[xiph-rtp] Theora RTP payload format

[Michael Smith]

> Our concern with defining profiles, like the 'VP3' bit I suggested has
> always been encouraging inoperable implementations that only support
> that profile. "profiles are useless" has been a common lesson of many
> specification designs. They make committee decisions easier, but then
> end you either implement the de facto standard or you don't. Those are
> the main reasons I remain unconvinced.

A side note here:

Though the profile-less codebook based mechanism has served vorbis
well so far, we're now seriously considering introducing some sort of
profile mechanism. The reasoning behind this is that the existing
embedded implementations _already_ don't support the full
specification (they can't really - full vorbis can require a lot of
memory in pathelogical cases, and even normal streams can commonly
exceed what the more limited flash-based devices can manage), but
there's some impetus to standardise the subset that they do support.
Without that, the "de-facto standard" is actually different between
different manufacturers, and we have no way to label 'vorbis
compliant'.

Mike