[FFmpeg-devel] [PATCH] libavcodec/h263dec.c: Duplicate the last decoded frame when xvid marks the packet as skipped.

Thierry Foucu tfoucu at gmail.com
Thu Oct 26 02:41:36 EEST 2017


On Wed, Oct 25, 2017 at 4:36 PM, Michael Niedermayer <michael at niedermayer.cc
> wrote:

> On Wed, Oct 25, 2017 at 04:21:28PM -0700, Thierry Foucu wrote:
> > On Wed, Oct 25, 2017 at 2:43 PM, Carl Eugen Hoyos <ceffmpeg at gmail.com>
> > wrote:
> >
> > > 2017-10-25 20:38 GMT+02:00 Thierry Foucu <tfoucu at gmail.com>:
> > >
> > > > Without the patch, the decoder will return only 29 frames
> > >
> > > Isn't that the correct and expected output?
> > >
> >
> > Not sure what you mean by correct.
> > There are only 29 VOP encoded, and over 1900 N_VOP packets.
> > If you just demux the sample file, you will get 1947 packets
> >
> > I used the Xvid decoder from
> > http://svn.xvid.org/trunk/xvidcore/examples/xvid_decraw.c
> >
> > to decode the same file, and their decoder outputted 1947 frames.
> >
> >
> > >
> > > If you need cfr, you can request it.
> > >
> >
> > true, but this works as long as you have 2 frames and you can cfr between
> > them. But what if you have the last X second of the file with only N_VOP
> > frames
> > In this case, the decoder will not output frames and the transcoded file
> > will be shorter by X second
>
> the decoder could output a final frame during decoder flush to make
> sure the last NVOPs duration is not lost
>

Oh, that's sound interesting. Let me see if i understand the code enough to
do exactly this.

>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
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> governed by those who are dumber. -- Plato
>
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