[Vorbis-dev] 5.1 surround channel coupling

[Ivo Emanuel Gonçalves]

I expected for someone to get in touch with you, and help you get in
the right track.  Most unfortunately, no one did.

I'm not in the know of the technical details on how Vorbis deals with
multi-channel, so all I can suggest if you are still interested, is to
check the vorbis source code, and maybe oggenc's source code as well.

Someone on the Xiph wiki added some interesting links for Ambisonics
stuff.  That may be of use to you as well.

I'll pretty much copy&paste it:

"Resources on Ambisonics

* There is now a set of articles on Wikipedia on Ambisonics [
http://en.wikipedia.org/wiki/Ambisonic ]
* Of particular relevance is the ".amb" specification [
http://www.ambisonicbootlegs.net/Members/mleese/file-format-for-b-format/
] for downloadable B-Format files. There are currently about 75 pieces
available in this format for free download. Most of these are
full-sphere soundfields.
* My website [ http://members.tripod.com/martin_leese/Ambisonic/ ] has
many pages on Ambisonics (including at the bottom links to other
Ambisonic websites)."

Hope this helps,
Ivo Emanuel Gonçalves

On 1/20/07, Qduaty <qduaty at gmail.com> wrote:
> But what about the implementation in Vorbis? As I understand, Vorbis
> supports 2-channel coupling. This implies all multichannel surround models
> must have 2^n channels. There may be two ways to deal with it:
>
> 1. Implement n-dimensional channel coupling
> 2. Treat 5.1 dolby digital content as 4-channel surround + 2 independent
> channels (dialogs + LFE)
>
>  In the second case, we can use two models of quadrophony:
> a) independent coupling for front and back channels, then coupling front
> with back
> L  --  R
>      |
> L' -- R'
>
> b) generate two perpendicular pairs of channels, which gives us possibility
> of mixing down the dialog channel into the Front. Both pairs could be
> coupled independently:
>          Front
> Left     +       Right
>          Back
>
> What you people think about it? ;)