[FFmpeg-devel] [PATCH v3 3/6] ffmpeg: move A/V non-streamcopy initialization to a later point

[Jan Ekström]

On Fri, Oct 16, 2020, 22:47 Michael Niedermayer <michael at niedermayer.cc>
wrote:

> On Fri, Oct 16, 2020 at 04:16:46PM +0300, Jan Ekström wrote:
> > - For video, this means a single initialization point in do_video_out.
> > - For audio we unfortunately need to do it in two places just
> >   before the buffer sink is utilized (if av_buffersink_get_samples
> >   would still work according to its specification after a call to
> >   avfilter_graph_request_oldest was made, we could at least remove
> >   the one in transcode_step).
> >
> > Other adjustments to make things work:
> > - As the AVFrame PTS adjustment to encoder time base needs the encoder
> >   to be initialized, so it is now moved to do_{video,audio}_out,
> >   right after the encoder has been initialized. Due to this,
> >   the additional parameter in do_video_out is removed as it is no
> >   longer necessary.
> > ---
> >  fftools/ffmpeg.c | 112 ++++++++++++++++++++++++++++++++---------------
> >  1 file changed, 77 insertions(+), 35 deletions(-)
>
> This breaks:
>
> ./ffmpeg -ss 30.0 -i ~/tickets/1745/1745-Sample.mkv -f vob -c:a copy  -f
> framecrc -
>

I put the first attempt at a fix for this as a separate commit in this
patch set since it clearly is separate from this change by itself, as well
as if someone would give a better recommendation on how to handle it, it
would be simpler to adjust.

But yes, this specific sample uses more than 128 packets of the codec copy
audio since the resulting seek point is 5+ seconds before the requested
time.

Jan

>