[whatwg] Give guidance about RFC 4281 codecs parameter

[Silvia Pfeiffer]

Xiph has taken on board the many comments received over the last years
wrt MIME types and file extensions and is working on this more
appropriate I-D for MIME types cited by Ivo.

Here is what effect it has on the WHAT-WG spec:

The spec:
> Theora video and Vorbis audio in Ogg container
>    <source src="video.ogg" type="application/ogg; codecs="theora, vorbis"">

The new way:
Theora video and Vorbis audio in Ogg container
    <source src="video.ogv" type="video/ogg; codecs="theora, vorbis"">

The spec:
> Theora video and Speex audio in Ogg container
>    <source src="video.ogg" type="application/ogg; codecs="theora, speex"">

The new way:
Theora video and Speex audio in Ogg container
   <source src="video.ogv" type="video/ogg; codecs="theora, speex"">

The spec:
> Vorbis audio alone in Ogg container
>    <source src="video.ogg" type="application/ogg; codecs=vorbis">

The new way:
Vorbis audio alone in Ogg container
   <source src="audio.ogg" type="audio/ogg; codecs=vorbis">
  or
   <source src="audio.oga" type="audio/ogg; codecs=vorbis"> (preferred)


Also further examples are:

* Speex audio alone in Ogg container
   <source src="audio.spx" type="audio/ogg; codecs=speex">
  or
   <source src="audio.oga" type="audio/ogg; codecs=speex"> (preferred)

* Flac audio alone in Ogg container
   <source src="audio.oga" type="audio/ogg; codecs=flac">


Regards,
Silvia.


On 10/14/07, Ivo Emanuel Gonçalves <justivo at gmail.com> wrote:
> 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
>