[vlc-devel] Re: vlc on amd64 -- problems with mencoder's h264 and flash movie files

David Liontooth liontooth at cogweb.net
Mon Mar 13 09:39:30 CET 2006

Merci, Ben --

Benjamin Pracht wrote:

>Le samedi 11 mars 2006 à 23:13 -0800, David Liontooth a écrit :
>>I've been running VLC on amd64 for a while with excellent results, and
>>I've come across two problems that occur on this platform but not on i386.
>>First, h264 files produced with mencoder don't display properly -- the
>>picture is full of blocks to the point of looking milky (I can send pics
>>or make samples available).
>>Second, flv (flash movie) files produced with mencoder don't even open
>>(debug below).
>VLC doesn't have any native support for flv AFAIK. We have a ffmpeg
>demuxer that could take care of it, but we certainly wouldn't be able
>to decode the video data inside anyway (unless it uses the old vp3 or
>any other open codec. 
VLC on i386 plays flv files flawlessly. Presumably it's using the ffflv
codec from the ffmpeg project, as mplayer does -- mplayer spits out
"Selected video codec: [ffflv] vfm: ffmpeg (FFmpeg Flash video)."  On
i386, VLC plays flv files produced by mencoder on amd64 with perfect
picture and perfect sync.

>Can you check if vlc -l outputs a line looking like
>ffmpeg                ffmpeg demuxer
Yes it does. 

>About your h264 on amd64 issue, it is probable debian and the nightlies
>are compiled against a version of ffmpeg that has issues with playback
>of h264 on amd64. 
If this is the problem, the nightlies should be compiled with a more
recent version of ffmpeg, as recent CVS versions have no issues playing
back flv files.

>Without any debug message, I cannot tell more (and I
>don't think any of the developpers has the hardware to test it).
If it turns out there's an amd64-specific bug that requires hardware, I
would be happy to give someone an account.

>Could you send some more debug info ? 
$ vlc flashtest.flv -v 2
VLC media player 0.8.5-test1 Janus
[00000001] main vlc warning: Unable to get HAL device properties
[00000294] ps demuxer warning: this does not look like an MPEG PS
stream, continuing anyway
[00000294] ps demuxer warning: garbage at input, trying to resync...
[00000350] ps demuxer warning: this does not look like an MPEG PS
stream, continuing anyway

While this isn't terribly informative, it's consistent with your
suggestion that the root of the problem is the version of ffmpeg used in
the nightlies. If that's all there's to it, I'll drop the issue -- it's
not really a problem in either VLC or ffmpeg, just a version issue.

What do you make of VLC's failure to play h264 files encoded with
mencoder on amd64? Not only do these play fine with VLC on i386, but
h264 files encoded with ffmpeg play fine with VLC on amd64.

The problem is quite narrow: encode with mencoder, play on VLC on amd64.
Every other permutation with ffmpeg, platform, and player that I've
tried works fine. This is the bug that mystifies me.


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