[vlc] Re: [Partial patch] vlc and xvid encoding

[Bernhard Rosenkraenzer]

On Sunday 28 November 2004 10:45, Sigmund Augdal wrote:
> VLC's avi muxer is broken, and nobody wants to fix it, since avi apperantly
> is a horrible format.

It is -- unfortunately it's also the most common one out there.

> Most probably. If you can write a encoder module for vlc, you can probably
> search through the ogg muxer for the fourcc as well?

Sure, already done in my local tree (will post the patch when I've verified it 
actually works).
I've found a new problem though -- at least if my reading of the code is 
correct, even if xvid support is present in ffmpeg it's never actually used 
by vlc.

vlc determines which ffmpeg encoder to use by running GetFfmpegCodec 
[modules/codec/ffmpeg/encoder.c:172]; GetFfmpegCodec gets the codec ID from 
codecs_table[] (modules/codec/ffmpeg/ffmpeg.c:401), which in turn hardcodes 
CODEC_ID_MPEG4 for the xvid fourcc.

Changing this to CODEC_ID_XVID would break systems where ffmpeg is compiled 
without xvid support; also it would use CODEC_ID_XVID for decoding rather 
than just encoding (and ffmpeg generally seems to give better results as a 
decoder).
Unless I'm overlooking something, the only clean fix would be adding a 
configure check for xvid support in ffmpeg (which would break for 
crosscompiles because it can't be found out without AC_TRY_RUN) and splitting 
i_codec in codecs_table[] into i_codec_encoder and i_codec_decoder...
Or better yet, get the ffmpeg guys to add an 
avcodec_find_{en,de}coder_by_fourcc.

> Probably a real easy 
> fix. If this makes your xvid module useable I guess we should consider
> including it as a light weight alternative to ffmpeg.

Doesn't work ATM even with the fourcc additions, but I tend to think I'm just 
overlooking something small.

LLaP
bero

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