[FFmpeg-devel] wmv3: poor decoding of some files

[Kostya]

On Wed, Jun 27, 2007 at 03:07:03PM +0200, Nicolas George wrote:
> Hi.
> 
> Reimar D?ffinger tells me it is not a known issue, so I report it fully
> here:
> 
> The decoding of some WMV3 files, and in particular the videos published by
> the French TV "Canal+" is quite poor: some frames become garbled (as if it
> decoded a P-frame without the corresponding I-frame), and the whole is much
> too pink.
> 
> Such a video can be found at:
> mms://vipmms.canalplus.fr/canalplus/guignols_070622_a.wmv
> And there is a copy at:
> ftp://quatramaran.ens.fr/pub/cigaes/guignols-20070622.wmv

Thanks for the sample, it's problematic for me to get it via mms://

> The full output of ffmpeg is:
> 
> <------------------------------ cut here ------------------------------>
> 
> $ ffmpeg -i /data/big/guignols/guignols-20070622.wmv
> FFmpeg version SVN-r9446, Copyright (c) 2000-2007 Fabrice Bellard, et al.
>   configuration: --prefix=/opt/ffmpeg-20070627 --extra-cflags=-I/usr/local/include --extra-ldflags=-L/usr/local/lib --enable-gpl --enable-libgsm --enable-libmp3lame --enable-libogg --enable-libvorbis --enable-libtheora --enable-libfaad --enable-libfaac --enable-libxvid --enable-libx264 --enable-liba52 --enable-x11grab --enable-swscaler --enable-pp --enable-shared --enable-pthreads
>   libavutil version: 49.4.1
>   libavcodec version: 51.40.4
>   libavformat version: 51.12.1
>   built on Jun 27 2007 14:51:59, gcc: 4.1.2 20061115 (prerelease) (Debian 4.1.1-21)
> [wmv3 @ 0x2ba4df1d9b70]WMV3 Complex Profile is not fully supported
                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> [wmv3 @ 0x2ba4df1d9b70]1 for reserved RES_X8 is forbidden
> [wmv3 @ 0x2ba4df1d9b70]0 for reserved RES_FASTTX is forbidden
> [wmv3 @ 0x2ba4df1d9b70]Read 16 bits in overflow

As you can see from these messages it's WMV3 CP(complex profile). There is no documentation
on it and the current implementation is mostly guesswork that sometimes work.

RES_X8 means you will have some missing keyframes and RES_FASTTX is signalling that
colors will be deviating.

Maybe after RV40 I'll have time to look at it and I'm not sure somebody else will
improve it (Reimar, you showed not sufficiently strong refusal to work on X8 so you are
an ideal candidate *g* ).

[...]
> I must add that mplayer with the win32 proprietary codec read it correctly.

Exactly
 
> Regards,
> 
> -- 
>   Nicolas George