Re: [FFmpeg-devel] [FFmpeg-cvslog] avfilter/vf_tpad: if there is no frame to clone return early

[Thierry Foucu <tfoucu@gmail.com>]

On Thu, Feb 24, 2022 at 1:28 PM Paul B Mahol <onemda@gmail.com> wrote:

> On Thu, Feb 24, 2022 at 10:12 PM Thierry Foucu <tfoucu@gmail.com> wrote:
>
> > On Thu, Feb 24, 2022 at 12:30 PM Paul B Mahol <git@videolan.org> wrote:
> >
> > > ffmpeg | branch: master | Paul B Mahol <onemda@gmail.com> | Thu Feb 24
> > > 20:32:41 2022 +0100| [3715f2f8643695940582ce040b7a052cccfb9db2] |
> > > committer: Paul B Mahol
> > >
> > > avfilter/vf_tpad: if there is no frame to clone return early
> > >
> > > >
> > >
> >
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=3715f2f8643695940582ce040b7a052cccfb9db2
> > > ---
> > >
> > >  libavfilter/vf_tpad.c | 5 +++++
> > >  1 file changed, 5 insertions(+)
> > >
> > > diff --git a/libavfilter/vf_tpad.c b/libavfilter/vf_tpad.c
> > > index e5acece1e4..120dbcb4d3 100644
> > > --- a/libavfilter/vf_tpad.c
> > > +++ b/libavfilter/vf_tpad.c
> > > @@ -148,6 +148,11 @@ static int activate(AVFilterContext *ctx)
> > >                                frame->data, frame->linesize,
> > >                                0, 0, frame->width, frame->height);
> > >          } else if (s->stop_mode == 1) {
> > > +            if (!s->cache_stop) {
> > > +                s->pad_stop = 0;
> > > +                ff_outlink_set_status(outlink, AVERROR_EOF, s->pts);
> > > +                return 0;
> > > +            }
> > >              frame = av_frame_clone(s->cache_stop);
> > >              if (!frame)
> > >                  return AVERROR(ENOMEM);
> > >
> > >
> > The problem with this solution is that the tpad will then not do what we
> > are expecting, which is padding video track, and the output file will not
> > have the desired duration.
> > Will it not be better to just output black frame (aka stop_mode == 0) ,
> > something like that?
> >
>
> I doubt that, clone is clone, there is no point in padding stream that have
> no frames at all.
>
>
>
The sample I forwarded to JB has video frames. The problem was that there
was a re-init of the filter chain after a resolution change and after the
re-init, there were no frames but got frames before the re-init.
I will understand for a media file which has NEVER received a video frame
and in this case, this is the correct solution.



> >
> > iff --git a/libavfilter/vf_tpad.c b/libavfilter/vf_tpad.c
> > index e5acece1e4..5e4062e9f2 100644
> > --- a/libavfilter/vf_tpad.c
> > +++ b/libavfilter/vf_tpad.c
> > @@ -140,7 +140,7 @@ static int activate(AVFilterContext *ctx)
> >              ff_outlink_set_status(outlink, AVERROR_EOF, s->pts);
> >              return 0;
> >          }
> > -        if (s->stop_mode == 0) {
> > +        if (s->stop_mode == 0 || !s->cache_stop) {
> >              frame = ff_get_video_buffer(outlink, outlink->w,
> outlink->h);
> >              if (!frame)
> >                  return AVERROR(ENOMEM);
> >
> >
> >
> >
> > > _______________________________________________
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> > >
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> > >
> >
> >
> > --
> >
> > Thierry Foucu
> > _______________________________________________
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> > ffmpeg-devel@ffmpeg.org
> > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
> >
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> >
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-- 

Thierry Foucu
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