How to required packages with variants

[Jean-Michel Pouré]

On Wed, 2009-01-28 at 11:43 -0800, David Evans wrote:
> My understanding is the without the x264 option, ffmpeg includes its
> own 
> codec (h264) and
> with it an additional libx264 codec is included.  So I guess it
> depends 
> on whether the libx264
> codec is being called by name and what the relative facilities of
> each 
> are -- you probably
> know more about this than I do though.
> 

FFmpeg includes codecs for reading and writing. Read and write support
is not the same.

=> In the case of H264, FFMpeg can read natively but needs x264 to write
to
H264.

=> The same happens for mp3 : FFmpeg can read natively and not write.
Therefore FFmpeg needs liblame. 

I had a look at the sox package that MLT uses for effect and sound
conversion. Well, I was surprised to see several variants:

Variants: ffmpeg flac lame mad universal vorbis 

Sox is the swizz army knife for converting files. What is the interest
of Sox for users if people cannot read/write in vorbis or flac or even
use FFmpeg with it. This could lead to problems in softwares like MLT or
Kdenlive.

Kind regards,
JM