[opus] ambisonics formats and channel mappings

[Marc Lavallee]

On Tue, 31 May 2016 09:41:37 -0700
Michael Graczyk <mgraczyk at google.com> wrote:

> UHJ is an interesting way to preserve compatibility with non-ambisonic
> playback systems. However, I have not seen it generalized to higher
> orders. I expect that its popularity will decrease as HOA becomes more
> and more common. If UHJ becomes popular in the future, we could
> specify rules for encapsulating UHJ in Ogg. I believe that should use
> a different channel mapping for simplicity.

As UHJ only have 2 channels, and is directly stereo and mono compatible,
it would nice to have it identified as UHJ in the metadata. There's no
need for decoding at this point; an external decoder could take care of
it for speaker arrays or binaural listening.

--
Marc