[ogg-dev] OGG Vorbis I

Ralph Giles giles at xiph.org
Thu Apr 26 05:57:34 PDT 2007

On Thu, Apr 26, 2007 at 04:41:50PM +0800, EmilyGao at viatech.com.cn wrote:

> I don't quite understand why vorbis I spec dictates that "Ogg stream
> must be unmultiplexed".
> Ogg can include both audio and video, that means one Ogg stream can both
> have vorbis and theora multiplexed. How vorbis I spec say could not
> allowed?

The last paragraph of Appendix A.1.1 covers that. Decoders are allowed 
to assume an unmultiplexed stream (and libvorbisfile in fact does this)
and be compliant with the spec. The intent is not that you must reject 
multiplexed streams, but that they are out of scope for this particular

The rules for granulepos etc. should still be followed in any 
multiplexed mapping.


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