[FFmpeg-devel,2/7] lavf/segment: add option to segment by chapter

---
 doc/muxers.texi       |  6 +++++
 libavformat/segment.c | 65 +++++++++++++++++++++++++++++++++++++++++++++++----
 libavformat/version.h |  2 +-
 3 files changed, 67 insertions(+), 6 deletions(-)

2017-05-08 12:36 GMT+08:00 Rodger Combs <rodger.combs@gmail.com>:

> ---
>  doc/muxers.texi       |  6 +++++
>  libavformat/segment.c | 65 ++++++++++++++++++++++++++++++
> +++++++++++++++++----
>  libavformat/version.h |  2 +-
>  3 files changed, 67 insertions(+), 6 deletions(-)
>
> diff --git a/doc/muxers.texi b/doc/muxers.texi
> index 0866142..b80bc68 100644
> --- a/doc/muxers.texi
> +++ b/doc/muxers.texi
> @@ -1521,6 +1521,12 @@ This option specifies to start a new segment
> whenever a reference
>  stream key frame is found and the sequential number (starting from 0)
>  of the frame is greater or equal to the next value in the list.
>
> +@item segment_chapters @var{1|0}
> +Split each chapter into its own segment. Metadata from the chapters
> +will be written to the corresponding segments. If this option is selected
> +and the filename contains tokens in the format @code{$varname$}, they
> +will be replaced by the corresponding metadata values.
> +
>  @item segment_wrap @var{limit}
>  Wrap around segment index once it reaches @var{limit}.
>
> diff --git a/libavformat/segment.c b/libavformat/segment.c
> index 8ec3653..8575d32 100644
> --- a/libavformat/segment.c
> +++ b/libavformat/segment.c
> @@ -108,6 +108,8 @@ typedef struct SegmentContext {
>      int frame_count;       ///< total number of reference frames
>      int segment_frame_count; ///< number of reference frames in the
> segment
>
> +    int split_chapters;    ///< split on chapter markers
> +
>      int64_t time_delta;
>      int  individual_header_trailer; /**< Set by a private option. */
>      int  write_header_trailer; /**< Set by a private option. */
> @@ -188,6 +190,43 @@ static int segment_mux_init(AVFormatContext *s)
>      return 0;
>  }
>
> +static int replace_variables(AVFormatContext *oc)
> +{
> +    char name[sizeof(oc->filename)];
> +    char *p = name;
> +    char *out = oc->filename;
> +    strncpy(name, oc->filename, sizeof(name));
> +    while (*p) {
> +        char c = *p++;
> +        if (c == '$') {
> +            if (*p == '$') {
>
double check?

> +                p++;
> +                goto append;
> +            } else {
> +                int len;
> +                const char *val;
> +                const AVDictionaryEntry *e;
> +                int end = strcspn(p, "$");
> +                if (p[end] == '\0')
> +                    continue;
> +                p[end] = '\0';
> +                e = av_dict_get(oc->metadata, p, NULL, 0);
> +                val = e ? e->value : "(unknown)";
> +                len = strlen(val);
> +                strncpy(out, val, oc->filename + sizeof(oc->filename) - 1
> - out);
>
why not av_strlcpy?

> +                out = FFMIN(oc->filename + sizeof(oc->filename) - 1, out
> + len);
> +                p += end + 1;
> +            }
> +        } else {
> +append:
> +            if (out - oc->filename < sizeof(oc->filename) - 1)
> +                *out++ = c;
> +        }
> +    }
> +    *out = '\0';
> +    return 0;
> +}
> +
>  static int set_segment_filename(AVFormatContext *s)
>  {
>      SegmentContext *seg = s->priv_data;
> @@ -212,6 +251,9 @@ static int set_segment_filename(AVFormatContext *s)
>          return AVERROR(EINVAL);
>      }
>
> +    if (seg->split_chapters)
> +        replace_variables(oc);
> +
>      /* copy modified name in list entry */
>      size = strlen(av_basename(oc->filename)) + 1;
>      if (seg->entry_prefix)
> @@ -238,6 +280,8 @@ static int segment_start(AVFormatContext *s, int
> write_header)
>          if ((err = segment_mux_init(s)) < 0)
>              return err;
>          oc = seg->avf;
> +        if (seg->split_chapters && seg->segment_count < s->nb_chapters &&
> (err = av_dict_copy(&oc->metadata, s->chapters[seg->segment_count]->metadata,
> 0)) < 0)
> +            return err;
>      }
>
>      seg->segment_idx++;
> @@ -661,10 +705,14 @@ static int seg_init(AVFormatContext *s)
>                 "you can use output_ts_offset instead of it\n");
>      }
>
> -    if (!!seg->time_str + !!seg->times_str + !!seg->frames_str > 1) {
> +    if (seg->segment_idx < 0)
> +        seg->segment_idx = seg->split_chapters;
> +
> +    if (!!seg->time_str + !!seg->times_str + !!seg->frames_str +
> !!seg->split_chapters > 1) {
>          av_log(s, AV_LOG_ERROR,
> -               "segment_time, segment_times, and segment_frames options "
> -               "are mutually exclusive, select just one of them\n");
> +               "segment_time, segment_times, segment_frames, and "
> +               "segment_chapters options are mutually exclusive; "
> +               "select just one of them\n");
>          return AVERROR(EINVAL);
>      }
>
> @@ -674,7 +722,7 @@ static int seg_init(AVFormatContext *s)
>      } else if (seg->frames_str) {
>          if ((ret = parse_frames(s, &seg->frames, &seg->nb_frames,
> seg->frames_str)) < 0)
>              return ret;
> -    } else {
> +    } else if (!seg->split_chapters) {
>          /* set default value if not specified */
>          if (!seg->time_str)
>              seg->time_str = av_strdup("2");
> @@ -741,6 +789,9 @@ static int seg_init(AVFormatContext *s)
>      if ((ret = segment_mux_init(s)) < 0)
>          return ret;
>
> +    if (seg->split_chapters && s->nb_chapters && (ret =
> av_dict_copy(&seg->avf->metadata, s->chapters[0]->metadata, 0)) < 0)
> +        return ret;
> +
>      if ((ret = set_segment_filename(s)) < 0)
>          return ret;
>      oc = seg->avf;
> @@ -862,6 +913,9 @@ calc_times:
>      } else if (seg->frames) {
>          start_frame = seg->segment_count < seg->nb_frames ?
>              seg->frames[seg->segment_count] : INT_MAX;
> +    } else if (seg->split_chapters) {
> +        end_pts = seg->segment_count + 1 < s->nb_chapters ?
> +            av_rescale_q(s->chapters[seg->segment_count]->end,
> s->chapters[seg->segment_count]->time_base, AV_TIME_BASE_Q) : INT64_MAX;
>      } else {
>          if (seg->use_clocktime) {
>              int64_t avgt = av_gettime();
> @@ -1044,9 +1098,10 @@ static const AVOption options[] = {
>      { "segment_time_delta","set approximation value used for the segment
> times", OFFSET(time_delta), AV_OPT_TYPE_DURATION, {.i64 = 0}, 0, 0, E },
>      { "segment_times",     "set segment split time points",
> OFFSET(times_str),AV_OPT_TYPE_STRING,{.str = NULL},  0, 0,       E },
>      { "segment_frames",    "set segment split frame numbers",
> OFFSET(frames_str),AV_OPT_TYPE_STRING,{.str = NULL},  0, 0,       E },
> +    { "segment_chapters",  "split segments on chapter markers",
> OFFSET(split_chapters), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, E },
>      { "segment_wrap",      "set number after which the index wraps",
>  OFFSET(segment_idx_wrap), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, E },
>      { "segment_list_entry_prefix", "set base url prefix for segments",
> OFFSET(entry_prefix), AV_OPT_TYPE_STRING,  {.str = NULL}, 0, 0, E },
> -    { "segment_start_number", "set the sequence number of the first
> segment", OFFSET(segment_idx), AV_OPT_TYPE_INT, {.i64 = 0}, 0, INT_MAX, E },
> +    { "segment_start_number", "set the sequence number of the first
> segment", OFFSET(segment_idx), AV_OPT_TYPE_INT, {.i64 = -1}, -1, INT_MAX, E
> },
>      { "segment_wrap_number", "set the number of wrap before the first
> segment", OFFSET(segment_idx_wrap_nb), AV_OPT_TYPE_INT, {.i64 = 0}, 0,
> INT_MAX, E },
>      { "strftime",          "set filename expansion with strftime at
> segment creation", OFFSET(use_strftime), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0,
> 1, E },
>      { "increment_tc", "increment timecode between each segment",
> OFFSET(increment_tc), AV_OPT_TYPE_BOOL, {.i64 = 0 }, 0, 1, E },
> diff --git a/libavformat/version.h b/libavformat/version.h
> index b00a8b0..645a226 100644
> --- a/libavformat/version.h
> +++ b/libavformat/version.h
> @@ -33,7 +33,7 @@
>  // Also please add any ticket numbers that you believe might be affected
> here
>  #define LIBAVFORMAT_VERSION_MAJOR  57
>  #define LIBAVFORMAT_VERSION_MINOR  73
> -#define LIBAVFORMAT_VERSION_MICRO 100
> +#define LIBAVFORMAT_VERSION_MICRO 101
>
>  #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR,
> \
>                                                 LIBAVFORMAT_VERSION_MINOR,
> \
> --
> 2.6.4
>
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