On Sat, Nov 28, 2020 at 8:08 PM <mindm...@gmail.com> wrote: > From: Mark Reid <mindm...@gmail.com> > > The current behaviour ends up squaring the avg_frame_rate if the conter > mode flag is set. > This messes up the timecode calculation, and looks to me as a regression > that > seems to have been introduced 428b4aac. > > The new behaviour is use the "Number of frames" field for avg_frame_rate > from the timecode atom as describe here: > > https://developer.apple.com/library/archive/documentation/QuickTime/QTFF/QTFFChap3/qtff3.html#//apple_ref/doc/uid/TP40000939-CH205-69831 > > Number of frames > An 8-bit integer that contains the number of frames per second for the > timecode format. > If the time is a counter, this is the number of frames for each > counter tick. > > Here is a sample mov file with the counter flag set > https://www.dropbox.com/s/5l4fucb9lhq523s/timecode_counter_mode.mov > > before the patch ffmpeg will report the timecode as: > 00:37:11:97 and warns that the timecode framerate is 576000000/1002001 > > after patch: > 14:50:55:02 > > --- > libavformat/mov.c | 17 +++++------------ > 1 file changed, 5 insertions(+), 12 deletions(-) > > diff --git a/libavformat/mov.c b/libavformat/mov.c > index 2b90e31170..76c1ceb82a 100644 > --- a/libavformat/mov.c > +++ b/libavformat/mov.c > @@ -2336,24 +2336,17 @@ static int mov_parse_stsd_data(MOVContext *c, > AVIOContext *pb, > tmcd_ctx->tmcd_flags = val; > st->avg_frame_rate.num = AV_RB32(st->codecpar->extradata + > 8); /* timescale */ > st->avg_frame_rate.den = AV_RB32(st->codecpar->extradata + > 12); /* frameDuration */ > -#if FF_API_LAVF_AVCTX > -FF_DISABLE_DEPRECATION_WARNINGS > - st->codec->time_base = av_inv_q(st->avg_frame_rate); > -FF_ENABLE_DEPRECATION_WARNINGS > -#endif > + > /* adjust for per frame dur in counter mode */ > if (tmcd_ctx->tmcd_flags & 0x0008) { > - int timescale = AV_RB32(st->codecpar->extradata + 8); > - int framedur = AV_RB32(st->codecpar->extradata + 12); > - st->avg_frame_rate.num *= timescale; > - st->avg_frame_rate.den *= framedur; > + st->avg_frame_rate.num = st->codecpar->extradata[16] /* > fps, frames per counter tick in counter mode */; > + st->avg_frame_rate.den = 1; > + } > #if FF_API_LAVF_AVCTX > FF_DISABLE_DEPRECATION_WARNINGS > - st->codec->time_base.den *= timescale; > - st->codec->time_base.num *= framedur; > + st->codec->time_base = av_inv_q(st->avg_frame_rate); > FF_ENABLE_DEPRECATION_WARNINGS > #endif > - } > if (size > 30) { > uint32_t len = AV_RB32(st->codecpar->extradata + 18); /* > name atom length */ > uint32_t format = AV_RB32(st->codecpar->extradata + 22); > -- > 2.29.2 > > ping _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
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