16 Aug
2009
16 Aug
'09
3:14 p.m.
On Sun, 2009-08-16 at 18:55 +0200, Fons Adriaensen wrote:
On Sun, Aug 16, 2009 at 05:34:47PM +0200, Lennart
Poettering wrote:
What a mess. In a maze of little standard, all different, I think I
will use the simple rule: "left-to-right, then front-to-back, finally
LFE", which seems to match the dolby/AC3/Protools order.
e.g. (LFE in parenthesis)
5.1:
1 2 3
4 5
(6)
7.1:
1 2 3
4 5
6 7
(8)
7.1 wide:
1 2 3 4 5
6 7
(8)
etc. Least it's logical. :) A downside is that just taking the first
two channels doesn't get you stereo, which could suck if you have a 5.1
"multi-buffer" output and a stereo "multi-buffer" input and the
buffers
are just layed out one after another, because if it was LRC you could
connect them directly...
OTOH it's impossible to define a scheme where this is doable for all
combinations, and a proper converter plugin should probably be used in
this case to avoid losing sound anyway.
-dr
P.S. "multi-buffer" is just hypothetical
Look for kCAFChannelBit_xxx resp. SPEAKER_xxx.
The CAF wand WAVEX channel mask is identical, however they used
different names for the same channels. (CAF allows more flexible
definitions via a different chunk, too though, which enables
ambisonics). Given that both MS and Apple seem to follow this rule it
might be a good idea to follow it too.
That would be L R C Lfe Ls Rs.
Protools uses L C R Ls Rs Lfe, which is the 'Dolby'
order as used in the film industry and also for AC3
encoding.
DTS and AAC use C, L, R, Ls, Rs, Lfe.