[whatwg] Give guidance about RFC 4281 codecs parameter

[Ivo Emanuel Gonçalves]

On 10/13/07, Ian Hickson <ian at hixie.ch> wrote:
> > Recent discussion at Xiph around http://www.ietf.org/rfc/rfc4281
> > suggests the use of the following parameters:
> >
> > # application/ogg; codecs="theora, vorbis"   for Ogg Theora/Vorbis files
> > # application/ogg; codecs="theora, speex"   for Ogg Theora/Speex files
> > # application/ogg; codecs="vorbis"                 for Ogg Vorbis files
> >
> > and also use the disposition parameter:
> >
> > # application/ogg; disposition=moving-image; codecs="theora, vorbis"
> > # application/ogg; disposition=sound; codecs="speex"
> >
> > Skeleton and the use of these MIME parameters should make things clear
> > for the application developers.

This information is not accurate anymore according to the Internet
Draft[1] Xiph is working on to help solve the mess.

video/ogg should be used for any kind of visual material inside Ogg.
audio/ogg should be used for audio material in Ogg.

These media types have a SHOULD requirement for Skeleton to help
interoperability.  There is one exception in audio/ogg for that
requirement, which is related to serving Vorbis- or Speex-only files
that need backward compatibility.  This separation is explained in the
I-D.

application/ogg is to be used in special cases where video/ogg or
audio/ogg are not recommended.  Imagine scientific applications that
require dozens of multiplexed signals.  Content served under
application/ogg MUST have a Skeleton logical stream.

-Ivo

[1] https://trac.xiph.org/browser/experimental/ivo/drafts/draft-xiph-rfc3534bis.txt