> On Jul 5, 2022, at 8:07 PM, Gyan Doshi <ffm...@gyani.pro> wrote: > > > > On 2022-07-05 01:20 pm, Zhao Zhili wrote: >> From: Zhao Zhili <zhiliz...@tencent.com> >> >> Streams with all zero sample_delta in 'stts' have all zero dts. >> They have higher chance be chose by mov_find_next_sample(), which >> leads to seek again and again. >> >> For example, GoPro created a 'GoPro SOS' stream: >> Stream #0:4[0x5](eng): Data: none (fdsc / 0x63736466), 13 kb/s (default) >> Metadata: >> creation_time : 2022-06-21T08:49:19.000000Z >> handler_name : GoPro SOS >> >> With 'ffprobe -show_frames http://example.com/gopro.mp4', ffprobe >> blocks until all samples in 'GoPro SOS' stream are consumed first. >> >> Signed-off-by: Zhao Zhili <zhiliz...@tencent.com> >> --- >> libavformat/mov.c | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/libavformat/mov.c b/libavformat/mov.c >> index 88669faa70..2a4eb79f27 100644 >> --- a/libavformat/mov.c >> +++ b/libavformat/mov.c >> @@ -3062,6 +3062,20 @@ static int mov_read_stts(MOVContext *c, AVIOContext >> *pb, MOVAtom atom) >> st->nb_frames= total_sample_count; >> if (duration) >> st->duration= FFMIN(st->duration, duration); >> + >> + // All samples have zero duration. They have higher chance be chose by >> + // mov_find_next_sample, which leads to seek again and again. >> + // >> + // It's AVERROR_INVALIDDATA actually, but such files exist in the wild. >> + // So only mark data stream as discarded for safety. >> + if (!duration && sc->stts_count && >> + st->codecpar->codec_type == AVMEDIA_TYPE_DATA) { >> + av_log(c->fc, AV_LOG_WARNING, >> + "All samples in data stream index:id [%d:%d] have zero >> duration, " >> + "discard the stream\n", >> + st->index, st->id); >> + st->discard = AVDISCARD_ALL; >> + } >> sc->track_end = duration; >> return 0; >> } > > So this will allow audio and video streams to be demuxed, but not data? That > distinction seems arbitrary.
Disable audio/video streams may create regression. It’s unlikely for random and broken data stream. > > Print a warning and assign a duration to each sample. Either 1 or if not > zero/Inf, st->duration/st->nb_frames. Set sample_duration to 1 doesn’t work. Dts still far behind other streams. Set sample_duration st->duration/st->nb_frames works for me, but I prefer current strategy for the following reasons: 1. AVDISCARD_ALL is more close to AVERROR_INVALIDDATA by giving up instead of trying correction and hope it works, which may not, e.g., st->duration is broken, or bad interleave even though we fixed sample_duration. 2. libavformat users can enable the stream and get the original dts/duration, if they want to. > > Regards, > Gyan > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@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-requ...@ffmpeg.org with subject "unsubscribe".
