Use of PCM and Vorbis in the Mobile Profile of SMIL 3.0

Section "18.4.8 Required MIME Types", part of the SMIL 3.0 Mobile
Profile, indicates:
[[
  * audio/basic [MIME-2]
      * Ogg Vorbis [VORBIS]
      * image/png [PNG-MIME], [PNG-REC]
  * image/jpeg [MIME-2], [JFIF]
]]
http://www.w3.org/TR/2007/WD-SMIL3-20070713/smil-mobile-profile.html#q14

Requiring the use of PCM and Vorbis in the mobile environment might be
difficult for two reasons:
- it *seems* that Vorbis requires more CPU to be decoded than a format
like AAC, thus rendering its use in a mobile environment more
problematic.
- 3GPP and 3GPP2 already adopted AAC as their audio codec (+ some AMR
speech codecs). It's hard to imagine the mobile industry willing to
switch to a different format now.

So, while I certainly don't want to suggest that the Mobile profile must
require support for AAC, I wonder if the current proposal will be
welcome by the Mobile industry...

Regards,

Philippe

PS: I'm copying Ivo Emanuel Gonçalves and Dominique Hazael-Massieux
since they might have some input or comments.