[Vorbis-dev] 5.1 surround channel coupling

[Gregory Maxwell]

On 2/28/07, Ralph Giles <giles at xiph.org> wrote:
> I do understand that ambisonic encoding is more efficient, but there
> can definitely be more information in a 5.1 mix than in a 4 channel
> ambisonic mix. In particular, I don't see how you can localize audio
> across the (film) screen as accurately without including some l=2 modes.

Well if the decoder knows it's a transcoded 5.1 stream and does
something like SIRR, then 3 channels should be just fine.

But sure, include second order modes. At the end of the day the
information content should be about the same. Question is does the
ambisonic encoding create a more effective way of exploiting the
redundancy. If the channels are efficiently coupled the number of
channels  will not determine the size ... If ambisonics results in a
more compressible representation unanswered question. But if you
factor in that many ways of exploiting redundancy in the field of 5.1
are patented that tilts the balance.