[Bf-committers] Re: Audio/Video update (Ton Roosendaal)

[Bob Holcomb]

Ton,

Just wanted to answer some of your questions about ffmpeg.  It's a 
multi-platform/architecture library that can be linked statically or 
dynamically.  It also has no hardware dependancies.  I don't know if ffmpeg 
is the best library to use to do this, but it's the best one I've found and 
does seem to be feasible.  However, I'm open to suggestions for other 
libraries.

platforms supported:
Windows, Linux, OS X, SunOS, BeOS, *BSD, QNX

Dependencies:
mp3lame, oggvorbis, faad/faac

It supports quite a few audio/video codecs and containers.  The biggies 
being MP3, Vorbis, AC3, ADPCM, MPEG(1,2,4), H263, DV, Sorenson 1, Real 
Video, Quicktime, and AVI.  It would add some size to blender if it's 
compiled in, but I can't be sure how much bigger.  It will depend on which 
codecs are supported and which are not.  Also, the current AVI and Quicktime 
codecs in blender could be removed helping offset the size increase (and 
cleaning the code a bit). Like the python library, it could be slimmed down 
for the essential codecs and included as a dynamic library.

As far as how it will incorperate into the audio system, I think it will be 
minimal impact.  The current sequencer audio system looks like it will work 
well for mixing and sending the audio data to the encoder.

On the UI side of things, I've created an audio tab and a video tab on the 
render format panel where you can select the encoder to use (ie. MP3, OGG, 
ADPCM, RAW, WAV) and the general properites to set for each (Bitrate, 
Samplerate, FPS).  These values are kept in the G->scene.r data structure.

I hope I answered your questions.  I'm still wading through the blender code 
for where the AVI and Quicktime libraries are called to see where changes 
would need to be made.  If I'm off in left field for any of this, please let 
me know.

Cheers,

Bob

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