[FFmpeg-devel] [PATCH] H.264: fix decoding of plain still images (broken since revision 14289)

Michael Niedermayer michaelni
Wed Jan 7 19:07:54 CET 2009

On Wed, Jan 07, 2009 at 06:22:58PM +0100, Reimar D?ffinger wrote:
> On Wed, Jan 07, 2009 at 04:06:12PM +0100, Michael Niedermayer wrote:
> > On Wed, Jan 07, 2009 at 10:54:28AM +0100, Reimar D?ffinger wrote:
> > > and if I understand right it is not even split into a separate frame by
> > > AVParser.
> > 
> > the parser does split it, mplayer isnt using the parser IIRC
> This is not about MPlayer, ffdshow was having issues.

well i dont know what ffdshow is doing, AFAIK they use libmpeg2 for mpeg1/2
and am not aware of what issues you speak of exactly.

> I only concluded that AVParser would not split it because the
> corresponding hunk from here:
> http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2006-November/019538.html
> was not applied - at least I guessed that the "if(state ==
> SEQ_END_CODE)" was for that purpose, I did not check that carefully.

well if you look at svn, you will see that there is a check for SEQ_END_CODE
in the parser. I assumed that this code works, i did not test it.
If you think the code does nt work ill surely look at it, are you trying
to say that the code does not work?

> Anyway I just wanted to make sure that it does not end up making the
> behaviour of MPEG2 and H.264 any more different than necessary.

Well, iam unsure how h.264 can handle still images at all without the
user applications action. The patch here as i said might not work but
then it also shouldnt harm. The mpeg2 method should work with a single
frame delay but will also not work with more than 1 frame delay.

But then i really would love to see a spec that describes still images
in h264 such spec likely also explains how to handle them correctly.
Am i guessing correctly that such spec is not publically available?

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Dictatorship naturally arises out of democracy, and the most aggravated
form of tyranny and slavery out of the most extreme liberty. -- Plato
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