It's good to have a unified interface for audio.

But why are all the proprietary codecs present.
(mp3, wmv, aac, h264, ...)

While there is no sign of the FOSS-codec.
Because of the way they are managed, they should deserve some attention from khronos.
Why aren't they included in the first place?
(Could someone answer this question please.)

ogg: http://www.xiph.org/
matroska container: http://www.matroska.org/

Code :
[u]flac container:[/u]
flac codec
[u]ogg container:[/u]
flac codec
vorbis codec
theora codec
speex codec
dirac codec
[u]mkv container[/u]
with already added codec