[theora-dev] Changes to Ogg format IETF I-D

Michael Smith msmith at xiph.org
Fri Feb 14 02:35:26 PST 2003

> 2) The main paragraph of trouble (the one that stopped it going forward
> to RFC at the IETF) merged several feedbacks and changed to (Section 4):
> < The bos page contains information to uniquely
> < identify the codec type and MAY contain information to set up the
> < decoding process. The bos page SHOULD also contain information about
> < the encoded media - for example, for audio, it should contain sample
> < rate and number of channels.  By convention, the first bytes of the
> < bos page contain magic data that uniquely identify the required
> < codec.  It is the responsibility of anyone fielding a new codec to
> < make sure it is possible to reliably distinguish his/her codec from
> < all other codecs in use.  There is no fixed way to detect the end of
> < the codec-identifying marker.  The format of the bos page is
> < dependent on the codec and therefore MUST be given in the
> < encapsulation specification of that logical bitstream type.  An
> < example for such a media mapping is "Ogg Vorbis", which provides the
> < name and revision of the Vorbis codec, the audio rate and the audio
> < quality on the Ogg Vorbis bos page.  It is identified by the string
> < "vorbis" at the beginning of the bos.

Paragraph is generally good, but the example at the end is slightly wrong. 
The first packet of a vorbis bitstream starts with the byte 0x01, followed by 
"vorbis" (a total of 7 bytes of identifier).

The rest of this looks really good - thanks a lot for doing all this.


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