[FFmpeg-devel] [PATCH] fftools/ffmpeg: Fix EOF pts for libavfilter in send_filter_eof()

Li-Heng Chen lihengc at netflix.com
Sat Sep 17 18:51:01 EEST 2022


Ping. Any comments on the updated patch?

On Tue, Sep 13, 2022 at 9:46 AM Li-Heng Chen <lihengc at netflix.com> wrote:
>
> On Tue, Sep 13, 2022 at 4:40 AM Paul B Mahol <onemda at gmail.com> wrote:
> >
> > On 9/11/22, Li-Heng Chen <lihengc at netflix.com> wrote:
> > > When input is video bitstream (e.g. *.264) with framerate set by -r,
> > > ist->pts could be a nonsense value.
> > >
> > > In libavfilter/vf_fps, the pts value of EOF from above is compared to pts
> > > derived from inlink. The wrong EOF pts may trigger a bug, where ffmpeg keeps
> > > writting the last video frame to the output. This bug can be easily
> > > reproduced by the ffmpeg cmd below (h264 bitstreams in fate-suite can
> > > reproduce this issue):
> > >
> > > ffmpeg -r num_in/den_in -i bitstream -vf fps=num_out/den_out -f rawvideo
> > > out.yuv
> > >
> > > Example: ffmpeg -r 24/1 -i fate-suite/h264/bbc2.sample.h264 -vf fps=24/1 -f
> > > rawvideo out.yuv
> > > Signed-off-by: Li-Heng Chen <lihengc at netflix.com>
> > > ---
> > > fftools/ffmpeg.c | 3 +++
> > > 1 file changed, 3 insertions(+)
> > >
> > > diff --git a/fftools/ffmpeg.c b/fftools/ffmpeg.c
> > > index 0e1477299d..e9a986c95b 100644
> > > --- a/fftools/ffmpeg.c
> > > +++ b/fftools/ffmpeg.c
> > > @@ -2383,6 +2383,9 @@ static int send_filter_eof(InputStream *ist)
> > >     int64_t pts = av_rescale_q_rnd(ist->pts, AV_TIME_BASE_Q,
> > > ist->st->time_base,
> > >                                    AV_ROUND_NEAR_INF |
> > > AV_ROUND_PASS_MINMAX);
> > >
> > > +    if(ist->framerate.num)
> > > +        pts = ist->cfr_next_pts;
> > > +
> >
> > Style is wrong
>
> Style fixed in the attached patch
>
> >
> > >     for (i = 0; i < ist->nb_filters; i++) {
> > >         ret = ifilter_send_eof(ist->filters[i], pts);
> > >         if (ret < 0)
> > > --
> > > 2.32.1 (Apple Git-133)
> > >
> > > _______________________________________________
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