[xiph-rtp] Suggested changes to the Vorbis SDP attributes

Ralph Giles giles at xiph.org
Sat Oct 23 15:34:39 PDT 2004


On Sat, Oct 23, 2004 at 10:37:54PM +0200, Tor-Einar Jarnbjo wrote:

> extension mechanism for the bandwidth modifier and defien X-NOM, X-MIN 
> and X-MAX to be used for the corresponding Vorbis header entries. The 
> bandwidth value is given in kbps and not in bps as in the Vorbis header.

That makes sense, thanks. Especially since these fields are pretty advisory
in the vorbis format itself.

> What do you mean with "mapping"? Channel 0 is left and channel 1 is 
> right? That mapping is irrellevant at the point of parsing the session 
> description and must be handled somehow by the codec.It might be used by 
> a client though to chose between e.g. a 1, 2 or 5 channel stream 
> depending on the client's capabilites.

I mean if the SDP says the stream has 6 channels, does the spec say
anything about which of those channels is which (left, right, front,
back, center, LFE, ambisonic, etc)? There's a mapping in the vorbis
spec; I just wondered if we needed to do any translation to the RTP
payload.

 -r


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