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 2:19 PM Thierry Foucu <tfoucu@gmail.com> wrote:

>
>
> On Thu, Feb 24, 2022 at 1:50 PM Paul B Mahol <onemda@gmail.com> wrote:
>
>> On Thu, Feb 24, 2022 at 10:36 PM Thierry Foucu <tfoucu@gmail.com> wrote:
>>
>> > 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.
>> >
>>
>> Hmm, so you encode output with resolution change, why not use scale filter
>> as first filter and then no resolution ever change for rest of graph?
>> Adding support for resolution changes to all filters is very time
>> consuming
>> task and I see no real benefit in doing that now.
>>
>
> We do have the scale filter in front of the tpad filter. Here is the
> filter chain we are using
>
> idet=1.04:1.5,yadif=0:-1:1,scale=+528:+864:flags=bicubic,setsar=1,fps=fps=16.601,tpad=stop_mode=clone:stop_duration=2808ms
>
> And it does crash.
>
> Even just fps=fps=16.601,tpad=stop_mode=clone:stop_duration=2808ms
> reproduce the problem.
>

Maybe an option to the tpad filter to decide what should be the output when
the stop_mode == 1 and cache_stop is NULL?
So, in some cases, people may want a color frame, and some other will just
want to exit right away?


>
>
>>
>>
>> >
>> >
>> > > >
>> > > > 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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>> > > > > ffmpeg-cvslog@ffmpeg.org
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>> > > > >
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>> > > > >
>> > > >
>> > > >
>> > > > --
>> > > >
>> > > > Thierry Foucu
>> > > > _______________________________________________
>> > > > ffmpeg-devel mailing list
>> > > > 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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>
>
> --
>
> Thierry Foucu
>


-- 

Thierry Foucu
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