[flac-dev] Define 6.1 and 7.1 channel mappings

[Ralph Giles]

On Fri Sep 21 16:31:21 2012, Stephen F. Booth wrote:

> 6.1:  L R C LFE Ls Rs Cs (MPEG 6.1 A layout)

Having read a bit more:

This matches the WAV (or USB) order if you map Ls (Left Surround?) to
Back Left and Rs (Right surround) to Back Right, instead of mapping them
to Side Left and Side Right as I do.

Practically, there's not much difference in what you call these for 6.1.
If you only have 7 speakers, the signals go to the surround speakers
regardless, and if you have 8, the matrix should send the surround
signals to both side and back speakers.

I chose the 'Side' label over 'Back' based on the suggested ideal
placement diagrammes at sites like crutchfield.com and dolby.com, and
dolby's reference to the 'back surround' speakers in 7.1 as being the
extra ones, not the side speakers.

So the question is, how to choose between mapping surround to "side" and
mapping it to "left". Can you elaborate on "what Apple has done" and why
we should chose the other way?

> 7.1: L R C LFE Ls Rs Rls Rrs (MPEG 7.1 B  layout)

Here I just disagree. This is the same set of labels as in my proposal,
but the order does *not* match WAV order, assuming Ls->left side and
Rls->back left.

 -r