->pb;
> +    unsigned value = 0, data;
> +
> +    data = avio_r8(pb);
> +    if (!(data & 0x80)) {
> +        *out = data;
> +        return 0;
> +    }
> +
> +    value = (data & 0x7F) << 7;
> +    data = avio_r8(pb);
> +    if (!(data & 0x80)) {
> +        value |= data;
> +        *out = value;
> +        return 0;
> +    }
> +
> +    value = ((data & 0x7F) | value) << 7;
> +    data = avio_r8(pb);
> +    if (!(data & 0x80)) {
> +        value |= data;
> +        *out = value;
> +        return 0;
> +    }
> +
> +    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
> +    *out = value;
> +
> +    return 0;
> +}
> +
> +static int moflex_probe(const AVProbeData *p)
> +{
> +    GetByteContext gb;
> +    int score = 0;
> +
> +    bytestream2_init(&gb, p->buf, p->buf_size);
> +
> +    if (bytestream2_get_be16(&gb) != 0x4C32)
> +        return 0;
> +    score += 10;
> +
> +    bytestream2_skip(&gb, 10);
> +    if (bytestream2_get_be16(&gb) == 0)
> +        return 0;
> +    score += 5;
> +
> +    while (bytestream2_get_bytes_left(&gb) > 0) {
> +        int type = bytestream2_get_byte(&gb);
> +        int size = bytestream2_get_byte(&gb);
> +
> +        if (type == 0) {
> +            score += 5 * (size == 0);
> +            break;
> +        }
> +        if ((type == 1 && size == 12) ||
> +            (type == 2 && size ==  6) ||
> +            (type == 3 && size == 13) ||
> +            (type == 4 && size ==  2))
> +            score += 20;
> +        bytestream2_skip(&gb, size);
> +    }
> +
> +    return FFMIN(AVPROBE_SCORE_MAX, score);
> +}
> +
> +static int moflex_read_sync(AVFormatContext *s)
> +{
> +    MOFLEXDemuxContext *m = s->priv_data;
> +    AVIOContext *pb = s->pb;
> +
> +    if (avio_rb16(pb) != 0x4C32) {
> +        if (avio_feof(pb))
> +            return AVERROR_EOF;
> +        avio_seek(pb, -2, SEEK_CUR);
> +        return 1;
> +    }
> +
> +    avio_skip(pb, 2);
> +    m->ts = avio_rb64(pb);
> +    m->size = avio_rb16(pb) + 1;
> +
> +    while (!avio_feof(pb)) {
> +        unsigned type, ssize, codec_id = 0;
> +        unsigned codec_type, width = 0, height = 0, sample_rate = 0, channels = 0;
> +        int stream_index = -1;
> +        int format;
> +        AVRational fps;
> +
> +        read_var_byte(s, &type);
> +        read_var_byte(s, &ssize);
> +
> +        switch (type) {
> +        case 0:
> +            if (ssize > 0)
> +                avio_skip(pb, ssize);
> +            return 0;
> +        case 2:
> +            codec_type = AVMEDIA_TYPE_AUDIO;
> +            stream_index = avio_r8(pb);
> +            codec_id = avio_r8(pb);
> +            switch (codec_id) {
> +            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
> +            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
> +            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
> +            default:
> +                av_log(s, AV_LOG_ERROR, "Unsupported audio codec: %d\n", codec_id);
> +                return AVERROR_PATCHWELCOME;
> +            }
> +            sample_rate = avio_rb24(pb) + 1;
> +            channels = avio_r8(pb) + 1;
> +            break;
> +        case 1:
> +        case 3:
> +            codec_type = AVMEDIA_TYPE_VIDEO;
> +            stream_index = avio_r8(pb);
> +            codec_id = avio_r8(pb);
> +            switch (codec_id) {
> +            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
> +            default:
> +                av_log(s, AV_LOG_ERROR, "Unsupported video codec: %d\n", codec_id);
> +                return AVERROR_PATCHWELCOME;
> +            }
> +            fps.num = avio_rb16(pb);
> +            fps.den = avio_rb16(pb);
> +            width = avio_rb16(pb);
> +            height = avio_rb16(pb);
> +            format = AV_PIX_FMT_YUV420P;
> +            avio_skip(pb, type == 3 ? 3 : 2);
> +            break;
> +        case 4:
> +            codec_type = AVMEDIA_TYPE_DATA;
> +            stream_index = avio_r8(pb);
> +            avio_skip(pb, 1);
> +            break;
> +        }
> +
> +        if (stream_index == s->nb_streams) {
> +            AVStream *st = avformat_new_stream(s, NULL);
> +
> +            if (!st)
> +                return AVERROR(ENOMEM);
> +
> +            st->codecpar->codec_type = codec_type;
> +            st->codecpar->codec_id   = codec_id;
> +            st->codecpar->width      = width;
> +            st->codecpar->height     = height;
> +            st->codecpar->sample_rate= sample_rate;
> +            st->codecpar->channels   = channels;
> +            st->codecpar->format     = format;
> +            st->priv_data            = av_packet_alloc();
> +            if (!st->priv_data)
> +                return AVERROR(ENOMEM);

If this allocation fails when reading a packet, you end up with a stream
without priv_data. If the caller decides to call av_read_frame() again,
you can get a segfault, because the code for reading a packet presumes
every stream to have an AVPacket as priv_data.

> +
> +            if (sample_rate)
> +                avpriv_set_pts_info(st, 63, 1, sample_rate);
> +            else
> +                avpriv_set_pts_info(st, 63, fps.den, fps.num);
> +        }
> +    }
> +
> +    return 0;
> +}
> +
> +static int moflex_read_header(AVFormatContext *s)
> +{
> +    int ret;
> +
> +    ret = moflex_read_sync(s);
> +    if (ret < 0)
> +        return ret;
> +
> +    s->ctx_flags |= AVFMTCTX_NOHEADER;
> +    avio_seek(s->pb, 0, SEEK_SET);
> +
> +    return 0;
> +}
> +
> +static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
> +{
> +    MOFLEXDemuxContext *m = s->priv_data;
> +    AVIOContext *pb = s->pb;
> +    BitReader *br = &m->br;
> +    int ret;
> +
> +    while (!avio_feof(pb)) {
> +        if (!m->in_block) {
> +            m->pos = avio_tell(pb);
> +
> +            ret = moflex_read_sync(s);
> +            if (ret < 0)
> +                return ret;
> +
> +            m->flags = avio_r8(pb);
> +            if (m->flags & 2)
> +                avio_skip(pb, 2);
> +        }
> +
> +        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) && avio_r8(pb)) {
> +            int stream_index, bits, pkt_size, endframe;
> +            AVPacket *packet;
> +
> +            m->in_block = 1;
> +
> +            avio_seek(pb, -1, SEEK_CUR);
> +            br->pos = br->last = 0;
> +
> +            bits = pop_length(br, pb);
> +            if (bits < 0)
> +                return bits;
> +            stream_index = pop_int(br, pb, bits);
> +            if (stream_index < 0)
> +                return stream_index;
> +            if (stream_index >= s->nb_streams)
> +                return AVERROR_INVALIDDATA;
> +
> +            endframe = pop(br, pb);
> +            if (endframe < 0)
> +                return endframe;
> +            if (endframe) {
> +                bits = pop_length(br, pb);
> +                if (bits < 0)
> +                    return bits;
> +                pop_int(br, pb, bits);
> +                pop(br, pb);
> +                bits = pop_length(br, pb);
> +                if (bits < 0)
> +                    return bits;
> +                pop_int(br, pb, bits * 2 + 26);
> +            }
> +
> +            pkt_size = pop_int(br, pb, 13) + 1;
> +            packet   = s->streams[stream_index]->priv_data;
> +
> +            ret = av_append_packet(pb, packet, pkt_size);
> +            if (endframe) {
> +                av_packet_move_ref(pkt, packet);
> +                pkt->pos = m->pos;
> +                pkt->stream_index = stream_index;
> +                pkt->flags |= AV_PKT_FLAG_KEY;
> +                return ret;
> +            }
> +        }
> +
> +        m->in_block = 0;
> +
> +        if (m->flags % 2 == 0)
> +            avio_seek(pb, m->pos + m->size, SEEK_SET);
> +    }
> +
> +    return AVERROR_EOF;
> +}
> +
> +static int moflex_read_close(AVFormatContext *s)
> +{
> +    for (int i = 0; i < s->nb_streams; i++) {
> +        AVPacket *packet = s->streams[i]->priv_data;
> +
> +        av_packet_free(&packet);
> +        s->streams[i]->priv_data = 0;
> +    }
> +
> +    return 0;
> +}
> +
> +AVInputFormat ff_moflex_demuxer = {
> +    .name           = "moflex",
> +    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
> +    .priv_data_size = sizeof(MOFLEXDemuxContext),
> +    .read_probe     = moflex_probe,
> +    .read_header    = moflex_read_header,
> +    .read_packet    = moflex_read_packet,
> +    .read_close     = moflex_read_close,
> +    .extensions     = "moflex",
> +    .flags          = AVFMT_GENERIC_INDEX,
> +};
>
Paul B Mahol Sept. 3, 2020, 9 a.m. UTC | #2
On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
> Paul B Mahol:
>> Signed-off-by: Paul B Mahol <onemda@gmail.com>
>> ---
>>  libavformat/Makefile     |   1 +
>>  libavformat/allformats.c |   1 +
>>  libavformat/moflex.c     | 360 +++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 362 insertions(+)
>>  create mode 100644 libavformat/moflex.c
>>
>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>> index cbb33fe37c..1e0ac317e5 100644
>> --- a/libavformat/Makefile
>> +++ b/libavformat/Makefile
>> @@ -319,6 +319,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o
>> riffdec.o
>>  OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
>>  OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
>>  OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
>> +OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
>>  OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o
>> replaygain.o
>>  OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o
>> vpcc.o \
>>                                              movenchint.o mov_chan.o rtp.o
>> \
>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>> index 0aa9dd7198..28331facb9 100644
>> --- a/libavformat/allformats.c
>> +++ b/libavformat/allformats.c
>> @@ -249,6 +249,7 @@ extern AVInputFormat  ff_mlv_demuxer;
>>  extern AVInputFormat  ff_mm_demuxer;
>>  extern AVInputFormat  ff_mmf_demuxer;
>>  extern AVOutputFormat ff_mmf_muxer;
>> +extern AVInputFormat  ff_moflex_demuxer;
>>  extern AVInputFormat  ff_mov_demuxer;
>>  extern AVOutputFormat ff_mov_muxer;
>>  extern AVOutputFormat ff_mp2_muxer;
>> diff --git a/libavformat/moflex.c b/libavformat/moflex.c
>> new file mode 100644
>> index 0000000000..989623396f
>> --- /dev/null
>> +++ b/libavformat/moflex.c
>> @@ -0,0 +1,360 @@
>> +/*
>> + * MOFLEX demuxer
>> + * Copyright (c) 2020 Paul B Mahol
>> + *
>> + * 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
>> + */
>> +
>> +#include "libavcodec/bytestream.h"
>> +
>> +#include "avformat.h"
>> +#include "internal.h"
>> +
>> +typedef struct BitReader {
>> +    unsigned last;
>> +    unsigned pos;
>> +} BitReader;
>> +
>> +typedef struct MOFLEXDemuxContext {
>> +    unsigned size;
>> +    int64_t pos;
>> +    int64_t ts;
>> +    int flags;
>> +    int in_block;
>> +
>> +    BitReader br;
>> +} MOFLEXDemuxContext;
>> +
>> +static int pop(BitReader *br, AVIOContext *pb)
>> +{
>> +    if (avio_feof(pb))
>> +        return AVERROR_EOF;
>> +
>> +    if ((br->pos & 7) == 0)
>> +        br->last = (unsigned)avio_r8(pb) << 24U;
>> +    else
>> +        br->last <<= 1;
>> +
>> +    br->pos++;
>> +    return !!(br->last & 0x80000000);
>> +}
>> +
>> +static int pop_int(BitReader *br, AVIOContext *pb, int n)
>> +{
>> +    int value = 0;
>> +
>> +    for (int i = 0; i < n; i++) {
>> +        int ret = pop(br, pb);
>> +
>> +        if (ret < 0)
>> +            return ret;
>> +        value = 2 * value + ret;
>> +    }
>> +
>> +    return value;
>> +}
>> +
>> +static int pop_length(BitReader *br, AVIOContext *pb)
>> +{
>> +    int ret, n = 1;
>> +
>> +    while ((ret = pop(br, pb)) == 0)
>> +        n++;
>> +
>> +    if (ret < 0)
>> +        return ret;
>> +    return n;
>> +}
>> +
>> +static int read_var_byte(AVFormatContext *s, unsigned *out)
>> +{
>> +    AVIOContext *pb = s->pb;
>> +    unsigned value = 0, data;
>> +
>> +    data = avio_r8(pb);
>> +    if (!(data & 0x80)) {
>> +        *out = data;
>> +        return 0;
>> +    }
>> +
>> +    value = (data & 0x7F) << 7;
>> +    data = avio_r8(pb);
>> +    if (!(data & 0x80)) {
>> +        value |= data;
>> +        *out = value;
>> +        return 0;
>> +    }
>> +
>> +    value = ((data & 0x7F) | value) << 7;
>> +    data = avio_r8(pb);
>> +    if (!(data & 0x80)) {
>> +        value |= data;
>> +        *out = value;
>> +        return 0;
>> +    }
>> +
>> +    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
>> +    *out = value;
>> +
>> +    return 0;
>> +}
>> +
>> +static int moflex_probe(const AVProbeData *p)
>> +{
>> +    GetByteContext gb;
>> +    int score = 0;
>> +
>> +    bytestream2_init(&gb, p->buf, p->buf_size);
>> +
>> +    if (bytestream2_get_be16(&gb) != 0x4C32)
>> +        return 0;
>> +    score += 10;
>> +
>> +    bytestream2_skip(&gb, 10);
>> +    if (bytestream2_get_be16(&gb) == 0)
>> +        return 0;
>> +    score += 5;
>> +
>> +    while (bytestream2_get_bytes_left(&gb) > 0) {
>> +        int type = bytestream2_get_byte(&gb);
>> +        int size = bytestream2_get_byte(&gb);
>> +
>> +        if (type == 0) {
>> +            score += 5 * (size == 0);
>> +            break;
>> +        }
>> +        if ((type == 1 && size == 12) ||
>> +            (type == 2 && size ==  6) ||
>> +            (type == 3 && size == 13) ||
>> +            (type == 4 && size ==  2))
>> +            score += 20;
>> +        bytestream2_skip(&gb, size);
>> +    }
>> +
>> +    return FFMIN(AVPROBE_SCORE_MAX, score);
>> +}
>> +
>> +static int moflex_read_sync(AVFormatContext *s)
>> +{
>> +    MOFLEXDemuxContext *m = s->priv_data;
>> +    AVIOContext *pb = s->pb;
>> +
>> +    if (avio_rb16(pb) != 0x4C32) {
>> +        if (avio_feof(pb))
>> +            return AVERROR_EOF;
>> +        avio_seek(pb, -2, SEEK_CUR);
>> +        return 1;
>> +    }
>> +
>> +    avio_skip(pb, 2);
>> +    m->ts = avio_rb64(pb);
>> +    m->size = avio_rb16(pb) + 1;
>> +
>> +    while (!avio_feof(pb)) {
>> +        unsigned type, ssize, codec_id = 0;
>> +        unsigned codec_type, width = 0, height = 0, sample_rate = 0,
>> channels = 0;
>> +        int stream_index = -1;
>> +        int format;
>> +        AVRational fps;
>> +
>> +        read_var_byte(s, &type);
>> +        read_var_byte(s, &ssize);
>> +
>> +        switch (type) {
>> +        case 0:
>> +            if (ssize > 0)
>> +                avio_skip(pb, ssize);
>> +            return 0;
>> +        case 2:
>> +            codec_type = AVMEDIA_TYPE_AUDIO;
>> +            stream_index = avio_r8(pb);
>> +            codec_id = avio_r8(pb);
>> +            switch (codec_id) {
>> +            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
>> +            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
>> +            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
>> +            default:
>> +                av_log(s, AV_LOG_ERROR, "Unsupported audio codec: %d\n",
>> codec_id);
>> +                return AVERROR_PATCHWELCOME;
>> +            }
>> +            sample_rate = avio_rb24(pb) + 1;
>> +            channels = avio_r8(pb) + 1;
>> +            break;
>> +        case 1:
>> +        case 3:
>> +            codec_type = AVMEDIA_TYPE_VIDEO;
>> +            stream_index = avio_r8(pb);
>> +            codec_id = avio_r8(pb);
>> +            switch (codec_id) {
>> +            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
>> +            default:
>> +                av_log(s, AV_LOG_ERROR, "Unsupported video codec: %d\n",
>> codec_id);
>> +                return AVERROR_PATCHWELCOME;
>> +            }
>> +            fps.num = avio_rb16(pb);
>> +            fps.den = avio_rb16(pb);
>> +            width = avio_rb16(pb);
>> +            height = avio_rb16(pb);
>> +            format = AV_PIX_FMT_YUV420P;
>> +            avio_skip(pb, type == 3 ? 3 : 2);
>> +            break;
>> +        case 4:
>> +            codec_type = AVMEDIA_TYPE_DATA;
>> +            stream_index = avio_r8(pb);
>> +            avio_skip(pb, 1);
>> +            break;
>> +        }
>> +
>> +        if (stream_index == s->nb_streams) {
>> +            AVStream *st = avformat_new_stream(s, NULL);
>> +
>> +            if (!st)
>> +                return AVERROR(ENOMEM);
>> +
>> +            st->codecpar->codec_type = codec_type;
>> +            st->codecpar->codec_id   = codec_id;
>> +            st->codecpar->width      = width;
>> +            st->codecpar->height     = height;
>> +            st->codecpar->sample_rate= sample_rate;
>> +            st->codecpar->channels   = channels;
>> +            st->codecpar->format     = format;
>> +            st->priv_data            = av_packet_alloc();
>> +            if (!st->priv_data)
>> +                return AVERROR(ENOMEM);
>
> If this allocation fails when reading a packet, you end up with a stream
> without priv_data. If the caller decides to call av_read_frame() again,
> you can get a segfault, because the code for reading a packet presumes
> every stream to have an AVPacket as priv_data.

No this is huge libavformat bug. NULL pointer dereference when appending packet.

>
>> +
>> +            if (sample_rate)
>> +                avpriv_set_pts_info(st, 63, 1, sample_rate);
>> +            else
>> +                avpriv_set_pts_info(st, 63, fps.den, fps.num);
>> +        }
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int moflex_read_header(AVFormatContext *s)
>> +{
>> +    int ret;
>> +
>> +    ret = moflex_read_sync(s);
>> +    if (ret < 0)
>> +        return ret;
>> +
>> +    s->ctx_flags |= AVFMTCTX_NOHEADER;
>> +    avio_seek(s->pb, 0, SEEK_SET);
>> +
>> +    return 0;
>> +}
>> +
>> +static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
>> +{
>> +    MOFLEXDemuxContext *m = s->priv_data;
>> +    AVIOContext *pb = s->pb;
>> +    BitReader *br = &m->br;
>> +    int ret;
>> +
>> +    while (!avio_feof(pb)) {
>> +        if (!m->in_block) {
>> +            m->pos = avio_tell(pb);
>> +
>> +            ret = moflex_read_sync(s);
>> +            if (ret < 0)
>> +                return ret;
>> +
>> +            m->flags = avio_r8(pb);
>> +            if (m->flags & 2)
>> +                avio_skip(pb, 2);
>> +        }
>> +
>> +        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) &&
>> avio_r8(pb)) {
>> +            int stream_index, bits, pkt_size, endframe;
>> +            AVPacket *packet;
>> +
>> +            m->in_block = 1;
>> +
>> +            avio_seek(pb, -1, SEEK_CUR);
>> +            br->pos = br->last = 0;
>> +
>> +            bits = pop_length(br, pb);
>> +            if (bits < 0)
>> +                return bits;
>> +            stream_index = pop_int(br, pb, bits);
>> +            if (stream_index < 0)
>> +                return stream_index;
>> +            if (stream_index >= s->nb_streams)
>> +                return AVERROR_INVALIDDATA;
>> +
>> +            endframe = pop(br, pb);
>> +            if (endframe < 0)
>> +                return endframe;
>> +            if (endframe) {
>> +                bits = pop_length(br, pb);
>> +                if (bits < 0)
>> +                    return bits;
>> +                pop_int(br, pb, bits);
>> +                pop(br, pb);
>> +                bits = pop_length(br, pb);
>> +                if (bits < 0)
>> +                    return bits;
>> +                pop_int(br, pb, bits * 2 + 26);
>> +            }
>> +
>> +            pkt_size = pop_int(br, pb, 13) + 1;
>> +            packet   = s->streams[stream_index]->priv_data;
>> +
>> +            ret = av_append_packet(pb, packet, pkt_size);
>> +            if (endframe) {
>> +                av_packet_move_ref(pkt, packet);
>> +                pkt->pos = m->pos;
>> +                pkt->stream_index = stream_index;
>> +                pkt->flags |= AV_PKT_FLAG_KEY;
>> +                return ret;
>> +            }
>> +        }
>> +
>> +        m->in_block = 0;
>> +
>> +        if (m->flags % 2 == 0)
>> +            avio_seek(pb, m->pos + m->size, SEEK_SET);
>> +    }
>> +
>> +    return AVERROR_EOF;
>> +}
>> +
>> +static int moflex_read_close(AVFormatContext *s)
>> +{
>> +    for (int i = 0; i < s->nb_streams; i++) {
>> +        AVPacket *packet = s->streams[i]->priv_data;
>> +
>> +        av_packet_free(&packet);
>> +        s->streams[i]->priv_data = 0;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +AVInputFormat ff_moflex_demuxer = {
>> +    .name           = "moflex",
>> +    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
>> +    .priv_data_size = sizeof(MOFLEXDemuxContext),
>> +    .read_probe     = moflex_probe,
>> +    .read_header    = moflex_read_header,
>> +    .read_packet    = moflex_read_packet,
>> +    .read_close     = moflex_read_close,
>> +    .extensions     = "moflex",
>> +    .flags          = AVFMT_GENERIC_INDEX,
>> +};
>>
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Andreas Rheinhardt Sept. 3, 2020, 9:03 a.m. UTC | #3
Paul B Mahol:
> On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
>> Paul B Mahol:
>>> Signed-off-by: Paul B Mahol <onemda@gmail.com>
>>> ---
>>>  libavformat/Makefile     |   1 +
>>>  libavformat/allformats.c |   1 +
>>>  libavformat/moflex.c     | 360 +++++++++++++++++++++++++++++++++++++++
>>>  3 files changed, 362 insertions(+)
>>>  create mode 100644 libavformat/moflex.c
>>>
>>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>>> index cbb33fe37c..1e0ac317e5 100644
>>> --- a/libavformat/Makefile
>>> +++ b/libavformat/Makefile
>>> @@ -319,6 +319,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o
>>> riffdec.o
>>>  OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
>>>  OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
>>>  OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
>>> +OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
>>>  OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o
>>> replaygain.o
>>>  OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o
>>> vpcc.o \
>>>                                              movenchint.o mov_chan.o rtp.o
>>> \
>>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>>> index 0aa9dd7198..28331facb9 100644
>>> --- a/libavformat/allformats.c
>>> +++ b/libavformat/allformats.c
>>> @@ -249,6 +249,7 @@ extern AVInputFormat  ff_mlv_demuxer;
>>>  extern AVInputFormat  ff_mm_demuxer;
>>>  extern AVInputFormat  ff_mmf_demuxer;
>>>  extern AVOutputFormat ff_mmf_muxer;
>>> +extern AVInputFormat  ff_moflex_demuxer;
>>>  extern AVInputFormat  ff_mov_demuxer;
>>>  extern AVOutputFormat ff_mov_muxer;
>>>  extern AVOutputFormat ff_mp2_muxer;
>>> diff --git a/libavformat/moflex.c b/libavformat/moflex.c
>>> new file mode 100644
>>> index 0000000000..989623396f
>>> --- /dev/null
>>> +++ b/libavformat/moflex.c
>>> @@ -0,0 +1,360 @@
>>> +/*
>>> + * MOFLEX demuxer
>>> + * Copyright (c) 2020 Paul B Mahol
>>> + *
>>> + * 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
>>> + */
>>> +
>>> +#include "libavcodec/bytestream.h"
>>> +
>>> +#include "avformat.h"
>>> +#include "internal.h"
>>> +
>>> +typedef struct BitReader {
>>> +    unsigned last;
>>> +    unsigned pos;
>>> +} BitReader;
>>> +
>>> +typedef struct MOFLEXDemuxContext {
>>> +    unsigned size;
>>> +    int64_t pos;
>>> +    int64_t ts;
>>> +    int flags;
>>> +    int in_block;
>>> +
>>> +    BitReader br;
>>> +} MOFLEXDemuxContext;
>>> +
>>> +static int pop(BitReader *br, AVIOContext *pb)
>>> +{
>>> +    if (avio_feof(pb))
>>> +        return AVERROR_EOF;
>>> +
>>> +    if ((br->pos & 7) == 0)
>>> +        br->last = (unsigned)avio_r8(pb) << 24U;
>>> +    else
>>> +        br->last <<= 1;
>>> +
>>> +    br->pos++;
>>> +    return !!(br->last & 0x80000000);
>>> +}
>>> +
>>> +static int pop_int(BitReader *br, AVIOContext *pb, int n)
>>> +{
>>> +    int value = 0;
>>> +
>>> +    for (int i = 0; i < n; i++) {
>>> +        int ret = pop(br, pb);
>>> +
>>> +        if (ret < 0)
>>> +            return ret;
>>> +        value = 2 * value + ret;
>>> +    }
>>> +
>>> +    return value;
>>> +}
>>> +
>>> +static int pop_length(BitReader *br, AVIOContext *pb)
>>> +{
>>> +    int ret, n = 1;
>>> +
>>> +    while ((ret = pop(br, pb)) == 0)
>>> +        n++;
>>> +
>>> +    if (ret < 0)
>>> +        return ret;
>>> +    return n;
>>> +}
>>> +
>>> +static int read_var_byte(AVFormatContext *s, unsigned *out)
>>> +{
>>> +    AVIOContext *pb = s->pb;
>>> +    unsigned value = 0, data;
>>> +
>>> +    data = avio_r8(pb);
>>> +    if (!(data & 0x80)) {
>>> +        *out = data;
>>> +        return 0;
>>> +    }
>>> +
>>> +    value = (data & 0x7F) << 7;
>>> +    data = avio_r8(pb);
>>> +    if (!(data & 0x80)) {
>>> +        value |= data;
>>> +        *out = value;
>>> +        return 0;
>>> +    }
>>> +
>>> +    value = ((data & 0x7F) | value) << 7;
>>> +    data = avio_r8(pb);
>>> +    if (!(data & 0x80)) {
>>> +        value |= data;
>>> +        *out = value;
>>> +        return 0;
>>> +    }
>>> +
>>> +    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
>>> +    *out = value;
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int moflex_probe(const AVProbeData *p)
>>> +{
>>> +    GetByteContext gb;
>>> +    int score = 0;
>>> +
>>> +    bytestream2_init(&gb, p->buf, p->buf_size);
>>> +
>>> +    if (bytestream2_get_be16(&gb) != 0x4C32)
>>> +        return 0;
>>> +    score += 10;
>>> +
>>> +    bytestream2_skip(&gb, 10);
>>> +    if (bytestream2_get_be16(&gb) == 0)
>>> +        return 0;
>>> +    score += 5;
>>> +
>>> +    while (bytestream2_get_bytes_left(&gb) > 0) {
>>> +        int type = bytestream2_get_byte(&gb);
>>> +        int size = bytestream2_get_byte(&gb);
>>> +
>>> +        if (type == 0) {
>>> +            score += 5 * (size == 0);
>>> +            break;
>>> +        }
>>> +        if ((type == 1 && size == 12) ||
>>> +            (type == 2 && size ==  6) ||
>>> +            (type == 3 && size == 13) ||
>>> +            (type == 4 && size ==  2))
>>> +            score += 20;
>>> +        bytestream2_skip(&gb, size);
>>> +    }
>>> +
>>> +    return FFMIN(AVPROBE_SCORE_MAX, score);
>>> +}
>>> +
>>> +static int moflex_read_sync(AVFormatContext *s)
>>> +{
>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>> +    AVIOContext *pb = s->pb;
>>> +
>>> +    if (avio_rb16(pb) != 0x4C32) {
>>> +        if (avio_feof(pb))
>>> +            return AVERROR_EOF;
>>> +        avio_seek(pb, -2, SEEK_CUR);
>>> +        return 1;
>>> +    }
>>> +
>>> +    avio_skip(pb, 2);
>>> +    m->ts = avio_rb64(pb);
>>> +    m->size = avio_rb16(pb) + 1;
>>> +
>>> +    while (!avio_feof(pb)) {
>>> +        unsigned type, ssize, codec_id = 0;
>>> +        unsigned codec_type, width = 0, height = 0, sample_rate = 0,
>>> channels = 0;
>>> +        int stream_index = -1;
>>> +        int format;
>>> +        AVRational fps;
>>> +
>>> +        read_var_byte(s, &type);
>>> +        read_var_byte(s, &ssize);
>>> +
>>> +        switch (type) {
>>> +        case 0:
>>> +            if (ssize > 0)
>>> +                avio_skip(pb, ssize);
>>> +            return 0;
>>> +        case 2:
>>> +            codec_type = AVMEDIA_TYPE_AUDIO;
>>> +            stream_index = avio_r8(pb);
>>> +            codec_id = avio_r8(pb);
>>> +            switch (codec_id) {
>>> +            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
>>> +            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
>>> +            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
>>> +            default:
>>> +                av_log(s, AV_LOG_ERROR, "Unsupported audio codec: %d\n",
>>> codec_id);
>>> +                return AVERROR_PATCHWELCOME;
>>> +            }
>>> +            sample_rate = avio_rb24(pb) + 1;
>>> +            channels = avio_r8(pb) + 1;
>>> +            break;
>>> +        case 1:
>>> +        case 3:
>>> +            codec_type = AVMEDIA_TYPE_VIDEO;
>>> +            stream_index = avio_r8(pb);
>>> +            codec_id = avio_r8(pb);
>>> +            switch (codec_id) {
>>> +            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
>>> +            default:
>>> +                av_log(s, AV_LOG_ERROR, "Unsupported video codec: %d\n",
>>> codec_id);
>>> +                return AVERROR_PATCHWELCOME;
>>> +            }
>>> +            fps.num = avio_rb16(pb);
>>> +            fps.den = avio_rb16(pb);
>>> +            width = avio_rb16(pb);
>>> +            height = avio_rb16(pb);
>>> +            format = AV_PIX_FMT_YUV420P;
>>> +            avio_skip(pb, type == 3 ? 3 : 2);
>>> +            break;
>>> +        case 4:
>>> +            codec_type = AVMEDIA_TYPE_DATA;
>>> +            stream_index = avio_r8(pb);
>>> +            avio_skip(pb, 1);
>>> +            break;
>>> +        }
>>> +
>>> +        if (stream_index == s->nb_streams) {
>>> +            AVStream *st = avformat_new_stream(s, NULL);
>>> +
>>> +            if (!st)
>>> +                return AVERROR(ENOMEM);
>>> +
>>> +            st->codecpar->codec_type = codec_type;
>>> +            st->codecpar->codec_id   = codec_id;
>>> +            st->codecpar->width      = width;
>>> +            st->codecpar->height     = height;
>>> +            st->codecpar->sample_rate= sample_rate;
>>> +            st->codecpar->channels   = channels;
>>> +            st->codecpar->format     = format;
>>> +            st->priv_data            = av_packet_alloc();
>>> +            if (!st->priv_data)
>>> +                return AVERROR(ENOMEM);
>>
>> If this allocation fails when reading a packet, you end up with a stream
>> without priv_data. If the caller decides to call av_read_frame() again,
>> you can get a segfault, because the code for reading a packet presumes
>> every stream to have an AVPacket as priv_data.
> 
> No this is huge libavformat bug. NULL pointer dereference when appending packet.
> 

No it is a bug to call it with pkt == NULL.

>>
>>> +
>>> +            if (sample_rate)
>>> +                avpriv_set_pts_info(st, 63, 1, sample_rate);
>>> +            else
>>> +                avpriv_set_pts_info(st, 63, fps.den, fps.num);
>>> +        }
>>> +    }
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int moflex_read_header(AVFormatContext *s)
>>> +{
>>> +    int ret;
>>> +
>>> +    ret = moflex_read_sync(s);
>>> +    if (ret < 0)
>>> +        return ret;
>>> +
>>> +    s->ctx_flags |= AVFMTCTX_NOHEADER;
>>> +    avio_seek(s->pb, 0, SEEK_SET);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
>>> +{
>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>> +    AVIOContext *pb = s->pb;
>>> +    BitReader *br = &m->br;
>>> +    int ret;
>>> +
>>> +    while (!avio_feof(pb)) {
>>> +        if (!m->in_block) {
>>> +            m->pos = avio_tell(pb);
>>> +
>>> +            ret = moflex_read_sync(s);
>>> +            if (ret < 0)
>>> +                return ret;
>>> +
>>> +            m->flags = avio_r8(pb);
>>> +            if (m->flags & 2)
>>> +                avio_skip(pb, 2);
>>> +        }
>>> +
>>> +        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) &&
>>> avio_r8(pb)) {
>>> +            int stream_index, bits, pkt_size, endframe;
>>> +            AVPacket *packet;
>>> +
>>> +            m->in_block = 1;
>>> +
>>> +            avio_seek(pb, -1, SEEK_CUR);
>>> +            br->pos = br->last = 0;
>>> +
>>> +            bits = pop_length(br, pb);
>>> +            if (bits < 0)
>>> +                return bits;
>>> +            stream_index = pop_int(br, pb, bits);
>>> +            if (stream_index < 0)
>>> +                return stream_index;
>>> +            if (stream_index >= s->nb_streams)
>>> +                return AVERROR_INVALIDDATA;
>>> +
>>> +            endframe = pop(br, pb);
>>> +            if (endframe < 0)
>>> +                return endframe;
>>> +            if (endframe) {
>>> +                bits = pop_length(br, pb);
>>> +                if (bits < 0)
>>> +                    return bits;
>>> +                pop_int(br, pb, bits);
>>> +                pop(br, pb);
>>> +                bits = pop_length(br, pb);
>>> +                if (bits < 0)
>>> +                    return bits;
>>> +                pop_int(br, pb, bits * 2 + 26);
>>> +            }
>>> +
>>> +            pkt_size = pop_int(br, pb, 13) + 1;
>>> +            packet   = s->streams[stream_index]->priv_data;
>>> +
>>> +            ret = av_append_packet(pb, packet, pkt_size);
>>> +            if (endframe) {
>>> +                av_packet_move_ref(pkt, packet);
>>> +                pkt->pos = m->pos;
>>> +                pkt->stream_index = stream_index;
>>> +                pkt->flags |= AV_PKT_FLAG_KEY;
>>> +                return ret;
>>> +            }
>>> +        }
>>> +
>>> +        m->in_block = 0;
>>> +
>>> +        if (m->flags % 2 == 0)
>>> +            avio_seek(pb, m->pos + m->size, SEEK_SET);
>>> +    }
>>> +
>>> +    return AVERROR_EOF;
>>> +}
>>> +
>>> +static int moflex_read_close(AVFormatContext *s)
>>> +{
>>> +    for (int i = 0; i < s->nb_streams; i++) {
>>> +        AVPacket *packet = s->streams[i]->priv_data;
>>> +
>>> +        av_packet_free(&packet);
>>> +        s->streams[i]->priv_data = 0;
>>> +    }
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +AVInputFormat ff_moflex_demuxer = {
>>> +    .name           = "moflex",
>>> +    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
>>> +    .priv_data_size = sizeof(MOFLEXDemuxContext),
>>> +    .read_probe     = moflex_probe,
>>> +    .read_header    = moflex_read_header,
>>> +    .read_packet    = moflex_read_packet,
>>> +    .read_close     = moflex_read_close,
>>> +    .extensions     = "moflex",
>>> +    .flags          = AVFMT_GENERIC_INDEX,
>>> +};
>>>
>>
>> _______________________________________________
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>> ffmpeg-devel@ffmpeg.org
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
>> To unsubscribe, visit link above, or email
>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> 
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>
Paul B Mahol Sept. 3, 2020, 10:21 a.m. UTC | #4
On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
> Paul B Mahol:
>> On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
>>> Paul B Mahol:
>>>> Signed-off-by: Paul B Mahol <onemda@gmail.com>
>>>> ---
>>>>  libavformat/Makefile     |   1 +
>>>>  libavformat/allformats.c |   1 +
>>>>  libavformat/moflex.c     | 360 +++++++++++++++++++++++++++++++++++++++
>>>>  3 files changed, 362 insertions(+)
>>>>  create mode 100644 libavformat/moflex.c
>>>>
>>>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>>>> index cbb33fe37c..1e0ac317e5 100644
>>>> --- a/libavformat/Makefile
>>>> +++ b/libavformat/Makefile
>>>> @@ -319,6 +319,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o
>>>> riffdec.o
>>>>  OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
>>>>  OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
>>>>  OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
>>>> +OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
>>>>  OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o
>>>> replaygain.o
>>>>  OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o
>>>> vpcc.o \
>>>>                                              movenchint.o mov_chan.o
>>>> rtp.o
>>>> \
>>>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>>>> index 0aa9dd7198..28331facb9 100644
>>>> --- a/libavformat/allformats.c
>>>> +++ b/libavformat/allformats.c
>>>> @@ -249,6 +249,7 @@ extern AVInputFormat  ff_mlv_demuxer;
>>>>  extern AVInputFormat  ff_mm_demuxer;
>>>>  extern AVInputFormat  ff_mmf_demuxer;
>>>>  extern AVOutputFormat ff_mmf_muxer;
>>>> +extern AVInputFormat  ff_moflex_demuxer;
>>>>  extern AVInputFormat  ff_mov_demuxer;
>>>>  extern AVOutputFormat ff_mov_muxer;
>>>>  extern AVOutputFormat ff_mp2_muxer;
>>>> diff --git a/libavformat/moflex.c b/libavformat/moflex.c
>>>> new file mode 100644
>>>> index 0000000000..989623396f
>>>> --- /dev/null
>>>> +++ b/libavformat/moflex.c
>>>> @@ -0,0 +1,360 @@
>>>> +/*
>>>> + * MOFLEX demuxer
>>>> + * Copyright (c) 2020 Paul B Mahol
>>>> + *
>>>> + * 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
>>>> + */
>>>> +
>>>> +#include "libavcodec/bytestream.h"
>>>> +
>>>> +#include "avformat.h"
>>>> +#include "internal.h"
>>>> +
>>>> +typedef struct BitReader {
>>>> +    unsigned last;
>>>> +    unsigned pos;
>>>> +} BitReader;
>>>> +
>>>> +typedef struct MOFLEXDemuxContext {
>>>> +    unsigned size;
>>>> +    int64_t pos;
>>>> +    int64_t ts;
>>>> +    int flags;
>>>> +    int in_block;
>>>> +
>>>> +    BitReader br;
>>>> +} MOFLEXDemuxContext;
>>>> +
>>>> +static int pop(BitReader *br, AVIOContext *pb)
>>>> +{
>>>> +    if (avio_feof(pb))
>>>> +        return AVERROR_EOF;
>>>> +
>>>> +    if ((br->pos & 7) == 0)
>>>> +        br->last = (unsigned)avio_r8(pb) << 24U;
>>>> +    else
>>>> +        br->last <<= 1;
>>>> +
>>>> +    br->pos++;
>>>> +    return !!(br->last & 0x80000000);
>>>> +}
>>>> +
>>>> +static int pop_int(BitReader *br, AVIOContext *pb, int n)
>>>> +{
>>>> +    int value = 0;
>>>> +
>>>> +    for (int i = 0; i < n; i++) {
>>>> +        int ret = pop(br, pb);
>>>> +
>>>> +        if (ret < 0)
>>>> +            return ret;
>>>> +        value = 2 * value + ret;
>>>> +    }
>>>> +
>>>> +    return value;
>>>> +}
>>>> +
>>>> +static int pop_length(BitReader *br, AVIOContext *pb)
>>>> +{
>>>> +    int ret, n = 1;
>>>> +
>>>> +    while ((ret = pop(br, pb)) == 0)
>>>> +        n++;
>>>> +
>>>> +    if (ret < 0)
>>>> +        return ret;
>>>> +    return n;
>>>> +}
>>>> +
>>>> +static int read_var_byte(AVFormatContext *s, unsigned *out)
>>>> +{
>>>> +    AVIOContext *pb = s->pb;
>>>> +    unsigned value = 0, data;
>>>> +
>>>> +    data = avio_r8(pb);
>>>> +    if (!(data & 0x80)) {
>>>> +        *out = data;
>>>> +        return 0;
>>>> +    }
>>>> +
>>>> +    value = (data & 0x7F) << 7;
>>>> +    data = avio_r8(pb);
>>>> +    if (!(data & 0x80)) {
>>>> +        value |= data;
>>>> +        *out = value;
>>>> +        return 0;
>>>> +    }
>>>> +
>>>> +    value = ((data & 0x7F) | value) << 7;
>>>> +    data = avio_r8(pb);
>>>> +    if (!(data & 0x80)) {
>>>> +        value |= data;
>>>> +        *out = value;
>>>> +        return 0;
>>>> +    }
>>>> +
>>>> +    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
>>>> +    *out = value;
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int moflex_probe(const AVProbeData *p)
>>>> +{
>>>> +    GetByteContext gb;
>>>> +    int score = 0;
>>>> +
>>>> +    bytestream2_init(&gb, p->buf, p->buf_size);
>>>> +
>>>> +    if (bytestream2_get_be16(&gb) != 0x4C32)
>>>> +        return 0;
>>>> +    score += 10;
>>>> +
>>>> +    bytestream2_skip(&gb, 10);
>>>> +    if (bytestream2_get_be16(&gb) == 0)
>>>> +        return 0;
>>>> +    score += 5;
>>>> +
>>>> +    while (bytestream2_get_bytes_left(&gb) > 0) {
>>>> +        int type = bytestream2_get_byte(&gb);
>>>> +        int size = bytestream2_get_byte(&gb);
>>>> +
>>>> +        if (type == 0) {
>>>> +            score += 5 * (size == 0);
>>>> +            break;
>>>> +        }
>>>> +        if ((type == 1 && size == 12) ||
>>>> +            (type == 2 && size ==  6) ||
>>>> +            (type == 3 && size == 13) ||
>>>> +            (type == 4 && size ==  2))
>>>> +            score += 20;
>>>> +        bytestream2_skip(&gb, size);
>>>> +    }
>>>> +
>>>> +    return FFMIN(AVPROBE_SCORE_MAX, score);
>>>> +}
>>>> +
>>>> +static int moflex_read_sync(AVFormatContext *s)
>>>> +{
>>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>>> +    AVIOContext *pb = s->pb;
>>>> +
>>>> +    if (avio_rb16(pb) != 0x4C32) {
>>>> +        if (avio_feof(pb))
>>>> +            return AVERROR_EOF;
>>>> +        avio_seek(pb, -2, SEEK_CUR);
>>>> +        return 1;
>>>> +    }
>>>> +
>>>> +    avio_skip(pb, 2);
>>>> +    m->ts = avio_rb64(pb);
>>>> +    m->size = avio_rb16(pb) + 1;
>>>> +
>>>> +    while (!avio_feof(pb)) {
>>>> +        unsigned type, ssize, codec_id = 0;
>>>> +        unsigned codec_type, width = 0, height = 0, sample_rate = 0,
>>>> channels = 0;
>>>> +        int stream_index = -1;
>>>> +        int format;
>>>> +        AVRational fps;
>>>> +
>>>> +        read_var_byte(s, &type);
>>>> +        read_var_byte(s, &ssize);
>>>> +
>>>> +        switch (type) {
>>>> +        case 0:
>>>> +            if (ssize > 0)
>>>> +                avio_skip(pb, ssize);
>>>> +            return 0;
>>>> +        case 2:
>>>> +            codec_type = AVMEDIA_TYPE_AUDIO;
>>>> +            stream_index = avio_r8(pb);
>>>> +            codec_id = avio_r8(pb);
>>>> +            switch (codec_id) {
>>>> +            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
>>>> +            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
>>>> +            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
>>>> +            default:
>>>> +                av_log(s, AV_LOG_ERROR, "Unsupported audio codec:
>>>> %d\n",
>>>> codec_id);
>>>> +                return AVERROR_PATCHWELCOME;
>>>> +            }
>>>> +            sample_rate = avio_rb24(pb) + 1;
>>>> +            channels = avio_r8(pb) + 1;
>>>> +            break;
>>>> +        case 1:
>>>> +        case 3:
>>>> +            codec_type = AVMEDIA_TYPE_VIDEO;
>>>> +            stream_index = avio_r8(pb);
>>>> +            codec_id = avio_r8(pb);
>>>> +            switch (codec_id) {
>>>> +            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
>>>> +            default:
>>>> +                av_log(s, AV_LOG_ERROR, "Unsupported video codec:
>>>> %d\n",
>>>> codec_id);
>>>> +                return AVERROR_PATCHWELCOME;
>>>> +            }
>>>> +            fps.num = avio_rb16(pb);
>>>> +            fps.den = avio_rb16(pb);
>>>> +            width = avio_rb16(pb);
>>>> +            height = avio_rb16(pb);
>>>> +            format = AV_PIX_FMT_YUV420P;
>>>> +            avio_skip(pb, type == 3 ? 3 : 2);
>>>> +            break;
>>>> +        case 4:
>>>> +            codec_type = AVMEDIA_TYPE_DATA;
>>>> +            stream_index = avio_r8(pb);
>>>> +            avio_skip(pb, 1);
>>>> +            break;
>>>> +        }
>>>> +
>>>> +        if (stream_index == s->nb_streams) {
>>>> +            AVStream *st = avformat_new_stream(s, NULL);
>>>> +
>>>> +            if (!st)
>>>> +                return AVERROR(ENOMEM);
>>>> +
>>>> +            st->codecpar->codec_type = codec_type;
>>>> +            st->codecpar->codec_id   = codec_id;
>>>> +            st->codecpar->width      = width;
>>>> +            st->codecpar->height     = height;
>>>> +            st->codecpar->sample_rate= sample_rate;
>>>> +            st->codecpar->channels   = channels;
>>>> +            st->codecpar->format     = format;
>>>> +            st->priv_data            = av_packet_alloc();
>>>> +            if (!st->priv_data)
>>>> +                return AVERROR(ENOMEM);
>>>
>>> If this allocation fails when reading a packet, you end up with a stream
>>> without priv_data. If the caller decides to call av_read_frame() again,
>>> you can get a segfault, because the code for reading a packet presumes
>>> every stream to have an AVPacket as priv_data.
>>
>> No this is huge libavformat bug. NULL pointer dereference when appending
>> packet.
>>
>
> No it is a bug to call it with pkt == NULL.

Nope my code is correct.

av_append_packet is buggy.

>
>>>
>>>> +
>>>> +            if (sample_rate)
>>>> +                avpriv_set_pts_info(st, 63, 1, sample_rate);
>>>> +            else
>>>> +                avpriv_set_pts_info(st, 63, fps.den, fps.num);
>>>> +        }
>>>> +    }
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int moflex_read_header(AVFormatContext *s)
>>>> +{
>>>> +    int ret;
>>>> +
>>>> +    ret = moflex_read_sync(s);
>>>> +    if (ret < 0)
>>>> +        return ret;
>>>> +
>>>> +    s->ctx_flags |= AVFMTCTX_NOHEADER;
>>>> +    avio_seek(s->pb, 0, SEEK_SET);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
>>>> +{
>>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>>> +    AVIOContext *pb = s->pb;
>>>> +    BitReader *br = &m->br;
>>>> +    int ret;
>>>> +
>>>> +    while (!avio_feof(pb)) {
>>>> +        if (!m->in_block) {
>>>> +            m->pos = avio_tell(pb);
>>>> +
>>>> +            ret = moflex_read_sync(s);
>>>> +            if (ret < 0)
>>>> +                return ret;
>>>> +
>>>> +            m->flags = avio_r8(pb);
>>>> +            if (m->flags & 2)
>>>> +                avio_skip(pb, 2);
>>>> +        }
>>>> +
>>>> +        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) &&
>>>> avio_r8(pb)) {
>>>> +            int stream_index, bits, pkt_size, endframe;
>>>> +            AVPacket *packet;
>>>> +
>>>> +            m->in_block = 1;
>>>> +
>>>> +            avio_seek(pb, -1, SEEK_CUR);
>>>> +            br->pos = br->last = 0;
>>>> +
>>>> +            bits = pop_length(br, pb);
>>>> +            if (bits < 0)
>>>> +                return bits;
>>>> +            stream_index = pop_int(br, pb, bits);
>>>> +            if (stream_index < 0)
>>>> +                return stream_index;
>>>> +            if (stream_index >= s->nb_streams)
>>>> +                return AVERROR_INVALIDDATA;
>>>> +
>>>> +            endframe = pop(br, pb);
>>>> +            if (endframe < 0)
>>>> +                return endframe;
>>>> +            if (endframe) {
>>>> +                bits = pop_length(br, pb);
>>>> +                if (bits < 0)
>>>> +                    return bits;
>>>> +                pop_int(br, pb, bits);
>>>> +                pop(br, pb);
>>>> +                bits = pop_length(br, pb);
>>>> +                if (bits < 0)
>>>> +                    return bits;
>>>> +                pop_int(br, pb, bits * 2 + 26);
>>>> +            }
>>>> +
>>>> +            pkt_size = pop_int(br, pb, 13) + 1;
>>>> +            packet   = s->streams[stream_index]->priv_data;
>>>> +
>>>> +            ret = av_append_packet(pb, packet, pkt_size);
>>>> +            if (endframe) {
>>>> +                av_packet_move_ref(pkt, packet);
>>>> +                pkt->pos = m->pos;
>>>> +                pkt->stream_index = stream_index;
>>>> +                pkt->flags |= AV_PKT_FLAG_KEY;
>>>> +                return ret;
>>>> +            }
>>>> +        }
>>>> +
>>>> +        m->in_block = 0;
>>>> +
>>>> +        if (m->flags % 2 == 0)
>>>> +            avio_seek(pb, m->pos + m->size, SEEK_SET);
>>>> +    }
>>>> +
>>>> +    return AVERROR_EOF;
>>>> +}
>>>> +
>>>> +static int moflex_read_close(AVFormatContext *s)
>>>> +{
>>>> +    for (int i = 0; i < s->nb_streams; i++) {
>>>> +        AVPacket *packet = s->streams[i]->priv_data;
>>>> +
>>>> +        av_packet_free(&packet);
>>>> +        s->streams[i]->priv_data = 0;
>>>> +    }
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +AVInputFormat ff_moflex_demuxer = {
>>>> +    .name           = "moflex",
>>>> +    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
>>>> +    .priv_data_size = sizeof(MOFLEXDemuxContext),
>>>> +    .read_probe     = moflex_probe,
>>>> +    .read_header    = moflex_read_header,
>>>> +    .read_packet    = moflex_read_packet,
>>>> +    .read_close     = moflex_read_close,
>>>> +    .extensions     = "moflex",
>>>> +    .flags          = AVFMT_GENERIC_INDEX,
>>>> +};
>>>>
>>>
>>> _______________________________________________
>>> ffmpeg-devel mailing list
>>> ffmpeg-devel@ffmpeg.org
>>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>>
>>> To unsubscribe, visit link above, or email
>>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>> _______________________________________________
>> ffmpeg-devel mailing list
>> ffmpeg-devel@ffmpeg.org
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
>> To unsubscribe, visit link above, or email
>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>>
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Andreas Rheinhardt Sept. 3, 2020, 10:27 a.m. UTC | #5
Paul B Mahol:
> On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
>> Paul B Mahol:
>>> On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
>>>> Paul B Mahol:
>>>>> Signed-off-by: Paul B Mahol <onemda@gmail.com>
>>>>> ---
>>>>>  libavformat/Makefile     |   1 +
>>>>>  libavformat/allformats.c |   1 +
>>>>>  libavformat/moflex.c     | 360 +++++++++++++++++++++++++++++++++++++++
>>>>>  3 files changed, 362 insertions(+)
>>>>>  create mode 100644 libavformat/moflex.c
>>>>>
>>>>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>>>>> index cbb33fe37c..1e0ac317e5 100644
>>>>> --- a/libavformat/Makefile
>>>>> +++ b/libavformat/Makefile
>>>>> @@ -319,6 +319,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o
>>>>> riffdec.o
>>>>>  OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
>>>>>  OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
>>>>>  OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
>>>>> +OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
>>>>>  OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o
>>>>> replaygain.o
>>>>>  OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o
>>>>> vpcc.o \
>>>>>                                              movenchint.o mov_chan.o
>>>>> rtp.o
>>>>> \
>>>>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>>>>> index 0aa9dd7198..28331facb9 100644
>>>>> --- a/libavformat/allformats.c
>>>>> +++ b/libavformat/allformats.c
>>>>> @@ -249,6 +249,7 @@ extern AVInputFormat  ff_mlv_demuxer;
>>>>>  extern AVInputFormat  ff_mm_demuxer;
>>>>>  extern AVInputFormat  ff_mmf_demuxer;
>>>>>  extern AVOutputFormat ff_mmf_muxer;
>>>>> +extern AVInputFormat  ff_moflex_demuxer;
>>>>>  extern AVInputFormat  ff_mov_demuxer;
>>>>>  extern AVOutputFormat ff_mov_muxer;
>>>>>  extern AVOutputFormat ff_mp2_muxer;
>>>>> diff --git a/libavformat/moflex.c b/libavformat/moflex.c
>>>>> new file mode 100644
>>>>> index 0000000000..989623396f
>>>>> --- /dev/null
>>>>> +++ b/libavformat/moflex.c
>>>>> @@ -0,0 +1,360 @@
>>>>> +/*
>>>>> + * MOFLEX demuxer
>>>>> + * Copyright (c) 2020 Paul B Mahol
>>>>> + *
>>>>> + * 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
>>>>> + */
>>>>> +
>>>>> +#include "libavcodec/bytestream.h"
>>>>> +
>>>>> +#include "avformat.h"
>>>>> +#include "internal.h"
>>>>> +
>>>>> +typedef struct BitReader {
>>>>> +    unsigned last;
>>>>> +    unsigned pos;
>>>>> +} BitReader;
>>>>> +
>>>>> +typedef struct MOFLEXDemuxContext {
>>>>> +    unsigned size;
>>>>> +    int64_t pos;
>>>>> +    int64_t ts;
>>>>> +    int flags;
>>>>> +    int in_block;
>>>>> +
>>>>> +    BitReader br;
>>>>> +} MOFLEXDemuxContext;
>>>>> +
>>>>> +static int pop(BitReader *br, AVIOContext *pb)
>>>>> +{
>>>>> +    if (avio_feof(pb))
>>>>> +        return AVERROR_EOF;
>>>>> +
>>>>> +    if ((br->pos & 7) == 0)
>>>>> +        br->last = (unsigned)avio_r8(pb) << 24U;
>>>>> +    else
>>>>> +        br->last <<= 1;
>>>>> +
>>>>> +    br->pos++;
>>>>> +    return !!(br->last & 0x80000000);
>>>>> +}
>>>>> +
>>>>> +static int pop_int(BitReader *br, AVIOContext *pb, int n)
>>>>> +{
>>>>> +    int value = 0;
>>>>> +
>>>>> +    for (int i = 0; i < n; i++) {
>>>>> +        int ret = pop(br, pb);
>>>>> +
>>>>> +        if (ret < 0)
>>>>> +            return ret;
>>>>> +        value = 2 * value + ret;
>>>>> +    }
>>>>> +
>>>>> +    return value;
>>>>> +}
>>>>> +
>>>>> +static int pop_length(BitReader *br, AVIOContext *pb)
>>>>> +{
>>>>> +    int ret, n = 1;
>>>>> +
>>>>> +    while ((ret = pop(br, pb)) == 0)
>>>>> +        n++;
>>>>> +
>>>>> +    if (ret < 0)
>>>>> +        return ret;
>>>>> +    return n;
>>>>> +}
>>>>> +
>>>>> +static int read_var_byte(AVFormatContext *s, unsigned *out)
>>>>> +{
>>>>> +    AVIOContext *pb = s->pb;
>>>>> +    unsigned value = 0, data;
>>>>> +
>>>>> +    data = avio_r8(pb);
>>>>> +    if (!(data & 0x80)) {
>>>>> +        *out = data;
>>>>> +        return 0;
>>>>> +    }
>>>>> +
>>>>> +    value = (data & 0x7F) << 7;
>>>>> +    data = avio_r8(pb);
>>>>> +    if (!(data & 0x80)) {
>>>>> +        value |= data;
>>>>> +        *out = value;
>>>>> +        return 0;
>>>>> +    }
>>>>> +
>>>>> +    value = ((data & 0x7F) | value) << 7;
>>>>> +    data = avio_r8(pb);
>>>>> +    if (!(data & 0x80)) {
>>>>> +        value |= data;
>>>>> +        *out = value;
>>>>> +        return 0;
>>>>> +    }
>>>>> +
>>>>> +    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
>>>>> +    *out = value;
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +static int moflex_probe(const AVProbeData *p)
>>>>> +{
>>>>> +    GetByteContext gb;
>>>>> +    int score = 0;
>>>>> +
>>>>> +    bytestream2_init(&gb, p->buf, p->buf_size);
>>>>> +
>>>>> +    if (bytestream2_get_be16(&gb) != 0x4C32)
>>>>> +        return 0;
>>>>> +    score += 10;
>>>>> +
>>>>> +    bytestream2_skip(&gb, 10);
>>>>> +    if (bytestream2_get_be16(&gb) == 0)
>>>>> +        return 0;
>>>>> +    score += 5;
>>>>> +
>>>>> +    while (bytestream2_get_bytes_left(&gb) > 0) {
>>>>> +        int type = bytestream2_get_byte(&gb);
>>>>> +        int size = bytestream2_get_byte(&gb);
>>>>> +
>>>>> +        if (type == 0) {
>>>>> +            score += 5 * (size == 0);
>>>>> +            break;
>>>>> +        }
>>>>> +        if ((type == 1 && size == 12) ||
>>>>> +            (type == 2 && size ==  6) ||
>>>>> +            (type == 3 && size == 13) ||
>>>>> +            (type == 4 && size ==  2))
>>>>> +            score += 20;
>>>>> +        bytestream2_skip(&gb, size);
>>>>> +    }
>>>>> +
>>>>> +    return FFMIN(AVPROBE_SCORE_MAX, score);
>>>>> +}
>>>>> +
>>>>> +static int moflex_read_sync(AVFormatContext *s)
>>>>> +{
>>>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>>>> +    AVIOContext *pb = s->pb;
>>>>> +
>>>>> +    if (avio_rb16(pb) != 0x4C32) {
>>>>> +        if (avio_feof(pb))
>>>>> +            return AVERROR_EOF;
>>>>> +        avio_seek(pb, -2, SEEK_CUR);
>>>>> +        return 1;
>>>>> +    }
>>>>> +
>>>>> +    avio_skip(pb, 2);
>>>>> +    m->ts = avio_rb64(pb);
>>>>> +    m->size = avio_rb16(pb) + 1;
>>>>> +
>>>>> +    while (!avio_feof(pb)) {
>>>>> +        unsigned type, ssize, codec_id = 0;
>>>>> +        unsigned codec_type, width = 0, height = 0, sample_rate = 0,
>>>>> channels = 0;
>>>>> +        int stream_index = -1;
>>>>> +        int format;
>>>>> +        AVRational fps;
>>>>> +
>>>>> +        read_var_byte(s, &type);
>>>>> +        read_var_byte(s, &ssize);
>>>>> +
>>>>> +        switch (type) {
>>>>> +        case 0:
>>>>> +            if (ssize > 0)
>>>>> +                avio_skip(pb, ssize);
>>>>> +            return 0;
>>>>> +        case 2:
>>>>> +            codec_type = AVMEDIA_TYPE_AUDIO;
>>>>> +            stream_index = avio_r8(pb);
>>>>> +            codec_id = avio_r8(pb);
>>>>> +            switch (codec_id) {
>>>>> +            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
>>>>> +            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
>>>>> +            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
>>>>> +            default:
>>>>> +                av_log(s, AV_LOG_ERROR, "Unsupported audio codec:
>>>>> %d\n",
>>>>> codec_id);
>>>>> +                return AVERROR_PATCHWELCOME;
>>>>> +            }
>>>>> +            sample_rate = avio_rb24(pb) + 1;
>>>>> +            channels = avio_r8(pb) + 1;
>>>>> +            break;
>>>>> +        case 1:
>>>>> +        case 3:
>>>>> +            codec_type = AVMEDIA_TYPE_VIDEO;
>>>>> +            stream_index = avio_r8(pb);
>>>>> +            codec_id = avio_r8(pb);
>>>>> +            switch (codec_id) {
>>>>> +            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
>>>>> +            default:
>>>>> +                av_log(s, AV_LOG_ERROR, "Unsupported video codec:
>>>>> %d\n",
>>>>> codec_id);
>>>>> +                return AVERROR_PATCHWELCOME;
>>>>> +            }
>>>>> +            fps.num = avio_rb16(pb);
>>>>> +            fps.den = avio_rb16(pb);
>>>>> +            width = avio_rb16(pb);
>>>>> +            height = avio_rb16(pb);
>>>>> +            format = AV_PIX_FMT_YUV420P;
>>>>> +            avio_skip(pb, type == 3 ? 3 : 2);
>>>>> +            break;
>>>>> +        case 4:
>>>>> +            codec_type = AVMEDIA_TYPE_DATA;
>>>>> +            stream_index = avio_r8(pb);
>>>>> +            avio_skip(pb, 1);
>>>>> +            break;
>>>>> +        }
>>>>> +
>>>>> +        if (stream_index == s->nb_streams) {
>>>>> +            AVStream *st = avformat_new_stream(s, NULL);
>>>>> +
>>>>> +            if (!st)
>>>>> +                return AVERROR(ENOMEM);
>>>>> +
>>>>> +            st->codecpar->codec_type = codec_type;
>>>>> +            st->codecpar->codec_id   = codec_id;
>>>>> +            st->codecpar->width      = width;
>>>>> +            st->codecpar->height     = height;
>>>>> +            st->codecpar->sample_rate= sample_rate;
>>>>> +            st->codecpar->channels   = channels;
>>>>> +            st->codecpar->format     = format;
>>>>> +            st->priv_data            = av_packet_alloc();
>>>>> +            if (!st->priv_data)
>>>>> +                return AVERROR(ENOMEM);
>>>>
>>>> If this allocation fails when reading a packet, you end up with a stream
>>>> without priv_data. If the caller decides to call av_read_frame() again,
>>>> you can get a segfault, because the code for reading a packet presumes
>>>> every stream to have an AVPacket as priv_data.
>>>
>>> No this is huge libavformat bug. NULL pointer dereference when appending
>>> packet.
>>>
>>
>> No it is a bug to call it with pkt == NULL.
> 
> Nope my code is correct.
> 
> av_append_packet is buggy.
> 

No, it's not. (If you think it's buggy, then send a patch for it and see
what others have to say about it.)

>>
>>>>
>>>>> +
>>>>> +            if (sample_rate)
>>>>> +                avpriv_set_pts_info(st, 63, 1, sample_rate);
>>>>> +            else
>>>>> +                avpriv_set_pts_info(st, 63, fps.den, fps.num);
>>>>> +        }
>>>>> +    }
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +static int moflex_read_header(AVFormatContext *s)
>>>>> +{
>>>>> +    int ret;
>>>>> +
>>>>> +    ret = moflex_read_sync(s);
>>>>> +    if (ret < 0)
>>>>> +        return ret;
>>>>> +
>>>>> +    s->ctx_flags |= AVFMTCTX_NOHEADER;
>>>>> +    avio_seek(s->pb, 0, SEEK_SET);
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
>>>>> +{
>>>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>>>> +    AVIOContext *pb = s->pb;
>>>>> +    BitReader *br = &m->br;
>>>>> +    int ret;
>>>>> +
>>>>> +    while (!avio_feof(pb)) {
>>>>> +        if (!m->in_block) {
>>>>> +            m->pos = avio_tell(pb);
>>>>> +
>>>>> +            ret = moflex_read_sync(s);
>>>>> +            if (ret < 0)
>>>>> +                return ret;
>>>>> +
>>>>> +            m->flags = avio_r8(pb);
>>>>> +            if (m->flags & 2)
>>>>> +                avio_skip(pb, 2);
>>>>> +        }
>>>>> +
>>>>> +        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) &&
>>>>> avio_r8(pb)) {
>>>>> +            int stream_index, bits, pkt_size, endframe;
>>>>> +            AVPacket *packet;
>>>>> +
>>>>> +            m->in_block = 1;
>>>>> +
>>>>> +            avio_seek(pb, -1, SEEK_CUR);
>>>>> +            br->pos = br->last = 0;
>>>>> +
>>>>> +            bits = pop_length(br, pb);
>>>>> +            if (bits < 0)
>>>>> +                return bits;
>>>>> +            stream_index = pop_int(br, pb, bits);
>>>>> +            if (stream_index < 0)
>>>>> +                return stream_index;
>>>>> +            if (stream_index >= s->nb_streams)
>>>>> +                return AVERROR_INVALIDDATA;
>>>>> +
>>>>> +            endframe = pop(br, pb);
>>>>> +            if (endframe < 0)
>>>>> +                return endframe;
>>>>> +            if (endframe) {
>>>>> +                bits = pop_length(br, pb);
>>>>> +                if (bits < 0)
>>>>> +                    return bits;
>>>>> +                pop_int(br, pb, bits);
>>>>> +                pop(br, pb);
>>>>> +                bits = pop_length(br, pb);
>>>>> +                if (bits < 0)
>>>>> +                    return bits;
>>>>> +                pop_int(br, pb, bits * 2 + 26);
>>>>> +            }
>>>>> +
>>>>> +            pkt_size = pop_int(br, pb, 13) + 1;
>>>>> +            packet   = s->streams[stream_index]->priv_data;
>>>>> +
>>>>> +            ret = av_append_packet(pb, packet, pkt_size);
>>>>> +            if (endframe) {
>>>>> +                av_packet_move_ref(pkt, packet);
>>>>> +                pkt->pos = m->pos;
>>>>> +                pkt->stream_index = stream_index;
>>>>> +                pkt->flags |= AV_PKT_FLAG_KEY;
>>>>> +                return ret;
>>>>> +            }
>>>>> +        }
>>>>> +
>>>>> +        m->in_block = 0;
>>>>> +
>>>>> +        if (m->flags % 2 == 0)
>>>>> +            avio_seek(pb, m->pos + m->size, SEEK_SET);
>>>>> +    }
>>>>> +
>>>>> +    return AVERROR_EOF;
>>>>> +}
>>>>> +
>>>>> +static int moflex_read_close(AVFormatContext *s)
>>>>> +{
>>>>> +    for (int i = 0; i < s->nb_streams; i++) {
>>>>> +        AVPacket *packet = s->streams[i]->priv_data;
>>>>> +
>>>>> +        av_packet_free(&packet);
>>>>> +        s->streams[i]->priv_data = 0;
>>>>> +    }
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +AVInputFormat ff_moflex_demuxer = {
>>>>> +    .name           = "moflex",
>>>>> +    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
>>>>> +    .priv_data_size = sizeof(MOFLEXDemuxContext),
>>>>> +    .read_probe     = moflex_probe,
>>>>> +    .read_header    = moflex_read_header,
>>>>> +    .read_packet    = moflex_read_packet,
>>>>> +    .read_close     = moflex_read_close,
>>>>> +    .extensions     = "moflex",
>>>>> +    .flags          = AVFMT_GENERIC_INDEX,
>>>>> +};
>>>>>
>>>>
Paul B Mahol Sept. 3, 2020, 10:54 a.m. UTC | #6
On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
> Paul B Mahol:
>> Signed-off-by: Paul B Mahol <onemda@gmail.com>
>> ---
>>  libavformat/Makefile     |   1 +
>>  libavformat/allformats.c |   1 +
>>  libavformat/moflex.c     | 360 +++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 362 insertions(+)
>>  create mode 100644 libavformat/moflex.c
>>
>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>> index cbb33fe37c..1e0ac317e5 100644
>> --- a/libavformat/Makefile
>> +++ b/libavformat/Makefile
>> @@ -319,6 +319,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o
>> riffdec.o
>>  OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
>>  OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
>>  OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
>> +OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
>>  OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o
>> replaygain.o
>>  OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o
>> vpcc.o \
>>                                              movenchint.o mov_chan.o rtp.o
>> \
>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>> index 0aa9dd7198..28331facb9 100644
>> --- a/libavformat/allformats.c
>> +++ b/libavformat/allformats.c
>> @@ -249,6 +249,7 @@ extern AVInputFormat  ff_mlv_demuxer;
>>  extern AVInputFormat  ff_mm_demuxer;
>>  extern AVInputFormat  ff_mmf_demuxer;
>>  extern AVOutputFormat ff_mmf_muxer;
>> +extern AVInputFormat  ff_moflex_demuxer;
>>  extern AVInputFormat  ff_mov_demuxer;
>>  extern AVOutputFormat ff_mov_muxer;
>>  extern AVOutputFormat ff_mp2_muxer;
>> diff --git a/libavformat/moflex.c b/libavformat/moflex.c
>> new file mode 100644
>> index 0000000000..989623396f
>> --- /dev/null
>> +++ b/libavformat/moflex.c
>> @@ -0,0 +1,360 @@
>> +/*
>> + * MOFLEX demuxer
>> + * Copyright (c) 2020 Paul B Mahol
>> + *
>> + * 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
>> + */
>> +
>> +#include "libavcodec/bytestream.h"
>> +
>> +#include "avformat.h"
>> +#include "internal.h"
>> +
>> +typedef struct BitReader {
>> +    unsigned last;
>> +    unsigned pos;
>> +} BitReader;
>> +
>> +typedef struct MOFLEXDemuxContext {
>> +    unsigned size;
>> +    int64_t pos;
>> +    int64_t ts;
>> +    int flags;
>> +    int in_block;
>> +
>> +    BitReader br;
>> +} MOFLEXDemuxContext;
>> +
>> +static int pop(BitReader *br, AVIOContext *pb)
>> +{
>> +    if (avio_feof(pb))
>> +        return AVERROR_EOF;
>> +
>> +    if ((br->pos & 7) == 0)
>> +        br->last = (unsigned)avio_r8(pb) << 24U;
>> +    else
>> +        br->last <<= 1;
>> +
>> +    br->pos++;
>> +    return !!(br->last & 0x80000000);
>> +}
>> +
>> +static int pop_int(BitReader *br, AVIOContext *pb, int n)
>> +{
>> +    int value = 0;
>> +
>> +    for (int i = 0; i < n; i++) {
>> +        int ret = pop(br, pb);
>> +
>> +        if (ret < 0)
>> +            return ret;
>> +        value = 2 * value + ret;
>> +    }
>> +
>> +    return value;
>> +}
>> +
>> +static int pop_length(BitReader *br, AVIOContext *pb)
>> +{
>> +    int ret, n = 1;
>> +
>> +    while ((ret = pop(br, pb)) == 0)
>> +        n++;
>> +
>> +    if (ret < 0)
>> +        return ret;
>> +    return n;
>> +}
>> +
>> +static int read_var_byte(AVFormatContext *s, unsigned *out)
>> +{
>> +    AVIOContext *pb = s->pb;
>> +    unsigned value = 0, data;
>> +
>> +    data = avio_r8(pb);
>> +    if (!(data & 0x80)) {
>> +        *out = data;
>> +        return 0;
>> +    }
>> +
>> +    value = (data & 0x7F) << 7;
>> +    data = avio_r8(pb);
>> +    if (!(data & 0x80)) {
>> +        value |= data;
>> +        *out = value;
>> +        return 0;
>> +    }
>> +
>> +    value = ((data & 0x7F) | value) << 7;
>> +    data = avio_r8(pb);
>> +    if (!(data & 0x80)) {
>> +        value |= data;
>> +        *out = value;
>> +        return 0;
>> +    }
>> +
>> +    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
>> +    *out = value;
>> +
>> +    return 0;
>> +}
>> +
>> +static int moflex_probe(const AVProbeData *p)
>> +{
>> +    GetByteContext gb;
>> +    int score = 0;
>> +
>> +    bytestream2_init(&gb, p->buf, p->buf_size);
>> +
>> +    if (bytestream2_get_be16(&gb) != 0x4C32)
>> +        return 0;
>> +    score += 10;
>> +
>> +    bytestream2_skip(&gb, 10);
>> +    if (bytestream2_get_be16(&gb) == 0)
>> +        return 0;
>> +    score += 5;
>> +
>> +    while (bytestream2_get_bytes_left(&gb) > 0) {
>> +        int type = bytestream2_get_byte(&gb);
>> +        int size = bytestream2_get_byte(&gb);
>> +
>> +        if (type == 0) {
>> +            score += 5 * (size == 0);
>> +            break;
>> +        }
>> +        if ((type == 1 && size == 12) ||
>> +            (type == 2 && size ==  6) ||
>> +            (type == 3 && size == 13) ||
>> +            (type == 4 && size ==  2))
>> +            score += 20;
>> +        bytestream2_skip(&gb, size);
>> +    }
>> +
>> +    return FFMIN(AVPROBE_SCORE_MAX, score);
>> +}
>> +
>> +static int moflex_read_sync(AVFormatContext *s)
>> +{
>> +    MOFLEXDemuxContext *m = s->priv_data;
>> +    AVIOContext *pb = s->pb;
>> +
>> +    if (avio_rb16(pb) != 0x4C32) {
>> +        if (avio_feof(pb))
>> +            return AVERROR_EOF;
>> +        avio_seek(pb, -2, SEEK_CUR);
>> +        return 1;
>> +    }
>> +
>> +    avio_skip(pb, 2);
>> +    m->ts = avio_rb64(pb);
>> +    m->size = avio_rb16(pb) + 1;
>> +
>> +    while (!avio_feof(pb)) {
>> +        unsigned type, ssize, codec_id = 0;
>> +        unsigned codec_type, width = 0, height = 0, sample_rate = 0,
>> channels = 0;
>> +        int stream_index = -1;
>> +        int format;
>> +        AVRational fps;
>> +
>> +        read_var_byte(s, &type);
>> +        read_var_byte(s, &ssize);
>> +
>> +        switch (type) {
>> +        case 0:
>> +            if (ssize > 0)
>> +                avio_skip(pb, ssize);
>> +            return 0;
>> +        case 2:
>> +            codec_type = AVMEDIA_TYPE_AUDIO;
>> +            stream_index = avio_r8(pb);
>> +            codec_id = avio_r8(pb);
>> +            switch (codec_id) {
>> +            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
>> +            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
>> +            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
>> +            default:
>> +                av_log(s, AV_LOG_ERROR, "Unsupported audio codec: %d\n",
>> codec_id);
>> +                return AVERROR_PATCHWELCOME;
>> +            }
>> +            sample_rate = avio_rb24(pb) + 1;
>> +            channels = avio_r8(pb) + 1;
>> +            break;
>> +        case 1:
>> +        case 3:
>> +            codec_type = AVMEDIA_TYPE_VIDEO;
>> +            stream_index = avio_r8(pb);
>> +            codec_id = avio_r8(pb);
>> +            switch (codec_id) {
>> +            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
>> +            default:
>> +                av_log(s, AV_LOG_ERROR, "Unsupported video codec: %d\n",
>> codec_id);
>> +                return AVERROR_PATCHWELCOME;
>> +            }
>> +            fps.num = avio_rb16(pb);
>> +            fps.den = avio_rb16(pb);
>> +            width = avio_rb16(pb);
>> +            height = avio_rb16(pb);
>> +            format = AV_PIX_FMT_YUV420P;
>> +            avio_skip(pb, type == 3 ? 3 : 2);
>> +            break;
>> +        case 4:
>> +            codec_type = AVMEDIA_TYPE_DATA;
>> +            stream_index = avio_r8(pb);
>> +            avio_skip(pb, 1);
>> +            break;
>> +        }
>> +
>> +        if (stream_index == s->nb_streams) {
>> +            AVStream *st = avformat_new_stream(s, NULL);
>> +
>> +            if (!st)
>> +                return AVERROR(ENOMEM);
>> +
>> +            st->codecpar->codec_type = codec_type;
>> +            st->codecpar->codec_id   = codec_id;
>> +            st->codecpar->width      = width;
>> +            st->codecpar->height     = height;
>> +            st->codecpar->sample_rate= sample_rate;
>> +            st->codecpar->channels   = channels;
>> +            st->codecpar->format     = format;
>> +            st->priv_data            = av_packet_alloc();
>> +            if (!st->priv_data)
>> +                return AVERROR(ENOMEM);
>
> If this allocation fails when reading a packet, you end up with a stream
> without priv_data. If the caller decides to call av_read_frame() again,
> you can get a segfault, because the code for reading a packet presumes
> every stream to have an AVPacket as priv_data.

Why should caller call it again after receiving the fatal error?
That is never checked/covered anyway by anything.

I do not need to comply with out of head new standards.
And also checking thing in function itself is much cleaner, and more robust
for all another demuxers and callers, instead of doing it before calling this
function and takes less lines of code.

>
>> +
>> +            if (sample_rate)
>> +                avpriv_set_pts_info(st, 63, 1, sample_rate);
>> +            else
>> +                avpriv_set_pts_info(st, 63, fps.den, fps.num);
>> +        }
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +static int moflex_read_header(AVFormatContext *s)
>> +{
>> +    int ret;
>> +
>> +    ret = moflex_read_sync(s);
>> +    if (ret < 0)
>> +        return ret;
>> +
>> +    s->ctx_flags |= AVFMTCTX_NOHEADER;
>> +    avio_seek(s->pb, 0, SEEK_SET);
>> +
>> +    return 0;
>> +}
>> +
>> +static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
>> +{
>> +    MOFLEXDemuxContext *m = s->priv_data;
>> +    AVIOContext *pb = s->pb;
>> +    BitReader *br = &m->br;
>> +    int ret;
>> +
>> +    while (!avio_feof(pb)) {
>> +        if (!m->in_block) {
>> +            m->pos = avio_tell(pb);
>> +
>> +            ret = moflex_read_sync(s);
>> +            if (ret < 0)
>> +                return ret;
>> +
>> +            m->flags = avio_r8(pb);
>> +            if (m->flags & 2)
>> +                avio_skip(pb, 2);
>> +        }
>> +
>> +        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) &&
>> avio_r8(pb)) {
>> +            int stream_index, bits, pkt_size, endframe;
>> +            AVPacket *packet;
>> +
>> +            m->in_block = 1;
>> +
>> +            avio_seek(pb, -1, SEEK_CUR);
>> +            br->pos = br->last = 0;
>> +
>> +            bits = pop_length(br, pb);
>> +            if (bits < 0)
>> +                return bits;
>> +            stream_index = pop_int(br, pb, bits);
>> +            if (stream_index < 0)
>> +                return stream_index;
>> +            if (stream_index >= s->nb_streams)
>> +                return AVERROR_INVALIDDATA;
>> +
>> +            endframe = pop(br, pb);
>> +            if (endframe < 0)
>> +                return endframe;
>> +            if (endframe) {
>> +                bits = pop_length(br, pb);
>> +                if (bits < 0)
>> +                    return bits;
>> +                pop_int(br, pb, bits);
>> +                pop(br, pb);
>> +                bits = pop_length(br, pb);
>> +                if (bits < 0)
>> +                    return bits;
>> +                pop_int(br, pb, bits * 2 + 26);
>> +            }
>> +
>> +            pkt_size = pop_int(br, pb, 13) + 1;
>> +            packet   = s->streams[stream_index]->priv_data;
>> +
>> +            ret = av_append_packet(pb, packet, pkt_size);
>> +            if (endframe) {
>> +                av_packet_move_ref(pkt, packet);
>> +                pkt->pos = m->pos;
>> +                pkt->stream_index = stream_index;
>> +                pkt->flags |= AV_PKT_FLAG_KEY;
>> +                return ret;
>> +            }
>> +        }
>> +
>> +        m->in_block = 0;
>> +
>> +        if (m->flags % 2 == 0)
>> +            avio_seek(pb, m->pos + m->size, SEEK_SET);
>> +    }
>> +
>> +    return AVERROR_EOF;
>> +}
>> +
>> +static int moflex_read_close(AVFormatContext *s)
>> +{
>> +    for (int i = 0; i < s->nb_streams; i++) {
>> +        AVPacket *packet = s->streams[i]->priv_data;
>> +
>> +        av_packet_free(&packet);
>> +        s->streams[i]->priv_data = 0;
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>> +AVInputFormat ff_moflex_demuxer = {
>> +    .name           = "moflex",
>> +    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
>> +    .priv_data_size = sizeof(MOFLEXDemuxContext),
>> +    .read_probe     = moflex_probe,
>> +    .read_header    = moflex_read_header,
>> +    .read_packet    = moflex_read_packet,
>> +    .read_close     = moflex_read_close,
>> +    .extensions     = "moflex",
>> +    .flags          = AVFMT_GENERIC_INDEX,
>> +};
>>
>
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> ffmpeg-devel@ffmpeg.org
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> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Andreas Rheinhardt Sept. 3, 2020, 11:26 a.m. UTC | #7
Paul B Mahol:
> On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
>> Paul B Mahol:
>>> Signed-off-by: Paul B Mahol <onemda@gmail.com>
>>> ---
>>>  libavformat/Makefile     |   1 +
>>>  libavformat/allformats.c |   1 +
>>>  libavformat/moflex.c     | 360 +++++++++++++++++++++++++++++++++++++++
>>>  3 files changed, 362 insertions(+)
>>>  create mode 100644 libavformat/moflex.c
>>>
>>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>>> index cbb33fe37c..1e0ac317e5 100644
>>> --- a/libavformat/Makefile
>>> +++ b/libavformat/Makefile
>>> @@ -319,6 +319,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o
>>> riffdec.o
>>>  OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
>>>  OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
>>>  OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
>>> +OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
>>>  OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o
>>> replaygain.o
>>>  OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o
>>> vpcc.o \
>>>                                              movenchint.o mov_chan.o rtp.o
>>> \
>>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>>> index 0aa9dd7198..28331facb9 100644
>>> --- a/libavformat/allformats.c
>>> +++ b/libavformat/allformats.c
>>> @@ -249,6 +249,7 @@ extern AVInputFormat  ff_mlv_demuxer;
>>>  extern AVInputFormat  ff_mm_demuxer;
>>>  extern AVInputFormat  ff_mmf_demuxer;
>>>  extern AVOutputFormat ff_mmf_muxer;
>>> +extern AVInputFormat  ff_moflex_demuxer;
>>>  extern AVInputFormat  ff_mov_demuxer;
>>>  extern AVOutputFormat ff_mov_muxer;
>>>  extern AVOutputFormat ff_mp2_muxer;
>>> diff --git a/libavformat/moflex.c b/libavformat/moflex.c
>>> new file mode 100644
>>> index 0000000000..989623396f
>>> --- /dev/null
>>> +++ b/libavformat/moflex.c
>>> @@ -0,0 +1,360 @@
>>> +/*
>>> + * MOFLEX demuxer
>>> + * Copyright (c) 2020 Paul B Mahol
>>> + *
>>> + * 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
>>> + */
>>> +
>>> +#include "libavcodec/bytestream.h"
>>> +
>>> +#include "avformat.h"
>>> +#include "internal.h"
>>> +
>>> +typedef struct BitReader {
>>> +    unsigned last;
>>> +    unsigned pos;
>>> +} BitReader;
>>> +
>>> +typedef struct MOFLEXDemuxContext {
>>> +    unsigned size;
>>> +    int64_t pos;
>>> +    int64_t ts;
>>> +    int flags;
>>> +    int in_block;
>>> +
>>> +    BitReader br;
>>> +} MOFLEXDemuxContext;
>>> +
>>> +static int pop(BitReader *br, AVIOContext *pb)
>>> +{
>>> +    if (avio_feof(pb))
>>> +        return AVERROR_EOF;
>>> +
>>> +    if ((br->pos & 7) == 0)
>>> +        br->last = (unsigned)avio_r8(pb) << 24U;
>>> +    else
>>> +        br->last <<= 1;
>>> +
>>> +    br->pos++;
>>> +    return !!(br->last & 0x80000000);
>>> +}
>>> +
>>> +static int pop_int(BitReader *br, AVIOContext *pb, int n)
>>> +{
>>> +    int value = 0;
>>> +
>>> +    for (int i = 0; i < n; i++) {
>>> +        int ret = pop(br, pb);
>>> +
>>> +        if (ret < 0)
>>> +            return ret;
>>> +        value = 2 * value + ret;
>>> +    }
>>> +
>>> +    return value;
>>> +}
>>> +
>>> +static int pop_length(BitReader *br, AVIOContext *pb)
>>> +{
>>> +    int ret, n = 1;
>>> +
>>> +    while ((ret = pop(br, pb)) == 0)
>>> +        n++;
>>> +
>>> +    if (ret < 0)
>>> +        return ret;
>>> +    return n;
>>> +}
>>> +
>>> +static int read_var_byte(AVFormatContext *s, unsigned *out)
>>> +{
>>> +    AVIOContext *pb = s->pb;
>>> +    unsigned value = 0, data;
>>> +
>>> +    data = avio_r8(pb);
>>> +    if (!(data & 0x80)) {
>>> +        *out = data;
>>> +        return 0;
>>> +    }
>>> +
>>> +    value = (data & 0x7F) << 7;
>>> +    data = avio_r8(pb);
>>> +    if (!(data & 0x80)) {
>>> +        value |= data;
>>> +        *out = value;
>>> +        return 0;
>>> +    }
>>> +
>>> +    value = ((data & 0x7F) | value) << 7;
>>> +    data = avio_r8(pb);
>>> +    if (!(data & 0x80)) {
>>> +        value |= data;
>>> +        *out = value;
>>> +        return 0;
>>> +    }
>>> +
>>> +    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
>>> +    *out = value;
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int moflex_probe(const AVProbeData *p)
>>> +{
>>> +    GetByteContext gb;
>>> +    int score = 0;
>>> +
>>> +    bytestream2_init(&gb, p->buf, p->buf_size);
>>> +
>>> +    if (bytestream2_get_be16(&gb) != 0x4C32)
>>> +        return 0;
>>> +    score += 10;
>>> +
>>> +    bytestream2_skip(&gb, 10);
>>> +    if (bytestream2_get_be16(&gb) == 0)
>>> +        return 0;
>>> +    score += 5;
>>> +
>>> +    while (bytestream2_get_bytes_left(&gb) > 0) {
>>> +        int type = bytestream2_get_byte(&gb);
>>> +        int size = bytestream2_get_byte(&gb);
>>> +
>>> +        if (type == 0) {
>>> +            score += 5 * (size == 0);
>>> +            break;
>>> +        }
>>> +        if ((type == 1 && size == 12) ||
>>> +            (type == 2 && size ==  6) ||
>>> +            (type == 3 && size == 13) ||
>>> +            (type == 4 && size ==  2))
>>> +            score += 20;
>>> +        bytestream2_skip(&gb, size);
>>> +    }
>>> +
>>> +    return FFMIN(AVPROBE_SCORE_MAX, score);
>>> +}
>>> +
>>> +static int moflex_read_sync(AVFormatContext *s)
>>> +{
>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>> +    AVIOContext *pb = s->pb;
>>> +
>>> +    if (avio_rb16(pb) != 0x4C32) {
>>> +        if (avio_feof(pb))
>>> +            return AVERROR_EOF;
>>> +        avio_seek(pb, -2, SEEK_CUR);
>>> +        return 1;
>>> +    }
>>> +
>>> +    avio_skip(pb, 2);
>>> +    m->ts = avio_rb64(pb);
>>> +    m->size = avio_rb16(pb) + 1;
>>> +
>>> +    while (!avio_feof(pb)) {
>>> +        unsigned type, ssize, codec_id = 0;
>>> +        unsigned codec_type, width = 0, height = 0, sample_rate = 0,
>>> channels = 0;
>>> +        int stream_index = -1;
>>> +        int format;
>>> +        AVRational fps;
>>> +
>>> +        read_var_byte(s, &type);
>>> +        read_var_byte(s, &ssize);
>>> +
>>> +        switch (type) {
>>> +        case 0:
>>> +            if (ssize > 0)
>>> +                avio_skip(pb, ssize);
>>> +            return 0;
>>> +        case 2:
>>> +            codec_type = AVMEDIA_TYPE_AUDIO;
>>> +            stream_index = avio_r8(pb);
>>> +            codec_id = avio_r8(pb);
>>> +            switch (codec_id) {
>>> +            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
>>> +            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
>>> +            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
>>> +            default:
>>> +                av_log(s, AV_LOG_ERROR, "Unsupported audio codec: %d\n",
>>> codec_id);
>>> +                return AVERROR_PATCHWELCOME;
>>> +            }
>>> +            sample_rate = avio_rb24(pb) + 1;
>>> +            channels = avio_r8(pb) + 1;
>>> +            break;
>>> +        case 1:
>>> +        case 3:
>>> +            codec_type = AVMEDIA_TYPE_VIDEO;
>>> +            stream_index = avio_r8(pb);
>>> +            codec_id = avio_r8(pb);
>>> +            switch (codec_id) {
>>> +            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
>>> +            default:
>>> +                av_log(s, AV_LOG_ERROR, "Unsupported video codec: %d\n",
>>> codec_id);
>>> +                return AVERROR_PATCHWELCOME;
>>> +            }
>>> +            fps.num = avio_rb16(pb);
>>> +            fps.den = avio_rb16(pb);
>>> +            width = avio_rb16(pb);
>>> +            height = avio_rb16(pb);
>>> +            format = AV_PIX_FMT_YUV420P;
>>> +            avio_skip(pb, type == 3 ? 3 : 2);
>>> +            break;
>>> +        case 4:
>>> +            codec_type = AVMEDIA_TYPE_DATA;
>>> +            stream_index = avio_r8(pb);
>>> +            avio_skip(pb, 1);
>>> +            break;
>>> +        }
>>> +
>>> +        if (stream_index == s->nb_streams) {
>>> +            AVStream *st = avformat_new_stream(s, NULL);
>>> +
>>> +            if (!st)
>>> +                return AVERROR(ENOMEM);
>>> +
>>> +            st->codecpar->codec_type = codec_type;
>>> +            st->codecpar->codec_id   = codec_id;
>>> +            st->codecpar->width      = width;
>>> +            st->codecpar->height     = height;
>>> +            st->codecpar->sample_rate= sample_rate;
>>> +            st->codecpar->channels   = channels;
>>> +            st->codecpar->format     = format;
>>> +            st->priv_data            = av_packet_alloc();
>>> +            if (!st->priv_data)
>>> +                return AVERROR(ENOMEM);
>>
>> If this allocation fails when reading a packet, you end up with a stream
>> without priv_data. If the caller decides to call av_read_frame() again,
>> you can get a segfault, because the code for reading a packet presumes
>> every stream to have an AVPacket as priv_data.
> 
> Why should caller call it again after receiving the fatal error?
> That is never checked/covered anyway by anything.
> 

Where is it documented that AVERROR(ENOMEM) is a fatal error? And upon
receiving said error, the caller could free some memory and try again.

> I do not need to comply with out of head new standards.
> And also checking thing in function itself is much cleaner, and more robust
> for all another demuxers and callers, instead of doing it before calling this
> function and takes less lines of code.
> 

Not really: For the vast majority of other callers, it is clear that the
packet exists, so adding a check only slows them down. Furthermore, from
the point of av_append_packet(), a NULL AVPacket is AVERROR(EINVAL), but
that would not be an appropriate return value for your caller (who has
not set any argument (hence no wrong argument) given that your demuxer
doesn't have any options), so you would have to filter this and
overwrite the error with something else (probably AVERROR(ENOMEM) again)
and this would negate your "less lines of code" argument. The reason for
you not being allowed to return the error code as is is of course that
in this scenario the error originates in the demuxer itself (for using
NULL as AVPacket) and not somewhere else.

>>
>>> +
>>> +            if (sample_rate)
>>> +                avpriv_set_pts_info(st, 63, 1, sample_rate);
>>> +            else
>>> +                avpriv_set_pts_info(st, 63, fps.den, fps.num);
>>> +        }
>>> +    }
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int moflex_read_header(AVFormatContext *s)
>>> +{
>>> +    int ret;
>>> +
>>> +    ret = moflex_read_sync(s);
>>> +    if (ret < 0)
>>> +        return ret;
>>> +
>>> +    s->ctx_flags |= AVFMTCTX_NOHEADER;
>>> +    avio_seek(s->pb, 0, SEEK_SET);
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
>>> +{
>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>> +    AVIOContext *pb = s->pb;
>>> +    BitReader *br = &m->br;
>>> +    int ret;
>>> +
>>> +    while (!avio_feof(pb)) {
>>> +        if (!m->in_block) {
>>> +            m->pos = avio_tell(pb);
>>> +
>>> +            ret = moflex_read_sync(s);
>>> +            if (ret < 0)
>>> +                return ret;
>>> +
>>> +            m->flags = avio_r8(pb);
>>> +            if (m->flags & 2)
>>> +                avio_skip(pb, 2);
>>> +        }
>>> +
>>> +        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) &&
>>> avio_r8(pb)) {
>>> +            int stream_index, bits, pkt_size, endframe;
>>> +            AVPacket *packet;
>>> +
>>> +            m->in_block = 1;
>>> +
>>> +            avio_seek(pb, -1, SEEK_CUR);
>>> +            br->pos = br->last = 0;
>>> +
>>> +            bits = pop_length(br, pb);
>>> +            if (bits < 0)
>>> +                return bits;
>>> +            stream_index = pop_int(br, pb, bits);
>>> +            if (stream_index < 0)
>>> +                return stream_index;
>>> +            if (stream_index >= s->nb_streams)
>>> +                return AVERROR_INVALIDDATA;
>>> +
>>> +            endframe = pop(br, pb);
>>> +            if (endframe < 0)
>>> +                return endframe;
>>> +            if (endframe) {
>>> +                bits = pop_length(br, pb);
>>> +                if (bits < 0)
>>> +                    return bits;
>>> +                pop_int(br, pb, bits);
>>> +                pop(br, pb);
>>> +                bits = pop_length(br, pb);
>>> +                if (bits < 0)
>>> +                    return bits;
>>> +                pop_int(br, pb, bits * 2 + 26);
>>> +            }
>>> +
>>> +            pkt_size = pop_int(br, pb, 13) + 1;
>>> +            packet   = s->streams[stream_index]->priv_data;
>>> +
>>> +            ret = av_append_packet(pb, packet, pkt_size);
>>> +            if (endframe) {
>>> +                av_packet_move_ref(pkt, packet);
>>> +                pkt->pos = m->pos;
>>> +                pkt->stream_index = stream_index;
>>> +                pkt->flags |= AV_PKT_FLAG_KEY;
>>> +                return ret;
>>> +            }
>>> +        }
>>> +
>>> +        m->in_block = 0;
>>> +
>>> +        if (m->flags % 2 == 0)
>>> +            avio_seek(pb, m->pos + m->size, SEEK_SET);
>>> +    }
>>> +
>>> +    return AVERROR_EOF;
>>> +}
>>> +
>>> +static int moflex_read_close(AVFormatContext *s)
>>> +{
>>> +    for (int i = 0; i < s->nb_streams; i++) {
>>> +        AVPacket *packet = s->streams[i]->priv_data;
>>> +
>>> +        av_packet_free(&packet);
>>> +        s->streams[i]->priv_data = 0;
>>> +    }
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +AVInputFormat ff_moflex_demuxer = {
>>> +    .name           = "moflex",
>>> +    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
>>> +    .priv_data_size = sizeof(MOFLEXDemuxContext),
>>> +    .read_probe     = moflex_probe,
>>> +    .read_header    = moflex_read_header,
>>> +    .read_packet    = moflex_read_packet,
>>> +    .read_close     = moflex_read_close,
>>> +    .extensions     = "moflex",
>>> +    .flags          = AVFMT_GENERIC_INDEX,
>>> +};
>>>
>>
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>> ffmpeg-devel@ffmpeg.org
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
>> To unsubscribe, visit link above, or email
>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
> _______________________________________________
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> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> 
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>
Paul B Mahol Sept. 3, 2020, 11:35 a.m. UTC | #8
On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
> Paul B Mahol:
>> On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
>>> Paul B Mahol:
>>>> Signed-off-by: Paul B Mahol <onemda@gmail.com>
>>>> ---
>>>>  libavformat/Makefile     |   1 +
>>>>  libavformat/allformats.c |   1 +
>>>>  libavformat/moflex.c     | 360 +++++++++++++++++++++++++++++++++++++++
>>>>  3 files changed, 362 insertions(+)
>>>>  create mode 100644 libavformat/moflex.c
>>>>
>>>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>>>> index cbb33fe37c..1e0ac317e5 100644
>>>> --- a/libavformat/Makefile
>>>> +++ b/libavformat/Makefile
>>>> @@ -319,6 +319,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o
>>>> riffdec.o
>>>>  OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
>>>>  OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
>>>>  OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
>>>> +OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
>>>>  OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o
>>>> replaygain.o
>>>>  OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o
>>>> vpcc.o \
>>>>                                              movenchint.o mov_chan.o
>>>> rtp.o
>>>> \
>>>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>>>> index 0aa9dd7198..28331facb9 100644
>>>> --- a/libavformat/allformats.c
>>>> +++ b/libavformat/allformats.c
>>>> @@ -249,6 +249,7 @@ extern AVInputFormat  ff_mlv_demuxer;
>>>>  extern AVInputFormat  ff_mm_demuxer;
>>>>  extern AVInputFormat  ff_mmf_demuxer;
>>>>  extern AVOutputFormat ff_mmf_muxer;
>>>> +extern AVInputFormat  ff_moflex_demuxer;
>>>>  extern AVInputFormat  ff_mov_demuxer;
>>>>  extern AVOutputFormat ff_mov_muxer;
>>>>  extern AVOutputFormat ff_mp2_muxer;
>>>> diff --git a/libavformat/moflex.c b/libavformat/moflex.c
>>>> new file mode 100644
>>>> index 0000000000..989623396f
>>>> --- /dev/null
>>>> +++ b/libavformat/moflex.c
>>>> @@ -0,0 +1,360 @@
>>>> +/*
>>>> + * MOFLEX demuxer
>>>> + * Copyright (c) 2020 Paul B Mahol
>>>> + *
>>>> + * 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
>>>> + */
>>>> +
>>>> +#include "libavcodec/bytestream.h"
>>>> +
>>>> +#include "avformat.h"
>>>> +#include "internal.h"
>>>> +
>>>> +typedef struct BitReader {
>>>> +    unsigned last;
>>>> +    unsigned pos;
>>>> +} BitReader;
>>>> +
>>>> +typedef struct MOFLEXDemuxContext {
>>>> +    unsigned size;
>>>> +    int64_t pos;
>>>> +    int64_t ts;
>>>> +    int flags;
>>>> +    int in_block;
>>>> +
>>>> +    BitReader br;
>>>> +} MOFLEXDemuxContext;
>>>> +
>>>> +static int pop(BitReader *br, AVIOContext *pb)
>>>> +{
>>>> +    if (avio_feof(pb))
>>>> +        return AVERROR_EOF;
>>>> +
>>>> +    if ((br->pos & 7) == 0)
>>>> +        br->last = (unsigned)avio_r8(pb) << 24U;
>>>> +    else
>>>> +        br->last <<= 1;
>>>> +
>>>> +    br->pos++;
>>>> +    return !!(br->last & 0x80000000);
>>>> +}
>>>> +
>>>> +static int pop_int(BitReader *br, AVIOContext *pb, int n)
>>>> +{
>>>> +    int value = 0;
>>>> +
>>>> +    for (int i = 0; i < n; i++) {
>>>> +        int ret = pop(br, pb);
>>>> +
>>>> +        if (ret < 0)
>>>> +            return ret;
>>>> +        value = 2 * value + ret;
>>>> +    }
>>>> +
>>>> +    return value;
>>>> +}
>>>> +
>>>> +static int pop_length(BitReader *br, AVIOContext *pb)
>>>> +{
>>>> +    int ret, n = 1;
>>>> +
>>>> +    while ((ret = pop(br, pb)) == 0)
>>>> +        n++;
>>>> +
>>>> +    if (ret < 0)
>>>> +        return ret;
>>>> +    return n;
>>>> +}
>>>> +
>>>> +static int read_var_byte(AVFormatContext *s, unsigned *out)
>>>> +{
>>>> +    AVIOContext *pb = s->pb;
>>>> +    unsigned value = 0, data;
>>>> +
>>>> +    data = avio_r8(pb);
>>>> +    if (!(data & 0x80)) {
>>>> +        *out = data;
>>>> +        return 0;
>>>> +    }
>>>> +
>>>> +    value = (data & 0x7F) << 7;
>>>> +    data = avio_r8(pb);
>>>> +    if (!(data & 0x80)) {
>>>> +        value |= data;
>>>> +        *out = value;
>>>> +        return 0;
>>>> +    }
>>>> +
>>>> +    value = ((data & 0x7F) | value) << 7;
>>>> +    data = avio_r8(pb);
>>>> +    if (!(data & 0x80)) {
>>>> +        value |= data;
>>>> +        *out = value;
>>>> +        return 0;
>>>> +    }
>>>> +
>>>> +    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
>>>> +    *out = value;
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int moflex_probe(const AVProbeData *p)
>>>> +{
>>>> +    GetByteContext gb;
>>>> +    int score = 0;
>>>> +
>>>> +    bytestream2_init(&gb, p->buf, p->buf_size);
>>>> +
>>>> +    if (bytestream2_get_be16(&gb) != 0x4C32)
>>>> +        return 0;
>>>> +    score += 10;
>>>> +
>>>> +    bytestream2_skip(&gb, 10);
>>>> +    if (bytestream2_get_be16(&gb) == 0)
>>>> +        return 0;
>>>> +    score += 5;
>>>> +
>>>> +    while (bytestream2_get_bytes_left(&gb) > 0) {
>>>> +        int type = bytestream2_get_byte(&gb);
>>>> +        int size = bytestream2_get_byte(&gb);
>>>> +
>>>> +        if (type == 0) {
>>>> +            score += 5 * (size == 0);
>>>> +            break;
>>>> +        }
>>>> +        if ((type == 1 && size == 12) ||
>>>> +            (type == 2 && size ==  6) ||
>>>> +            (type == 3 && size == 13) ||
>>>> +            (type == 4 && size ==  2))
>>>> +            score += 20;
>>>> +        bytestream2_skip(&gb, size);
>>>> +    }
>>>> +
>>>> +    return FFMIN(AVPROBE_SCORE_MAX, score);
>>>> +}
>>>> +
>>>> +static int moflex_read_sync(AVFormatContext *s)
>>>> +{
>>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>>> +    AVIOContext *pb = s->pb;
>>>> +
>>>> +    if (avio_rb16(pb) != 0x4C32) {
>>>> +        if (avio_feof(pb))
>>>> +            return AVERROR_EOF;
>>>> +        avio_seek(pb, -2, SEEK_CUR);
>>>> +        return 1;
>>>> +    }
>>>> +
>>>> +    avio_skip(pb, 2);
>>>> +    m->ts = avio_rb64(pb);
>>>> +    m->size = avio_rb16(pb) + 1;
>>>> +
>>>> +    while (!avio_feof(pb)) {
>>>> +        unsigned type, ssize, codec_id = 0;
>>>> +        unsigned codec_type, width = 0, height = 0, sample_rate = 0,
>>>> channels = 0;
>>>> +        int stream_index = -1;
>>>> +        int format;
>>>> +        AVRational fps;
>>>> +
>>>> +        read_var_byte(s, &type);
>>>> +        read_var_byte(s, &ssize);
>>>> +
>>>> +        switch (type) {
>>>> +        case 0:
>>>> +            if (ssize > 0)
>>>> +                avio_skip(pb, ssize);
>>>> +            return 0;
>>>> +        case 2:
>>>> +            codec_type = AVMEDIA_TYPE_AUDIO;
>>>> +            stream_index = avio_r8(pb);
>>>> +            codec_id = avio_r8(pb);
>>>> +            switch (codec_id) {
>>>> +            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
>>>> +            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
>>>> +            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
>>>> +            default:
>>>> +                av_log(s, AV_LOG_ERROR, "Unsupported audio codec:
>>>> %d\n",
>>>> codec_id);
>>>> +                return AVERROR_PATCHWELCOME;
>>>> +            }
>>>> +            sample_rate = avio_rb24(pb) + 1;
>>>> +            channels = avio_r8(pb) + 1;
>>>> +            break;
>>>> +        case 1:
>>>> +        case 3:
>>>> +            codec_type = AVMEDIA_TYPE_VIDEO;
>>>> +            stream_index = avio_r8(pb);
>>>> +            codec_id = avio_r8(pb);
>>>> +            switch (codec_id) {
>>>> +            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
>>>> +            default:
>>>> +                av_log(s, AV_LOG_ERROR, "Unsupported video codec:
>>>> %d\n",
>>>> codec_id);
>>>> +                return AVERROR_PATCHWELCOME;
>>>> +            }
>>>> +            fps.num = avio_rb16(pb);
>>>> +            fps.den = avio_rb16(pb);
>>>> +            width = avio_rb16(pb);
>>>> +            height = avio_rb16(pb);
>>>> +            format = AV_PIX_FMT_YUV420P;
>>>> +            avio_skip(pb, type == 3 ? 3 : 2);
>>>> +            break;
>>>> +        case 4:
>>>> +            codec_type = AVMEDIA_TYPE_DATA;
>>>> +            stream_index = avio_r8(pb);
>>>> +            avio_skip(pb, 1);
>>>> +            break;
>>>> +        }
>>>> +
>>>> +        if (stream_index == s->nb_streams) {
>>>> +            AVStream *st = avformat_new_stream(s, NULL);
>>>> +
>>>> +            if (!st)
>>>> +                return AVERROR(ENOMEM);
>>>> +
>>>> +            st->codecpar->codec_type = codec_type;
>>>> +            st->codecpar->codec_id   = codec_id;
>>>> +            st->codecpar->width      = width;
>>>> +            st->codecpar->height     = height;
>>>> +            st->codecpar->sample_rate= sample_rate;
>>>> +            st->codecpar->channels   = channels;
>>>> +            st->codecpar->format     = format;
>>>> +            st->priv_data            = av_packet_alloc();
>>>> +            if (!st->priv_data)
>>>> +                return AVERROR(ENOMEM);
>>>
>>> If this allocation fails when reading a packet, you end up with a stream
>>> without priv_data. If the caller decides to call av_read_frame() again,
>>> you can get a segfault, because the code for reading a packet presumes
>>> every stream to have an AVPacket as priv_data.
>>
>> Why should caller call it again after receiving the fatal error?
>> That is never checked/covered anyway by anything.
>>
>
> Where is it documented that AVERROR(ENOMEM) is a fatal error? And upon
> receiving said error, the caller could free some memory and try again.
>
>> I do not need to comply with out of head new standards.
>> And also checking thing in function itself is much cleaner, and more
>> robust
>> for all another demuxers and callers, instead of doing it before calling
>> this
>> function and takes less lines of code.
>>
>
> Not really: For the vast majority of other callers, it is clear that the
> packet exists, so adding a check only slows them down. Furthermore, from
> the point of av_append_packet(), a NULL AVPacket is AVERROR(EINVAL), but
> that would not be an appropriate return value for your caller (who has
> not set any argument (hence no wrong argument) given that your demuxer
> doesn't have any options), so you would have to filter this and
> overwrite the error with something else (probably AVERROR(ENOMEM) again)
> and this would negate your "less lines of code" argument. The reason for
> you not being allowed to return the error code as is is of course that
> in this scenario the error originates in the demuxer itself (for using
> NULL as AVPacket) and not somewhere else.

This does not make sense at all.
You are deeply confused and wrong.

>
>>>
>>>> +
>>>> +            if (sample_rate)
>>>> +                avpriv_set_pts_info(st, 63, 1, sample_rate);
>>>> +            else
>>>> +                avpriv_set_pts_info(st, 63, fps.den, fps.num);
>>>> +        }
>>>> +    }
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int moflex_read_header(AVFormatContext *s)
>>>> +{
>>>> +    int ret;
>>>> +
>>>> +    ret = moflex_read_sync(s);
>>>> +    if (ret < 0)
>>>> +        return ret;
>>>> +
>>>> +    s->ctx_flags |= AVFMTCTX_NOHEADER;
>>>> +    avio_seek(s->pb, 0, SEEK_SET);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
>>>> +{
>>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>>> +    AVIOContext *pb = s->pb;
>>>> +    BitReader *br = &m->br;
>>>> +    int ret;
>>>> +
>>>> +    while (!avio_feof(pb)) {
>>>> +        if (!m->in_block) {
>>>> +            m->pos = avio_tell(pb);
>>>> +
>>>> +            ret = moflex_read_sync(s);
>>>> +            if (ret < 0)
>>>> +                return ret;
>>>> +
>>>> +            m->flags = avio_r8(pb);
>>>> +            if (m->flags & 2)
>>>> +                avio_skip(pb, 2);
>>>> +        }
>>>> +
>>>> +        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) &&
>>>> avio_r8(pb)) {
>>>> +            int stream_index, bits, pkt_size, endframe;
>>>> +            AVPacket *packet;
>>>> +
>>>> +            m->in_block = 1;
>>>> +
>>>> +            avio_seek(pb, -1, SEEK_CUR);
>>>> +            br->pos = br->last = 0;
>>>> +
>>>> +            bits = pop_length(br, pb);
>>>> +            if (bits < 0)
>>>> +                return bits;
>>>> +            stream_index = pop_int(br, pb, bits);
>>>> +            if (stream_index < 0)
>>>> +                return stream_index;
>>>> +            if (stream_index >= s->nb_streams)
>>>> +                return AVERROR_INVALIDDATA;
>>>> +
>>>> +            endframe = pop(br, pb);
>>>> +            if (endframe < 0)
>>>> +                return endframe;
>>>> +            if (endframe) {
>>>> +                bits = pop_length(br, pb);
>>>> +                if (bits < 0)
>>>> +                    return bits;
>>>> +                pop_int(br, pb, bits);
>>>> +                pop(br, pb);
>>>> +                bits = pop_length(br, pb);
>>>> +                if (bits < 0)
>>>> +                    return bits;
>>>> +                pop_int(br, pb, bits * 2 + 26);
>>>> +            }
>>>> +
>>>> +            pkt_size = pop_int(br, pb, 13) + 1;
>>>> +            packet   = s->streams[stream_index]->priv_data;
>>>> +
>>>> +            ret = av_append_packet(pb, packet, pkt_size);
>>>> +            if (endframe) {
>>>> +                av_packet_move_ref(pkt, packet);
>>>> +                pkt->pos = m->pos;
>>>> +                pkt->stream_index = stream_index;
>>>> +                pkt->flags |= AV_PKT_FLAG_KEY;
>>>> +                return ret;
>>>> +            }
>>>> +        }
>>>> +
>>>> +        m->in_block = 0;
>>>> +
>>>> +        if (m->flags % 2 == 0)
>>>> +            avio_seek(pb, m->pos + m->size, SEEK_SET);
>>>> +    }
>>>> +
>>>> +    return AVERROR_EOF;
>>>> +}
>>>> +
>>>> +static int moflex_read_close(AVFormatContext *s)
>>>> +{
>>>> +    for (int i = 0; i < s->nb_streams; i++) {
>>>> +        AVPacket *packet = s->streams[i]->priv_data;
>>>> +
>>>> +        av_packet_free(&packet);
>>>> +        s->streams[i]->priv_data = 0;
>>>> +    }
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +AVInputFormat ff_moflex_demuxer = {
>>>> +    .name           = "moflex",
>>>> +    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
>>>> +    .priv_data_size = sizeof(MOFLEXDemuxContext),
>>>> +    .read_probe     = moflex_probe,
>>>> +    .read_header    = moflex_read_header,
>>>> +    .read_packet    = moflex_read_packet,
>>>> +    .read_close     = moflex_read_close,
>>>> +    .extensions     = "moflex",
>>>> +    .flags          = AVFMT_GENERIC_INDEX,
>>>> +};
>>>>
>>>
>>> _______________________________________________
>>> ffmpeg-devel mailing list
>>> ffmpeg-devel@ffmpeg.org
>>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>>
>>> To unsubscribe, visit link above, or email
>>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>> _______________________________________________
>> ffmpeg-devel mailing list
>> ffmpeg-devel@ffmpeg.org
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
>> To unsubscribe, visit link above, or email
>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>>
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Paul B Mahol Sept. 3, 2020, 11:39 a.m. UTC | #9
On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
> Paul B Mahol:
>> On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
>>> Paul B Mahol:
>>>> Signed-off-by: Paul B Mahol <onemda@gmail.com>
>>>> ---
>>>>  libavformat/Makefile     |   1 +
>>>>  libavformat/allformats.c |   1 +
>>>>  libavformat/moflex.c     | 360 +++++++++++++++++++++++++++++++++++++++
>>>>  3 files changed, 362 insertions(+)
>>>>  create mode 100644 libavformat/moflex.c
>>>>
>>>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>>>> index cbb33fe37c..1e0ac317e5 100644
>>>> --- a/libavformat/Makefile
>>>> +++ b/libavformat/Makefile
>>>> @@ -319,6 +319,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o
>>>> riffdec.o
>>>>  OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
>>>>  OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
>>>>  OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
>>>> +OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
>>>>  OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o
>>>> replaygain.o
>>>>  OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o
>>>> vpcc.o \
>>>>                                              movenchint.o mov_chan.o
>>>> rtp.o
>>>> \
>>>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>>>> index 0aa9dd7198..28331facb9 100644
>>>> --- a/libavformat/allformats.c
>>>> +++ b/libavformat/allformats.c
>>>> @@ -249,6 +249,7 @@ extern AVInputFormat  ff_mlv_demuxer;
>>>>  extern AVInputFormat  ff_mm_demuxer;
>>>>  extern AVInputFormat  ff_mmf_demuxer;
>>>>  extern AVOutputFormat ff_mmf_muxer;
>>>> +extern AVInputFormat  ff_moflex_demuxer;
>>>>  extern AVInputFormat  ff_mov_demuxer;
>>>>  extern AVOutputFormat ff_mov_muxer;
>>>>  extern AVOutputFormat ff_mp2_muxer;
>>>> diff --git a/libavformat/moflex.c b/libavformat/moflex.c
>>>> new file mode 100644
>>>> index 0000000000..989623396f
>>>> --- /dev/null
>>>> +++ b/libavformat/moflex.c
>>>> @@ -0,0 +1,360 @@
>>>> +/*
>>>> + * MOFLEX demuxer
>>>> + * Copyright (c) 2020 Paul B Mahol
>>>> + *
>>>> + * 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
>>>> + */
>>>> +
>>>> +#include "libavcodec/bytestream.h"
>>>> +
>>>> +#include "avformat.h"
>>>> +#include "internal.h"
>>>> +
>>>> +typedef struct BitReader {
>>>> +    unsigned last;
>>>> +    unsigned pos;
>>>> +} BitReader;
>>>> +
>>>> +typedef struct MOFLEXDemuxContext {
>>>> +    unsigned size;
>>>> +    int64_t pos;
>>>> +    int64_t ts;
>>>> +    int flags;
>>>> +    int in_block;
>>>> +
>>>> +    BitReader br;
>>>> +} MOFLEXDemuxContext;
>>>> +
>>>> +static int pop(BitReader *br, AVIOContext *pb)
>>>> +{
>>>> +    if (avio_feof(pb))
>>>> +        return AVERROR_EOF;
>>>> +
>>>> +    if ((br->pos & 7) == 0)
>>>> +        br->last = (unsigned)avio_r8(pb) << 24U;
>>>> +    else
>>>> +        br->last <<= 1;
>>>> +
>>>> +    br->pos++;
>>>> +    return !!(br->last & 0x80000000);
>>>> +}
>>>> +
>>>> +static int pop_int(BitReader *br, AVIOContext *pb, int n)
>>>> +{
>>>> +    int value = 0;
>>>> +
>>>> +    for (int i = 0; i < n; i++) {
>>>> +        int ret = pop(br, pb);
>>>> +
>>>> +        if (ret < 0)
>>>> +            return ret;
>>>> +        value = 2 * value + ret;
>>>> +    }
>>>> +
>>>> +    return value;
>>>> +}
>>>> +
>>>> +static int pop_length(BitReader *br, AVIOContext *pb)
>>>> +{
>>>> +    int ret, n = 1;
>>>> +
>>>> +    while ((ret = pop(br, pb)) == 0)
>>>> +        n++;
>>>> +
>>>> +    if (ret < 0)
>>>> +        return ret;
>>>> +    return n;
>>>> +}
>>>> +
>>>> +static int read_var_byte(AVFormatContext *s, unsigned *out)
>>>> +{
>>>> +    AVIOContext *pb = s->pb;
>>>> +    unsigned value = 0, data;
>>>> +
>>>> +    data = avio_r8(pb);
>>>> +    if (!(data & 0x80)) {
>>>> +        *out = data;
>>>> +        return 0;
>>>> +    }
>>>> +
>>>> +    value = (data & 0x7F) << 7;
>>>> +    data = avio_r8(pb);
>>>> +    if (!(data & 0x80)) {
>>>> +        value |= data;
>>>> +        *out = value;
>>>> +        return 0;
>>>> +    }
>>>> +
>>>> +    value = ((data & 0x7F) | value) << 7;
>>>> +    data = avio_r8(pb);
>>>> +    if (!(data & 0x80)) {
>>>> +        value |= data;
>>>> +        *out = value;
>>>> +        return 0;
>>>> +    }
>>>> +
>>>> +    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
>>>> +    *out = value;
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int moflex_probe(const AVProbeData *p)
>>>> +{
>>>> +    GetByteContext gb;
>>>> +    int score = 0;
>>>> +
>>>> +    bytestream2_init(&gb, p->buf, p->buf_size);
>>>> +
>>>> +    if (bytestream2_get_be16(&gb) != 0x4C32)
>>>> +        return 0;
>>>> +    score += 10;
>>>> +
>>>> +    bytestream2_skip(&gb, 10);
>>>> +    if (bytestream2_get_be16(&gb) == 0)
>>>> +        return 0;
>>>> +    score += 5;
>>>> +
>>>> +    while (bytestream2_get_bytes_left(&gb) > 0) {
>>>> +        int type = bytestream2_get_byte(&gb);
>>>> +        int size = bytestream2_get_byte(&gb);
>>>> +
>>>> +        if (type == 0) {
>>>> +            score += 5 * (size == 0);
>>>> +            break;
>>>> +        }
>>>> +        if ((type == 1 && size == 12) ||
>>>> +            (type == 2 && size ==  6) ||
>>>> +            (type == 3 && size == 13) ||
>>>> +            (type == 4 && size ==  2))
>>>> +            score += 20;
>>>> +        bytestream2_skip(&gb, size);
>>>> +    }
>>>> +
>>>> +    return FFMIN(AVPROBE_SCORE_MAX, score);
>>>> +}
>>>> +
>>>> +static int moflex_read_sync(AVFormatContext *s)
>>>> +{
>>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>>> +    AVIOContext *pb = s->pb;
>>>> +
>>>> +    if (avio_rb16(pb) != 0x4C32) {
>>>> +        if (avio_feof(pb))
>>>> +            return AVERROR_EOF;
>>>> +        avio_seek(pb, -2, SEEK_CUR);
>>>> +        return 1;
>>>> +    }
>>>> +
>>>> +    avio_skip(pb, 2);
>>>> +    m->ts = avio_rb64(pb);
>>>> +    m->size = avio_rb16(pb) + 1;
>>>> +
>>>> +    while (!avio_feof(pb)) {
>>>> +        unsigned type, ssize, codec_id = 0;
>>>> +        unsigned codec_type, width = 0, height = 0, sample_rate = 0,
>>>> channels = 0;
>>>> +        int stream_index = -1;
>>>> +        int format;
>>>> +        AVRational fps;
>>>> +
>>>> +        read_var_byte(s, &type);
>>>> +        read_var_byte(s, &ssize);
>>>> +
>>>> +        switch (type) {
>>>> +        case 0:
>>>> +            if (ssize > 0)
>>>> +                avio_skip(pb, ssize);
>>>> +            return 0;
>>>> +        case 2:
>>>> +            codec_type = AVMEDIA_TYPE_AUDIO;
>>>> +            stream_index = avio_r8(pb);
>>>> +            codec_id = avio_r8(pb);
>>>> +            switch (codec_id) {
>>>> +            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
>>>> +            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
>>>> +            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
>>>> +            default:
>>>> +                av_log(s, AV_LOG_ERROR, "Unsupported audio codec:
>>>> %d\n",
>>>> codec_id);
>>>> +                return AVERROR_PATCHWELCOME;
>>>> +            }
>>>> +            sample_rate = avio_rb24(pb) + 1;
>>>> +            channels = avio_r8(pb) + 1;
>>>> +            break;
>>>> +        case 1:
>>>> +        case 3:
>>>> +            codec_type = AVMEDIA_TYPE_VIDEO;
>>>> +            stream_index = avio_r8(pb);
>>>> +            codec_id = avio_r8(pb);
>>>> +            switch (codec_id) {
>>>> +            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
>>>> +            default:
>>>> +                av_log(s, AV_LOG_ERROR, "Unsupported video codec:
>>>> %d\n",
>>>> codec_id);
>>>> +                return AVERROR_PATCHWELCOME;
>>>> +            }
>>>> +            fps.num = avio_rb16(pb);
>>>> +            fps.den = avio_rb16(pb);
>>>> +            width = avio_rb16(pb);
>>>> +            height = avio_rb16(pb);
>>>> +            format = AV_PIX_FMT_YUV420P;
>>>> +            avio_skip(pb, type == 3 ? 3 : 2);
>>>> +            break;
>>>> +        case 4:
>>>> +            codec_type = AVMEDIA_TYPE_DATA;
>>>> +            stream_index = avio_r8(pb);
>>>> +            avio_skip(pb, 1);
>>>> +            break;
>>>> +        }
>>>> +
>>>> +        if (stream_index == s->nb_streams) {
>>>> +            AVStream *st = avformat_new_stream(s, NULL);
>>>> +
>>>> +            if (!st)
>>>> +                return AVERROR(ENOMEM);
>>>> +
>>>> +            st->codecpar->codec_type = codec_type;
>>>> +            st->codecpar->codec_id   = codec_id;
>>>> +            st->codecpar->width      = width;
>>>> +            st->codecpar->height     = height;
>>>> +            st->codecpar->sample_rate= sample_rate;
>>>> +            st->codecpar->channels   = channels;
>>>> +            st->codecpar->format     = format;
>>>> +            st->priv_data            = av_packet_alloc();
>>>> +            if (!st->priv_data)
>>>> +                return AVERROR(ENOMEM);
>>>
>>> If this allocation fails when reading a packet, you end up with a stream
>>> without priv_data. If the caller decides to call av_read_frame() again,
>>> you can get a segfault, because the code for reading a packet presumes
>>> every stream to have an AVPacket as priv_data.
>>
>> Why should caller call it again after receiving the fatal error?
>> That is never checked/covered anyway by anything.
>>
>
> Where is it documented that AVERROR(ENOMEM) is a fatal error? And upon
> receiving said error, the caller could free some memory and try again.

You are reinterpreting reality in your own way.
FFmpeg aborts on this error. Thus error is fatal.
No demuxer/decoder continues on encountering negative return value,
except EOF case.
You never provided arguments against my other remarks. Thus your reasoning is
invalid.

>
>> I do not need to comply with out of head new standards.
>> And also checking thing in function itself is much cleaner, and more
>> robust
>> for all another demuxers and callers, instead of doing it before calling
>> this
>> function and takes less lines of code.
>>
>
> Not really: For the vast majority of other callers, it is clear that the
> packet exists, so adding a check only slows them down. Furthermore, from
> the point of av_append_packet(), a NULL AVPacket is AVERROR(EINVAL), but
> that would not be an appropriate return value for your caller (who has
> not set any argument (hence no wrong argument) given that your demuxer
> doesn't have any options), so you would have to filter this and
> overwrite the error with something else (probably AVERROR(ENOMEM) again)
> and this would negate your "less lines of code" argument. The reason for
> you not being allowed to return the error code as is is of course that
> in this scenario the error originates in the demuxer itself (for using
> NULL as AVPacket) and not somewhere else.
>
>>>
>>>> +
>>>> +            if (sample_rate)
>>>> +                avpriv_set_pts_info(st, 63, 1, sample_rate);
>>>> +            else
>>>> +                avpriv_set_pts_info(st, 63, fps.den, fps.num);
>>>> +        }
>>>> +    }
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int moflex_read_header(AVFormatContext *s)
>>>> +{
>>>> +    int ret;
>>>> +
>>>> +    ret = moflex_read_sync(s);
>>>> +    if (ret < 0)
>>>> +        return ret;
>>>> +
>>>> +    s->ctx_flags |= AVFMTCTX_NOHEADER;
>>>> +    avio_seek(s->pb, 0, SEEK_SET);
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
>>>> +{
>>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>>> +    AVIOContext *pb = s->pb;
>>>> +    BitReader *br = &m->br;
>>>> +    int ret;
>>>> +
>>>> +    while (!avio_feof(pb)) {
>>>> +        if (!m->in_block) {
>>>> +            m->pos = avio_tell(pb);
>>>> +
>>>> +            ret = moflex_read_sync(s);
>>>> +            if (ret < 0)
>>>> +                return ret;
>>>> +
>>>> +            m->flags = avio_r8(pb);
>>>> +            if (m->flags & 2)
>>>> +                avio_skip(pb, 2);
>>>> +        }
>>>> +
>>>> +        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) &&
>>>> avio_r8(pb)) {
>>>> +            int stream_index, bits, pkt_size, endframe;
>>>> +            AVPacket *packet;
>>>> +
>>>> +            m->in_block = 1;
>>>> +
>>>> +            avio_seek(pb, -1, SEEK_CUR);
>>>> +            br->pos = br->last = 0;
>>>> +
>>>> +            bits = pop_length(br, pb);
>>>> +            if (bits < 0)
>>>> +                return bits;
>>>> +            stream_index = pop_int(br, pb, bits);
>>>> +            if (stream_index < 0)
>>>> +                return stream_index;
>>>> +            if (stream_index >= s->nb_streams)
>>>> +                return AVERROR_INVALIDDATA;
>>>> +
>>>> +            endframe = pop(br, pb);
>>>> +            if (endframe < 0)
>>>> +                return endframe;
>>>> +            if (endframe) {
>>>> +                bits = pop_length(br, pb);
>>>> +                if (bits < 0)
>>>> +                    return bits;
>>>> +                pop_int(br, pb, bits);
>>>> +                pop(br, pb);
>>>> +                bits = pop_length(br, pb);
>>>> +                if (bits < 0)
>>>> +                    return bits;
>>>> +                pop_int(br, pb, bits * 2 + 26);
>>>> +            }
>>>> +
>>>> +            pkt_size = pop_int(br, pb, 13) + 1;
>>>> +            packet   = s->streams[stream_index]->priv_data;
>>>> +
>>>> +            ret = av_append_packet(pb, packet, pkt_size);
>>>> +            if (endframe) {
>>>> +                av_packet_move_ref(pkt, packet);
>>>> +                pkt->pos = m->pos;
>>>> +                pkt->stream_index = stream_index;
>>>> +                pkt->flags |= AV_PKT_FLAG_KEY;
>>>> +                return ret;
>>>> +            }
>>>> +        }
>>>> +
>>>> +        m->in_block = 0;
>>>> +
>>>> +        if (m->flags % 2 == 0)
>>>> +            avio_seek(pb, m->pos + m->size, SEEK_SET);
>>>> +    }
>>>> +
>>>> +    return AVERROR_EOF;
>>>> +}
>>>> +
>>>> +static int moflex_read_close(AVFormatContext *s)
>>>> +{
>>>> +    for (int i = 0; i < s->nb_streams; i++) {
>>>> +        AVPacket *packet = s->streams[i]->priv_data;
>>>> +
>>>> +        av_packet_free(&packet);
>>>> +        s->streams[i]->priv_data = 0;
>>>> +    }
>>>> +
>>>> +    return 0;
>>>> +}
>>>> +
>>>> +AVInputFormat ff_moflex_demuxer = {
>>>> +    .name           = "moflex",
>>>> +    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
>>>> +    .priv_data_size = sizeof(MOFLEXDemuxContext),
>>>> +    .read_probe     = moflex_probe,
>>>> +    .read_header    = moflex_read_header,
>>>> +    .read_packet    = moflex_read_packet,
>>>> +    .read_close     = moflex_read_close,
>>>> +    .extensions     = "moflex",
>>>> +    .flags          = AVFMT_GENERIC_INDEX,
>>>> +};
>>>>
>>>
>>> _______________________________________________
>>> ffmpeg-devel mailing list
>>> ffmpeg-devel@ffmpeg.org
>>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>>
>>> To unsubscribe, visit link above, or email
>>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>> _______________________________________________
>> ffmpeg-devel mailing list
>> ffmpeg-devel@ffmpeg.org
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
>> To unsubscribe, visit link above, or email
>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>>
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
Andreas Rheinhardt Sept. 3, 2020, 11:57 a.m. UTC | #10
Paul B Mahol:
> On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
>> Paul B Mahol:
>>> On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
>>>> Paul B Mahol:
>>>>> Signed-off-by: Paul B Mahol <onemda@gmail.com>
>>>>> ---
>>>>>  libavformat/Makefile     |   1 +
>>>>>  libavformat/allformats.c |   1 +
>>>>>  libavformat/moflex.c     | 360 +++++++++++++++++++++++++++++++++++++++
>>>>>  3 files changed, 362 insertions(+)
>>>>>  create mode 100644 libavformat/moflex.c
>>>>>
>>>>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>>>>> index cbb33fe37c..1e0ac317e5 100644
>>>>> --- a/libavformat/Makefile
>>>>> +++ b/libavformat/Makefile
>>>>> @@ -319,6 +319,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o
>>>>> riffdec.o
>>>>>  OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
>>>>>  OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
>>>>>  OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
>>>>> +OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
>>>>>  OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o
>>>>> replaygain.o
>>>>>  OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o
>>>>> vpcc.o \
>>>>>                                              movenchint.o mov_chan.o
>>>>> rtp.o
>>>>> \
>>>>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>>>>> index 0aa9dd7198..28331facb9 100644
>>>>> --- a/libavformat/allformats.c
>>>>> +++ b/libavformat/allformats.c
>>>>> @@ -249,6 +249,7 @@ extern AVInputFormat  ff_mlv_demuxer;
>>>>>  extern AVInputFormat  ff_mm_demuxer;
>>>>>  extern AVInputFormat  ff_mmf_demuxer;
>>>>>  extern AVOutputFormat ff_mmf_muxer;
>>>>> +extern AVInputFormat  ff_moflex_demuxer;
>>>>>  extern AVInputFormat  ff_mov_demuxer;
>>>>>  extern AVOutputFormat ff_mov_muxer;
>>>>>  extern AVOutputFormat ff_mp2_muxer;
>>>>> diff --git a/libavformat/moflex.c b/libavformat/moflex.c
>>>>> new file mode 100644
>>>>> index 0000000000..989623396f
>>>>> --- /dev/null
>>>>> +++ b/libavformat/moflex.c
>>>>> @@ -0,0 +1,360 @@
>>>>> +/*
>>>>> + * MOFLEX demuxer
>>>>> + * Copyright (c) 2020 Paul B Mahol
>>>>> + *
>>>>> + * 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
>>>>> + */
>>>>> +
>>>>> +#include "libavcodec/bytestream.h"
>>>>> +
>>>>> +#include "avformat.h"
>>>>> +#include "internal.h"
>>>>> +
>>>>> +typedef struct BitReader {
>>>>> +    unsigned last;
>>>>> +    unsigned pos;
>>>>> +} BitReader;
>>>>> +
>>>>> +typedef struct MOFLEXDemuxContext {
>>>>> +    unsigned size;
>>>>> +    int64_t pos;
>>>>> +    int64_t ts;
>>>>> +    int flags;
>>>>> +    int in_block;
>>>>> +
>>>>> +    BitReader br;
>>>>> +} MOFLEXDemuxContext;
>>>>> +
>>>>> +static int pop(BitReader *br, AVIOContext *pb)
>>>>> +{
>>>>> +    if (avio_feof(pb))
>>>>> +        return AVERROR_EOF;
>>>>> +
>>>>> +    if ((br->pos & 7) == 0)
>>>>> +        br->last = (unsigned)avio_r8(pb) << 24U;
>>>>> +    else
>>>>> +        br->last <<= 1;
>>>>> +
>>>>> +    br->pos++;
>>>>> +    return !!(br->last & 0x80000000);
>>>>> +}
>>>>> +
>>>>> +static int pop_int(BitReader *br, AVIOContext *pb, int n)
>>>>> +{
>>>>> +    int value = 0;
>>>>> +
>>>>> +    for (int i = 0; i < n; i++) {
>>>>> +        int ret = pop(br, pb);
>>>>> +
>>>>> +        if (ret < 0)
>>>>> +            return ret;
>>>>> +        value = 2 * value + ret;
>>>>> +    }
>>>>> +
>>>>> +    return value;
>>>>> +}
>>>>> +
>>>>> +static int pop_length(BitReader *br, AVIOContext *pb)
>>>>> +{
>>>>> +    int ret, n = 1;
>>>>> +
>>>>> +    while ((ret = pop(br, pb)) == 0)
>>>>> +        n++;
>>>>> +
>>>>> +    if (ret < 0)
>>>>> +        return ret;
>>>>> +    return n;
>>>>> +}
>>>>> +
>>>>> +static int read_var_byte(AVFormatContext *s, unsigned *out)
>>>>> +{
>>>>> +    AVIOContext *pb = s->pb;
>>>>> +    unsigned value = 0, data;
>>>>> +
>>>>> +    data = avio_r8(pb);
>>>>> +    if (!(data & 0x80)) {
>>>>> +        *out = data;
>>>>> +        return 0;
>>>>> +    }
>>>>> +
>>>>> +    value = (data & 0x7F) << 7;
>>>>> +    data = avio_r8(pb);
>>>>> +    if (!(data & 0x80)) {
>>>>> +        value |= data;
>>>>> +        *out = value;
>>>>> +        return 0;
>>>>> +    }
>>>>> +
>>>>> +    value = ((data & 0x7F) | value) << 7;
>>>>> +    data = avio_r8(pb);
>>>>> +    if (!(data & 0x80)) {
>>>>> +        value |= data;
>>>>> +        *out = value;
>>>>> +        return 0;
>>>>> +    }
>>>>> +
>>>>> +    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
>>>>> +    *out = value;
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +static int moflex_probe(const AVProbeData *p)
>>>>> +{
>>>>> +    GetByteContext gb;
>>>>> +    int score = 0;
>>>>> +
>>>>> +    bytestream2_init(&gb, p->buf, p->buf_size);
>>>>> +
>>>>> +    if (bytestream2_get_be16(&gb) != 0x4C32)
>>>>> +        return 0;
>>>>> +    score += 10;
>>>>> +
>>>>> +    bytestream2_skip(&gb, 10);
>>>>> +    if (bytestream2_get_be16(&gb) == 0)
>>>>> +        return 0;
>>>>> +    score += 5;
>>>>> +
>>>>> +    while (bytestream2_get_bytes_left(&gb) > 0) {
>>>>> +        int type = bytestream2_get_byte(&gb);
>>>>> +        int size = bytestream2_get_byte(&gb);
>>>>> +
>>>>> +        if (type == 0) {
>>>>> +            score += 5 * (size == 0);
>>>>> +            break;
>>>>> +        }
>>>>> +        if ((type == 1 && size == 12) ||
>>>>> +            (type == 2 && size ==  6) ||
>>>>> +            (type == 3 && size == 13) ||
>>>>> +            (type == 4 && size ==  2))
>>>>> +            score += 20;
>>>>> +        bytestream2_skip(&gb, size);
>>>>> +    }
>>>>> +
>>>>> +    return FFMIN(AVPROBE_SCORE_MAX, score);
>>>>> +}
>>>>> +
>>>>> +static int moflex_read_sync(AVFormatContext *s)
>>>>> +{
>>>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>>>> +    AVIOContext *pb = s->pb;
>>>>> +
>>>>> +    if (avio_rb16(pb) != 0x4C32) {
>>>>> +        if (avio_feof(pb))
>>>>> +            return AVERROR_EOF;
>>>>> +        avio_seek(pb, -2, SEEK_CUR);
>>>>> +        return 1;
>>>>> +    }
>>>>> +
>>>>> +    avio_skip(pb, 2);
>>>>> +    m->ts = avio_rb64(pb);
>>>>> +    m->size = avio_rb16(pb) + 1;
>>>>> +
>>>>> +    while (!avio_feof(pb)) {
>>>>> +        unsigned type, ssize, codec_id = 0;
>>>>> +        unsigned codec_type, width = 0, height = 0, sample_rate = 0,
>>>>> channels = 0;
>>>>> +        int stream_index = -1;
>>>>> +        int format;
>>>>> +        AVRational fps;
>>>>> +
>>>>> +        read_var_byte(s, &type);
>>>>> +        read_var_byte(s, &ssize);
>>>>> +
>>>>> +        switch (type) {
>>>>> +        case 0:
>>>>> +            if (ssize > 0)
>>>>> +                avio_skip(pb, ssize);
>>>>> +            return 0;
>>>>> +        case 2:
>>>>> +            codec_type = AVMEDIA_TYPE_AUDIO;
>>>>> +            stream_index = avio_r8(pb);
>>>>> +            codec_id = avio_r8(pb);
>>>>> +            switch (codec_id) {
>>>>> +            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
>>>>> +            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
>>>>> +            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
>>>>> +            default:
>>>>> +                av_log(s, AV_LOG_ERROR, "Unsupported audio codec:
>>>>> %d\n",
>>>>> codec_id);
>>>>> +                return AVERROR_PATCHWELCOME;
>>>>> +            }
>>>>> +            sample_rate = avio_rb24(pb) + 1;
>>>>> +            channels = avio_r8(pb) + 1;
>>>>> +            break;
>>>>> +        case 1:
>>>>> +        case 3:
>>>>> +            codec_type = AVMEDIA_TYPE_VIDEO;
>>>>> +            stream_index = avio_r8(pb);
>>>>> +            codec_id = avio_r8(pb);
>>>>> +            switch (codec_id) {
>>>>> +            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
>>>>> +            default:
>>>>> +                av_log(s, AV_LOG_ERROR, "Unsupported video codec:
>>>>> %d\n",
>>>>> codec_id);
>>>>> +                return AVERROR_PATCHWELCOME;
>>>>> +            }
>>>>> +            fps.num = avio_rb16(pb);
>>>>> +            fps.den = avio_rb16(pb);
>>>>> +            width = avio_rb16(pb);
>>>>> +            height = avio_rb16(pb);
>>>>> +            format = AV_PIX_FMT_YUV420P;
>>>>> +            avio_skip(pb, type == 3 ? 3 : 2);
>>>>> +            break;
>>>>> +        case 4:
>>>>> +            codec_type = AVMEDIA_TYPE_DATA;
>>>>> +            stream_index = avio_r8(pb);
>>>>> +            avio_skip(pb, 1);
>>>>> +            break;
>>>>> +        }
>>>>> +
>>>>> +        if (stream_index == s->nb_streams) {
>>>>> +            AVStream *st = avformat_new_stream(s, NULL);
>>>>> +
>>>>> +            if (!st)
>>>>> +                return AVERROR(ENOMEM);
>>>>> +
>>>>> +            st->codecpar->codec_type = codec_type;
>>>>> +            st->codecpar->codec_id   = codec_id;
>>>>> +            st->codecpar->width      = width;
>>>>> +            st->codecpar->height     = height;
>>>>> +            st->codecpar->sample_rate= sample_rate;
>>>>> +            st->codecpar->channels   = channels;
>>>>> +            st->codecpar->format     = format;
>>>>> +            st->priv_data            = av_packet_alloc();
>>>>> +            if (!st->priv_data)
>>>>> +                return AVERROR(ENOMEM);
>>>>
>>>> If this allocation fails when reading a packet, you end up with a stream
>>>> without priv_data. If the caller decides to call av_read_frame() again,
>>>> you can get a segfault, because the code for reading a packet presumes
>>>> every stream to have an AVPacket as priv_data.
>>>
>>> Why should caller call it again after receiving the fatal error?
>>> That is never checked/covered anyway by anything.
>>>
>>
>> Where is it documented that AVERROR(ENOMEM) is a fatal error? And upon
>> receiving said error, the caller could free some memory and try again.
> 
> You are reinterpreting reality in your own way.
> FFmpeg aborts on this error. Thus error is fatal.

What the FFmpeg cli tool does, is irrelevant in this case. Only
libavformat documentation would be relevant here.

> No demuxer/decoder continues on encountering negative return value,
> except EOF case.

They continue if you call them again. FFmpeg cli even has the xerror
option to control this.

> You never provided arguments against my other remarks. Thus your reasoning is
> invalid.
> 
>>
>>> I do not need to comply with out of head new standards.
>>> And also checking thing in function itself is much cleaner, and more
>>> robust
>>> for all another demuxers and callers, instead of doing it before calling
>>> this
>>> function and takes less lines of code.
>>>
>>
>> Not really: For the vast majority of other callers, it is clear that the
>> packet exists, so adding a check only slows them down. Furthermore, from
>> the point of av_append_packet(), a NULL AVPacket is AVERROR(EINVAL), but
>> that would not be an appropriate return value for your caller (who has
>> not set any argument (hence no wrong argument) given that your demuxer
>> doesn't have any options), so you would have to filter this and
>> overwrite the error with something else (probably AVERROR(ENOMEM) again)
>> and this would negate your "less lines of code" argument. The reason for
>> you not being allowed to return the error code as is is of course that
>> in this scenario the error originates in the demuxer itself (for using
>> NULL as AVPacket) and not somewhere else.
>>
>>>>
>>>>> +
>>>>> +            if (sample_rate)
>>>>> +                avpriv_set_pts_info(st, 63, 1, sample_rate);
>>>>> +            else
>>>>> +                avpriv_set_pts_info(st, 63, fps.den, fps.num);
>>>>> +        }
>>>>> +    }
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +static int moflex_read_header(AVFormatContext *s)
>>>>> +{
>>>>> +    int ret;
>>>>> +
>>>>> +    ret = moflex_read_sync(s);
>>>>> +    if (ret < 0)
>>>>> +        return ret;
>>>>> +
>>>>> +    s->ctx_flags |= AVFMTCTX_NOHEADER;
>>>>> +    avio_seek(s->pb, 0, SEEK_SET);
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
>>>>> +{
>>>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>>>> +    AVIOContext *pb = s->pb;
>>>>> +    BitReader *br = &m->br;
>>>>> +    int ret;
>>>>> +
>>>>> +    while (!avio_feof(pb)) {
>>>>> +        if (!m->in_block) {
>>>>> +            m->pos = avio_tell(pb);
>>>>> +
>>>>> +            ret = moflex_read_sync(s);
>>>>> +            if (ret < 0)
>>>>> +                return ret;
>>>>> +
>>>>> +            m->flags = avio_r8(pb);
>>>>> +            if (m->flags & 2)
>>>>> +                avio_skip(pb, 2);
>>>>> +        }
>>>>> +
>>>>> +        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) &&
>>>>> avio_r8(pb)) {
>>>>> +            int stream_index, bits, pkt_size, endframe;
>>>>> +            AVPacket *packet;
>>>>> +
>>>>> +            m->in_block = 1;
>>>>> +
>>>>> +            avio_seek(pb, -1, SEEK_CUR);
>>>>> +            br->pos = br->last = 0;
>>>>> +
>>>>> +            bits = pop_length(br, pb);
>>>>> +            if (bits < 0)
>>>>> +                return bits;
>>>>> +            stream_index = pop_int(br, pb, bits);
>>>>> +            if (stream_index < 0)
>>>>> +                return stream_index;
>>>>> +            if (stream_index >= s->nb_streams)
>>>>> +                return AVERROR_INVALIDDATA;
>>>>> +
>>>>> +            endframe = pop(br, pb);
>>>>> +            if (endframe < 0)
>>>>> +                return endframe;
>>>>> +            if (endframe) {
>>>>> +                bits = pop_length(br, pb);
>>>>> +                if (bits < 0)
>>>>> +                    return bits;
>>>>> +                pop_int(br, pb, bits);
>>>>> +                pop(br, pb);
>>>>> +                bits = pop_length(br, pb);
>>>>> +                if (bits < 0)
>>>>> +                    return bits;
>>>>> +                pop_int(br, pb, bits * 2 + 26);
>>>>> +            }
>>>>> +
>>>>> +            pkt_size = pop_int(br, pb, 13) + 1;
>>>>> +            packet   = s->streams[stream_index]->priv_data;
>>>>> +
>>>>> +            ret = av_append_packet(pb, packet, pkt_size);
>>>>> +            if (endframe) {
>>>>> +                av_packet_move_ref(pkt, packet);
>>>>> +                pkt->pos = m->pos;
>>>>> +                pkt->stream_index = stream_index;
>>>>> +                pkt->flags |= AV_PKT_FLAG_KEY;
>>>>> +                return ret;
>>>>> +            }
>>>>> +        }
>>>>> +
>>>>> +        m->in_block = 0;
>>>>> +
>>>>> +        if (m->flags % 2 == 0)
>>>>> +            avio_seek(pb, m->pos + m->size, SEEK_SET);
>>>>> +    }
>>>>> +
>>>>> +    return AVERROR_EOF;
>>>>> +}
>>>>> +
>>>>> +static int moflex_read_close(AVFormatContext *s)
>>>>> +{
>>>>> +    for (int i = 0; i < s->nb_streams; i++) {
>>>>> +        AVPacket *packet = s->streams[i]->priv_data;
>>>>> +
>>>>> +        av_packet_free(&packet);
>>>>> +        s->streams[i]->priv_data = 0;
>>>>> +    }
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +AVInputFormat ff_moflex_demuxer = {
>>>>> +    .name           = "moflex",
>>>>> +    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
>>>>> +    .priv_data_size = sizeof(MOFLEXDemuxContext),
>>>>> +    .read_probe     = moflex_probe,
>>>>> +    .read_header    = moflex_read_header,
>>>>> +    .read_packet    = moflex_read_packet,
>>>>> +    .read_close     = moflex_read_close,
>>>>> +    .extensions     = "moflex",
>>>>> +    .flags          = AVFMT_GENERIC_INDEX,
>>>>> +};
>>>>>
>>>>
>>>> _______________________________________________
>>>> ffmpeg-devel mailing list
>>>> ffmpeg-devel@ffmpeg.org
>>>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>>>
>>>> To unsubscribe, visit link above, or email
>>>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>>> _______________________________________________
>>> ffmpeg-devel mailing list
>>> ffmpeg-devel@ffmpeg.org
>>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>>
>>> To unsubscribe, visit link above, or email
>>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>>>
>>
>> _______________________________________________
>> ffmpeg-devel mailing list
>> ffmpeg-devel@ffmpeg.org
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
>> To unsubscribe, visit link above, or email
>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
> _______________________________________________
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> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> 
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
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Andreas Rheinhardt Sept. 3, 2020, 12:02 p.m. UTC | #11
Paul B Mahol:
> On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
>> Paul B Mahol:
>>> On 9/3/20, Andreas Rheinhardt <andreas.rheinhardt@gmail.com> wrote:
>>>> Paul B Mahol:
>>>>> Signed-off-by: Paul B Mahol <onemda@gmail.com>
>>>>> ---
>>>>>  libavformat/Makefile     |   1 +
>>>>>  libavformat/allformats.c |   1 +
>>>>>  libavformat/moflex.c     | 360 +++++++++++++++++++++++++++++++++++++++
>>>>>  3 files changed, 362 insertions(+)
>>>>>  create mode 100644 libavformat/moflex.c
>>>>>
>>>>> diff --git a/libavformat/Makefile b/libavformat/Makefile
>>>>> index cbb33fe37c..1e0ac317e5 100644
>>>>> --- a/libavformat/Makefile
>>>>> +++ b/libavformat/Makefile
>>>>> @@ -319,6 +319,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o
>>>>> riffdec.o
>>>>>  OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
>>>>>  OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
>>>>>  OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
>>>>> +OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
>>>>>  OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o
>>>>> replaygain.o
>>>>>  OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o
>>>>> vpcc.o \
>>>>>                                              movenchint.o mov_chan.o
>>>>> rtp.o
>>>>> \
>>>>> diff --git a/libavformat/allformats.c b/libavformat/allformats.c
>>>>> index 0aa9dd7198..28331facb9 100644
>>>>> --- a/libavformat/allformats.c
>>>>> +++ b/libavformat/allformats.c
>>>>> @@ -249,6 +249,7 @@ extern AVInputFormat  ff_mlv_demuxer;
>>>>>  extern AVInputFormat  ff_mm_demuxer;
>>>>>  extern AVInputFormat  ff_mmf_demuxer;
>>>>>  extern AVOutputFormat ff_mmf_muxer;
>>>>> +extern AVInputFormat  ff_moflex_demuxer;
>>>>>  extern AVInputFormat  ff_mov_demuxer;
>>>>>  extern AVOutputFormat ff_mov_muxer;
>>>>>  extern AVOutputFormat ff_mp2_muxer;
>>>>> diff --git a/libavformat/moflex.c b/libavformat/moflex.c
>>>>> new file mode 100644
>>>>> index 0000000000..989623396f
>>>>> --- /dev/null
>>>>> +++ b/libavformat/moflex.c
>>>>> @@ -0,0 +1,360 @@
>>>>> +/*
>>>>> + * MOFLEX demuxer
>>>>> + * Copyright (c) 2020 Paul B Mahol
>>>>> + *
>>>>> + * 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
>>>>> + */
>>>>> +
>>>>> +#include "libavcodec/bytestream.h"
>>>>> +
>>>>> +#include "avformat.h"
>>>>> +#include "internal.h"
>>>>> +
>>>>> +typedef struct BitReader {
>>>>> +    unsigned last;
>>>>> +    unsigned pos;
>>>>> +} BitReader;
>>>>> +
>>>>> +typedef struct MOFLEXDemuxContext {
>>>>> +    unsigned size;
>>>>> +    int64_t pos;
>>>>> +    int64_t ts;
>>>>> +    int flags;
>>>>> +    int in_block;
>>>>> +
>>>>> +    BitReader br;
>>>>> +} MOFLEXDemuxContext;
>>>>> +
>>>>> +static int pop(BitReader *br, AVIOContext *pb)
>>>>> +{
>>>>> +    if (avio_feof(pb))
>>>>> +        return AVERROR_EOF;
>>>>> +
>>>>> +    if ((br->pos & 7) == 0)
>>>>> +        br->last = (unsigned)avio_r8(pb) << 24U;
>>>>> +    else
>>>>> +        br->last <<= 1;
>>>>> +
>>>>> +    br->pos++;
>>>>> +    return !!(br->last & 0x80000000);
>>>>> +}
>>>>> +
>>>>> +static int pop_int(BitReader *br, AVIOContext *pb, int n)
>>>>> +{
>>>>> +    int value = 0;
>>>>> +
>>>>> +    for (int i = 0; i < n; i++) {
>>>>> +        int ret = pop(br, pb);
>>>>> +
>>>>> +        if (ret < 0)
>>>>> +            return ret;
>>>>> +        value = 2 * value + ret;
>>>>> +    }
>>>>> +
>>>>> +    return value;
>>>>> +}
>>>>> +
>>>>> +static int pop_length(BitReader *br, AVIOContext *pb)
>>>>> +{
>>>>> +    int ret, n = 1;
>>>>> +
>>>>> +    while ((ret = pop(br, pb)) == 0)
>>>>> +        n++;
>>>>> +
>>>>> +    if (ret < 0)
>>>>> +        return ret;
>>>>> +    return n;
>>>>> +}
>>>>> +
>>>>> +static int read_var_byte(AVFormatContext *s, unsigned *out)
>>>>> +{
>>>>> +    AVIOContext *pb = s->pb;
>>>>> +    unsigned value = 0, data;
>>>>> +
>>>>> +    data = avio_r8(pb);
>>>>> +    if (!(data & 0x80)) {
>>>>> +        *out = data;
>>>>> +        return 0;
>>>>> +    }
>>>>> +
>>>>> +    value = (data & 0x7F) << 7;
>>>>> +    data = avio_r8(pb);
>>>>> +    if (!(data & 0x80)) {
>>>>> +        value |= data;
>>>>> +        *out = value;
>>>>> +        return 0;
>>>>> +    }
>>>>> +
>>>>> +    value = ((data & 0x7F) | value) << 7;
>>>>> +    data = avio_r8(pb);
>>>>> +    if (!(data & 0x80)) {
>>>>> +        value |= data;
>>>>> +        *out = value;
>>>>> +        return 0;
>>>>> +    }
>>>>> +
>>>>> +    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
>>>>> +    *out = value;
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +static int moflex_probe(const AVProbeData *p)
>>>>> +{
>>>>> +    GetByteContext gb;
>>>>> +    int score = 0;
>>>>> +
>>>>> +    bytestream2_init(&gb, p->buf, p->buf_size);
>>>>> +
>>>>> +    if (bytestream2_get_be16(&gb) != 0x4C32)
>>>>> +        return 0;
>>>>> +    score += 10;
>>>>> +
>>>>> +    bytestream2_skip(&gb, 10);
>>>>> +    if (bytestream2_get_be16(&gb) == 0)
>>>>> +        return 0;
>>>>> +    score += 5;
>>>>> +
>>>>> +    while (bytestream2_get_bytes_left(&gb) > 0) {
>>>>> +        int type = bytestream2_get_byte(&gb);
>>>>> +        int size = bytestream2_get_byte(&gb);
>>>>> +
>>>>> +        if (type == 0) {
>>>>> +            score += 5 * (size == 0);
>>>>> +            break;
>>>>> +        }
>>>>> +        if ((type == 1 && size == 12) ||
>>>>> +            (type == 2 && size ==  6) ||
>>>>> +            (type == 3 && size == 13) ||
>>>>> +            (type == 4 && size ==  2))
>>>>> +            score += 20;
>>>>> +        bytestream2_skip(&gb, size);
>>>>> +    }
>>>>> +
>>>>> +    return FFMIN(AVPROBE_SCORE_MAX, score);
>>>>> +}
>>>>> +
>>>>> +static int moflex_read_sync(AVFormatContext *s)
>>>>> +{
>>>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>>>> +    AVIOContext *pb = s->pb;
>>>>> +
>>>>> +    if (avio_rb16(pb) != 0x4C32) {
>>>>> +        if (avio_feof(pb))
>>>>> +            return AVERROR_EOF;
>>>>> +        avio_seek(pb, -2, SEEK_CUR);
>>>>> +        return 1;
>>>>> +    }
>>>>> +
>>>>> +    avio_skip(pb, 2);
>>>>> +    m->ts = avio_rb64(pb);
>>>>> +    m->size = avio_rb16(pb) + 1;
>>>>> +
>>>>> +    while (!avio_feof(pb)) {
>>>>> +        unsigned type, ssize, codec_id = 0;
>>>>> +        unsigned codec_type, width = 0, height = 0, sample_rate = 0,
>>>>> channels = 0;
>>>>> +        int stream_index = -1;
>>>>> +        int format;
>>>>> +        AVRational fps;
>>>>> +
>>>>> +        read_var_byte(s, &type);
>>>>> +        read_var_byte(s, &ssize);
>>>>> +
>>>>> +        switch (type) {
>>>>> +        case 0:
>>>>> +            if (ssize > 0)
>>>>> +                avio_skip(pb, ssize);
>>>>> +            return 0;
>>>>> +        case 2:
>>>>> +            codec_type = AVMEDIA_TYPE_AUDIO;
>>>>> +            stream_index = avio_r8(pb);
>>>>> +            codec_id = avio_r8(pb);
>>>>> +            switch (codec_id) {
>>>>> +            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
>>>>> +            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
>>>>> +            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
>>>>> +            default:
>>>>> +                av_log(s, AV_LOG_ERROR, "Unsupported audio codec:
>>>>> %d\n",
>>>>> codec_id);
>>>>> +                return AVERROR_PATCHWELCOME;
>>>>> +            }
>>>>> +            sample_rate = avio_rb24(pb) + 1;
>>>>> +            channels = avio_r8(pb) + 1;
>>>>> +            break;
>>>>> +        case 1:
>>>>> +        case 3:
>>>>> +            codec_type = AVMEDIA_TYPE_VIDEO;
>>>>> +            stream_index = avio_r8(pb);
>>>>> +            codec_id = avio_r8(pb);
>>>>> +            switch (codec_id) {
>>>>> +            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
>>>>> +            default:
>>>>> +                av_log(s, AV_LOG_ERROR, "Unsupported video codec:
>>>>> %d\n",
>>>>> codec_id);
>>>>> +                return AVERROR_PATCHWELCOME;
>>>>> +            }
>>>>> +            fps.num = avio_rb16(pb);
>>>>> +            fps.den = avio_rb16(pb);
>>>>> +            width = avio_rb16(pb);
>>>>> +            height = avio_rb16(pb);
>>>>> +            format = AV_PIX_FMT_YUV420P;
>>>>> +            avio_skip(pb, type == 3 ? 3 : 2);
>>>>> +            break;
>>>>> +        case 4:
>>>>> +            codec_type = AVMEDIA_TYPE_DATA;
>>>>> +            stream_index = avio_r8(pb);
>>>>> +            avio_skip(pb, 1);
>>>>> +            break;
>>>>> +        }
>>>>> +
>>>>> +        if (stream_index == s->nb_streams) {
>>>>> +            AVStream *st = avformat_new_stream(s, NULL);
>>>>> +
>>>>> +            if (!st)
>>>>> +                return AVERROR(ENOMEM);
>>>>> +
>>>>> +            st->codecpar->codec_type = codec_type;
>>>>> +            st->codecpar->codec_id   = codec_id;
>>>>> +            st->codecpar->width      = width;
>>>>> +            st->codecpar->height     = height;
>>>>> +            st->codecpar->sample_rate= sample_rate;
>>>>> +            st->codecpar->channels   = channels;
>>>>> +            st->codecpar->format     = format;
>>>>> +            st->priv_data            = av_packet_alloc();
>>>>> +            if (!st->priv_data)
>>>>> +                return AVERROR(ENOMEM);
>>>>
>>>> If this allocation fails when reading a packet, you end up with a stream
>>>> without priv_data. If the caller decides to call av_read_frame() again,
>>>> you can get a segfault, because the code for reading a packet presumes
>>>> every stream to have an AVPacket as priv_data.
>>>
>>> Why should caller call it again after receiving the fatal error?
>>> That is never checked/covered anyway by anything.
>>>
>>
>> Where is it documented that AVERROR(ENOMEM) is a fatal error? And upon
>> receiving said error, the caller could free some memory and try again.
>>
>>> I do not need to comply with out of head new standards.
>>> And also checking thing in function itself is much cleaner, and more
>>> robust
>>> for all another demuxers and callers, instead of doing it before calling
>>> this
>>> function and takes less lines of code.
>>>
>>
>> Not really: For the vast majority of other callers, it is clear that the
>> packet exists, so adding a check only slows them down. Furthermore, from
>> the point of av_append_packet(), a NULL AVPacket is AVERROR(EINVAL), but
>> that would not be an appropriate return value for your caller (who has
>> not set any argument (hence no wrong argument) given that your demuxer
>> doesn't have any options), so you would have to filter this and
>> overwrite the error with something else (probably AVERROR(ENOMEM) again)
>> and this would negate your "less lines of code" argument. The reason for
>> you not being allowed to return the error code as is is of course that
>> in this scenario the error originates in the demuxer itself (for using
>> NULL as AVPacket) and not somewhere else.
> 
> This does not make sense at all.
> You are deeply confused and wrong.
> 

Could you elaborate what exactly doesn't make sense at all?

>>
>>>>
>>>>> +
>>>>> +            if (sample_rate)
>>>>> +                avpriv_set_pts_info(st, 63, 1, sample_rate);
>>>>> +            else
>>>>> +                avpriv_set_pts_info(st, 63, fps.den, fps.num);
>>>>> +        }
>>>>> +    }
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +static int moflex_read_header(AVFormatContext *s)
>>>>> +{
>>>>> +    int ret;
>>>>> +
>>>>> +    ret = moflex_read_sync(s);
>>>>> +    if (ret < 0)
>>>>> +        return ret;
>>>>> +
>>>>> +    s->ctx_flags |= AVFMTCTX_NOHEADER;
>>>>> +    avio_seek(s->pb, 0, SEEK_SET);
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
>>>>> +{
>>>>> +    MOFLEXDemuxContext *m = s->priv_data;
>>>>> +    AVIOContext *pb = s->pb;
>>>>> +    BitReader *br = &m->br;
>>>>> +    int ret;
>>>>> +
>>>>> +    while (!avio_feof(pb)) {
>>>>> +        if (!m->in_block) {
>>>>> +            m->pos = avio_tell(pb);
>>>>> +
>>>>> +            ret = moflex_read_sync(s);
>>>>> +            if (ret < 0)
>>>>> +                return ret;
>>>>> +
>>>>> +            m->flags = avio_r8(pb);
>>>>> +            if (m->flags & 2)
>>>>> +                avio_skip(pb, 2);
>>>>> +        }
>>>>> +
>>>>> +        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) &&
>>>>> avio_r8(pb)) {
>>>>> +            int stream_index, bits, pkt_size, endframe;
>>>>> +            AVPacket *packet;
>>>>> +
>>>>> +            m->in_block = 1;
>>>>> +
>>>>> +            avio_seek(pb, -1, SEEK_CUR);
>>>>> +            br->pos = br->last = 0;
>>>>> +
>>>>> +            bits = pop_length(br, pb);
>>>>> +            if (bits < 0)
>>>>> +                return bits;
>>>>> +            stream_index = pop_int(br, pb, bits);
>>>>> +            if (stream_index < 0)
>>>>> +                return stream_index;
>>>>> +            if (stream_index >= s->nb_streams)
>>>>> +                return AVERROR_INVALIDDATA;
>>>>> +
>>>>> +            endframe = pop(br, pb);
>>>>> +            if (endframe < 0)
>>>>> +                return endframe;
>>>>> +            if (endframe) {
>>>>> +                bits = pop_length(br, pb);
>>>>> +                if (bits < 0)
>>>>> +                    return bits;
>>>>> +                pop_int(br, pb, bits);
>>>>> +                pop(br, pb);
>>>>> +                bits = pop_length(br, pb);
>>>>> +                if (bits < 0)
>>>>> +                    return bits;
>>>>> +                pop_int(br, pb, bits * 2 + 26);
>>>>> +            }
>>>>> +
>>>>> +            pkt_size = pop_int(br, pb, 13) + 1;
>>>>> +            packet   = s->streams[stream_index]->priv_data;
>>>>> +
>>>>> +            ret = av_append_packet(pb, packet, pkt_size);
>>>>> +            if (endframe) {
>>>>> +                av_packet_move_ref(pkt, packet);
>>>>> +                pkt->pos = m->pos;
>>>>> +                pkt->stream_index = stream_index;
>>>>> +                pkt->flags |= AV_PKT_FLAG_KEY;
>>>>> +                return ret;
>>>>> +            }
>>>>> +        }
>>>>> +
>>>>> +        m->in_block = 0;
>>>>> +
>>>>> +        if (m->flags % 2 == 0)
>>>>> +            avio_seek(pb, m->pos + m->size, SEEK_SET);
>>>>> +    }
>>>>> +
>>>>> +    return AVERROR_EOF;
>>>>> +}
>>>>> +
>>>>> +static int moflex_read_close(AVFormatContext *s)
>>>>> +{
>>>>> +    for (int i = 0; i < s->nb_streams; i++) {
>>>>> +        AVPacket *packet = s->streams[i]->priv_data;
>>>>> +
>>>>> +        av_packet_free(&packet);
>>>>> +        s->streams[i]->priv_data = 0;
>>>>> +    }
>>>>> +
>>>>> +    return 0;
>>>>> +}
>>>>> +
>>>>> +AVInputFormat ff_moflex_demuxer = {
>>>>> +    .name           = "moflex",
>>>>> +    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
>>>>> +    .priv_data_size = sizeof(MOFLEXDemuxContext),
>>>>> +    .read_probe     = moflex_probe,
>>>>> +    .read_header    = moflex_read_header,
>>>>> +    .read_packet    = moflex_read_packet,
>>>>> +    .read_close     = moflex_read_close,
>>>>> +    .extensions     = "moflex",
>>>>> +    .flags          = AVFMT_GENERIC_INDEX,
>>>>> +};
>>>>>
>>>>
>>>> _______________________________________________
>>>> ffmpeg-devel mailing list
>>>> ffmpeg-devel@ffmpeg.org
>>>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>>>
>>>> To unsubscribe, visit link above, or email
>>>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>>> _______________________________________________
>>> ffmpeg-devel mailing list
>>> ffmpeg-devel@ffmpeg.org
>>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>>
>>> To unsubscribe, visit link above, or email
>>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>>>
>>
>> _______________________________________________
>> ffmpeg-devel mailing list
>> ffmpeg-devel@ffmpeg.org
>> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>>
>> To unsubscribe, visit link above, or email
>> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> 
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>
diff mbox series

Patch

diff --git a/libavformat/Makefile b/libavformat/Makefile
index cbb33fe37c..1e0ac317e5 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -319,6 +319,7 @@  OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o riffdec.o
 OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
 OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
 OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
+OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
 OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o replaygain.o
 OBJS-$(CONFIG_MOV_MUXER)                 += movenc.o av1.o avc.o hevc.o vpcc.o \
                                             movenchint.o mov_chan.o rtp.o \
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index 0aa9dd7198..28331facb9 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -249,6 +249,7 @@  extern AVInputFormat  ff_mlv_demuxer;
 extern AVInputFormat  ff_mm_demuxer;
 extern AVInputFormat  ff_mmf_demuxer;
 extern AVOutputFormat ff_mmf_muxer;
+extern AVInputFormat  ff_moflex_demuxer;
 extern AVInputFormat  ff_mov_demuxer;
 extern AVOutputFormat ff_mov_muxer;
 extern AVOutputFormat ff_mp2_muxer;
diff --git a/libavformat/moflex.c b/libavformat/moflex.c
new file mode 100644
index 0000000000..989623396f
--- /dev/null
+++ b/libavformat/moflex.c
@@ -0,0 +1,360 @@ 
+/*
+ * MOFLEX demuxer
+ * Copyright (c) 2020 Paul B Mahol
+ *
+ * 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
+ */
+
+#include "libavcodec/bytestream.h"
+
+#include "avformat.h"
+#include "internal.h"
+
+typedef struct BitReader {
+    unsigned last;
+    unsigned pos;
+} BitReader;
+
+typedef struct MOFLEXDemuxContext {
+    unsigned size;
+    int64_t pos;
+    int64_t ts;
+    int flags;
+    int in_block;
+
+    BitReader br;
+} MOFLEXDemuxContext;
+
+static int pop(BitReader *br, AVIOContext *pb)
+{
+    if (avio_feof(pb))
+        return AVERROR_EOF;
+
+    if ((br->pos & 7) == 0)
+        br->last = (unsigned)avio_r8(pb) << 24U;
+    else
+        br->last <<= 1;
+
+    br->pos++;
+    return !!(br->last & 0x80000000);
+}
+
+static int pop_int(BitReader *br, AVIOContext *pb, int n)
+{
+    int value = 0;
+
+    for (int i = 0; i < n; i++) {
+        int ret = pop(br, pb);
+
+        if (ret < 0)
+            return ret;
+        value = 2 * value + ret;
+    }
+
+    return value;
+}
+
+static int pop_length(BitReader *br, AVIOContext *pb)
+{
+    int ret, n = 1;
+
+    while ((ret = pop(br, pb)) == 0)
+        n++;
+
+    if (ret < 0)
+        return ret;
+    return n;
+}
+
+static int read_var_byte(AVFormatContext *s, unsigned *out)
+{
+    AVIOContext *pb = s->pb;
+    unsigned value = 0, data;
+
+    data = avio_r8(pb);
+    if (!(data & 0x80)) {
+        *out = data;
+        return 0;
+    }
+
+    value = (data & 0x7F) << 7;
+    data = avio_r8(pb);
+    if (!(data & 0x80)) {
+        value |= data;
+        *out = value;
+        return 0;
+    }
+
+    value = ((data & 0x7F) | value) << 7;
+    data = avio_r8(pb);
+    if (!(data & 0x80)) {
+        value |= data;
+        *out = value;
+        return 0;
+    }
+
+    value = (((data & 0x7F) | value) << 7) | avio_r8(pb);
+    *out = value;
+
+    return 0;
+}
+
+static int moflex_probe(const AVProbeData *p)
+{
+    GetByteContext gb;
+    int score = 0;
+
+    bytestream2_init(&gb, p->buf, p->buf_size);
+
+    if (bytestream2_get_be16(&gb) != 0x4C32)
+        return 0;
+    score += 10;
+
+    bytestream2_skip(&gb, 10);
+    if (bytestream2_get_be16(&gb) == 0)
+        return 0;
+    score += 5;
+
+    while (bytestream2_get_bytes_left(&gb) > 0) {
+        int type = bytestream2_get_byte(&gb);
+        int size = bytestream2_get_byte(&gb);
+
+        if (type == 0) {
+            score += 5 * (size == 0);
+            break;
+        }
+        if ((type == 1 && size == 12) ||
+            (type == 2 && size ==  6) ||
+            (type == 3 && size == 13) ||
+            (type == 4 && size ==  2))
+            score += 20;
+        bytestream2_skip(&gb, size);
+    }
+
+    return FFMIN(AVPROBE_SCORE_MAX, score);
+}
+
+static int moflex_read_sync(AVFormatContext *s)
+{
+    MOFLEXDemuxContext *m = s->priv_data;
+    AVIOContext *pb = s->pb;
+
+    if (avio_rb16(pb) != 0x4C32) {
+        if (avio_feof(pb))
+            return AVERROR_EOF;
+        avio_seek(pb, -2, SEEK_CUR);
+        return 1;
+    }
+
+    avio_skip(pb, 2);
+    m->ts = avio_rb64(pb);
+    m->size = avio_rb16(pb) + 1;
+
+    while (!avio_feof(pb)) {
+        unsigned type, ssize, codec_id = 0;
+        unsigned codec_type, width = 0, height = 0, sample_rate = 0, channels = 0;
+        int stream_index = -1;
+        int format;
+        AVRational fps;
+
+        read_var_byte(s, &type);
+        read_var_byte(s, &ssize);
+
+        switch (type) {
+        case 0:
+            if (ssize > 0)
+                avio_skip(pb, ssize);
+            return 0;
+        case 2:
+            codec_type = AVMEDIA_TYPE_AUDIO;
+            stream_index = avio_r8(pb);
+            codec_id = avio_r8(pb);
+            switch (codec_id) {
+            case 0: codec_id = AV_CODEC_ID_FASTAUDIO; break;
+            case 1: codec_id = AV_CODEC_ID_ADPCM_IMA_MOFLEX; break;
+            case 2: codec_id = AV_CODEC_ID_PCM_S16LE; break;
+            default:
+                av_log(s, AV_LOG_ERROR, "Unsupported audio codec: %d\n", codec_id);
+                return AVERROR_PATCHWELCOME;
+            }
+            sample_rate = avio_rb24(pb) + 1;
+            channels = avio_r8(pb) + 1;
+            break;
+        case 1:
+        case 3:
+            codec_type = AVMEDIA_TYPE_VIDEO;
+            stream_index = avio_r8(pb);
+            codec_id = avio_r8(pb);
+            switch (codec_id) {
+            case 0: codec_id = AV_CODEC_ID_MOBICLIP; break;
+            default:
+                av_log(s, AV_LOG_ERROR, "Unsupported video codec: %d\n", codec_id);
+                return AVERROR_PATCHWELCOME;
+            }
+            fps.num = avio_rb16(pb);
+            fps.den = avio_rb16(pb);
+            width = avio_rb16(pb);
+            height = avio_rb16(pb);
+            format = AV_PIX_FMT_YUV420P;
+            avio_skip(pb, type == 3 ? 3 : 2);
+            break;
+        case 4:
+            codec_type = AVMEDIA_TYPE_DATA;
+            stream_index = avio_r8(pb);
+            avio_skip(pb, 1);
+            break;
+        }
+
+        if (stream_index == s->nb_streams) {
+            AVStream *st = avformat_new_stream(s, NULL);
+
+            if (!st)
+                return AVERROR(ENOMEM);
+
+            st->codecpar->codec_type = codec_type;
+            st->codecpar->codec_id   = codec_id;
+            st->codecpar->width      = width;
+            st->codecpar->height     = height;
+            st->codecpar->sample_rate= sample_rate;
+            st->codecpar->channels   = channels;
+            st->codecpar->format     = format;
+            st->priv_data            = av_packet_alloc();
+            if (!st->priv_data)
+                return AVERROR(ENOMEM);
+
+            if (sample_rate)
+                avpriv_set_pts_info(st, 63, 1, sample_rate);
+            else
+                avpriv_set_pts_info(st, 63, fps.den, fps.num);
+        }
+    }
+
+    return 0;
+}
+
+static int moflex_read_header(AVFormatContext *s)
+{
+    int ret;
+
+    ret = moflex_read_sync(s);
+    if (ret < 0)
+        return ret;
+
+    s->ctx_flags |= AVFMTCTX_NOHEADER;
+    avio_seek(s->pb, 0, SEEK_SET);
+
+    return 0;
+}
+
+static int moflex_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+    MOFLEXDemuxContext *m = s->priv_data;
+    AVIOContext *pb = s->pb;
+    BitReader *br = &m->br;
+    int ret;
+
+    while (!avio_feof(pb)) {
+        if (!m->in_block) {
+            m->pos = avio_tell(pb);
+
+            ret = moflex_read_sync(s);
+            if (ret < 0)
+                return ret;
+
+            m->flags = avio_r8(pb);
+            if (m->flags & 2)
+                avio_skip(pb, 2);
+        }
+
+        while ((avio_tell(pb) < m->pos + m->size) && !avio_feof(pb) && avio_r8(pb)) {
+            int stream_index, bits, pkt_size, endframe;
+            AVPacket *packet;
+
+            m->in_block = 1;
+
+            avio_seek(pb, -1, SEEK_CUR);
+            br->pos = br->last = 0;
+
+            bits = pop_length(br, pb);
+            if (bits < 0)
+                return bits;
+            stream_index = pop_int(br, pb, bits);
+            if (stream_index < 0)
+                return stream_index;
+            if (stream_index >= s->nb_streams)
+                return AVERROR_INVALIDDATA;
+
+            endframe = pop(br, pb);
+            if (endframe < 0)
+                return endframe;
+            if (endframe) {
+                bits = pop_length(br, pb);
+                if (bits < 0)
+                    return bits;
+                pop_int(br, pb, bits);
+                pop(br, pb);
+                bits = pop_length(br, pb);
+                if (bits < 0)
+                    return bits;
+                pop_int(br, pb, bits * 2 + 26);
+            }
+
+            pkt_size = pop_int(br, pb, 13) + 1;
+            packet   = s->streams[stream_index]->priv_data;
+
+            ret = av_append_packet(pb, packet, pkt_size);
+            if (endframe) {
+                av_packet_move_ref(pkt, packet);
+                pkt->pos = m->pos;
+                pkt->stream_index = stream_index;
+                pkt->flags |= AV_PKT_FLAG_KEY;
+                return ret;
+            }
+        }
+
+        m->in_block = 0;
+
+        if (m->flags % 2 == 0)
+            avio_seek(pb, m->pos + m->size, SEEK_SET);
+    }
+
+    return AVERROR_EOF;
+}
+
+static int moflex_read_close(AVFormatContext *s)
+{
+    for (int i = 0; i < s->nb_streams; i++) {
+        AVPacket *packet = s->streams[i]->priv_data;
+
+        av_packet_free(&packet);
+        s->streams[i]->priv_data = 0;
+    }
+
+    return 0;
+}
+
+AVInputFormat ff_moflex_demuxer = {
+    .name           = "moflex",
+    .long_name      = NULL_IF_CONFIG_SMALL("MobiClip MOFLEX"),
+    .priv_data_size = sizeof(MOFLEXDemuxContext),
+    .read_probe     = moflex_probe,
+    .read_header    = moflex_read_header,
+    .read_packet    = moflex_read_packet,
+    .read_close     = moflex_read_close,
+    .extensions     = "moflex",
+    .flags          = AVFMT_GENERIC_INDEX,
+};