[FFmpeg-devel] [PATCH] avformat/mov: add option to use tfdt for fragment timestamps.

[Gyan Doshi]

Plan to push tomorrow.

On 2021-05-29 14:34, Gyan Doshi wrote:
> ---
>
> I faced the same issue as the poster in
>
> https://lists.ffmpeg.org/pipermail/ffmpeg-user/2018-March/039038.html
>
> After patch, start_time is correct as well as monotonicity of ts.
>
>   doc/demuxers.texi  | 6 ++++++
>   libavformat/isom.h | 1 +
>   libavformat/mov.c  | 4 +++-
>   3 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/doc/demuxers.texi b/doc/demuxers.texi
> index 13fe17ff4f..38734b577f 100644
> --- a/doc/demuxers.texi
> +++ b/doc/demuxers.texi
> @@ -662,6 +662,12 @@ Set mfra timestamps as PTS
>   Don't use mfra box to set timestamps
>   @end table
>   
> + at item use_tfdt
> +For fragmented input, set fragment's starting timestamp to @code{baseMediaDecodeTime} from the @code{tfdt} box.
> +Default is disabled, which will preferentially use the @code{earliest_presentation_time} from the @code{sidx} box.
> +In either case, the timestamp from the @code{mfra} box will be used if it's available and @code{use_mfra_for} is
> +set to pts or dts.
> +
>   @item export_all
>   Export unrecognized boxes within the @var{udta} box as metadata entries. The first four
>   characters of the box type are set as the key. Default is false.
> diff --git a/libavformat/isom.h b/libavformat/isom.h
> index 5a6d504090..ac1b3f3d56 100644
> --- a/libavformat/isom.h
> +++ b/libavformat/isom.h
> @@ -277,6 +277,7 @@ typedef struct MOVContext {
>       int moov_retry;
>       int use_mfra_for;
>       int has_looked_for_mfra;
> +    int use_tfdt;
>       MOVFragmentIndex frag_index;
>       int atom_depth;
>       unsigned int aax_mode;  ///< 'aax' file has been detected
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index c088c9f515..6c99a67ff5 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -4803,7 +4803,7 @@ static int mov_read_trun(MOVContext *c, AVIOContext *pb, MOVAtom atom)
>               dts = frag_stream_info->first_tfra_pts;
>               av_log(c->fc, AV_LOG_DEBUG, "found mfra time %"PRId64
>                       ", using it for dts\n", pts);
> -        } else if (frag_stream_info->sidx_pts != AV_NOPTS_VALUE) {
> +        } else if (frag_stream_info->sidx_pts != AV_NOPTS_VALUE && !c->use_tfdt) {
>               // FIXME: sidx earliest_presentation_time is *PTS*, s.b.
>               // pts = frag_stream_info->sidx_pts;
>               dts = frag_stream_info->sidx_pts - sc->time_offset;
> @@ -8169,6 +8169,8 @@ static const AVOption mov_options[] = {
>           FLAGS, "use_mfra_for" },
>       {"pts", "pts", 0, AV_OPT_TYPE_CONST, {.i64 = FF_MOV_FLAG_MFRA_PTS}, 0, 0,
>           FLAGS, "use_mfra_for" },
> +    {"use_tfdt", "use tfdt for fragment timestamps", OFFSET(use_tfdt), AV_OPT_TYPE_BOOL, {.i64 = 0},
> +        0, 1, FLAGS},
>       { "export_all", "Export unrecognized metadata entries", OFFSET(export_all),
>           AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, .flags = FLAGS },
>       { "export_xmp", "Export full XMP metadata", OFFSET(export_xmp),