Re: [FFmpeg-devel] [PATCH v2] fftools/ffmpeg: Fix EOF pts for libavfilter in send_filter_eof() - Li-Heng Chen

From: Li-Heng Chen <lihengc@netflix.com>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: Re: [FFmpeg-devel] [PATCH v2] fftools/ffmpeg: Fix EOF pts for libavfilter in send_filter_eof()
Date: Tue, 13 Sep 2022 09:46:31 -0700
Message-ID: <CAC1ZW2joQaubSHpABak3xNrMEYAb+45gptH+y+PVmTE2da1DAA@mail.gmail.com> (raw)
In-Reply-To: <CAPYw7P6R1g=ZMAZ3PFaSn1H6Ueh5tqF+HVZ_BN_x_tk2Hi2P0w@mail.gmail.com>

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On Tue, Sep 13, 2022 at 4:40 AM Paul B Mahol <onemda@gmail.com> wrote:
>
> On 9/11/22, Li-Heng Chen <lihengc@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@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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> > ffmpeg-devel@ffmpeg.org
> > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
> > To unsubscribe, visit link above, or email
> > ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
> >
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