[vorbis] Uncoupled mode?

Moritz Grimm
2002-07-12T14:48:36Z

Pádár Attila wrote:
> Can we use uncoupled encoding in the 1.0?
[...]
> Because I think so it's better if I don't
> use any kind of channel coupling (lossless
> neither) on high bitrates (>300 kbit).

Not using any coupling would be a waste of space - it makes no sense to
store mono parts in a stereo tune twice, i.e. there's only one of two
channels stored completely plus the difference to the second channel.
Doing that without using lossy techniques to reduce stereo information
happens in CVS > -q 6, that's 192 kbps nominal (to answer your question,
what you want already happens). Afaik, uncoupled modes get only used on
Vorbis streams with more than two channels, or mono songs, of course.
(Guessing that, I believe I read something like that months ago ...
might be outdated information.)

I heard it's possible to force the encoder to use lossless coupling,
maybe even uncoupled modes (brrrr, i really hope it doesn't allow that
;( ), on lower quality settings, instead of the favored "smart stereo"
using that vorbis_encode_ctl() function or undocumented oggenc
parameters. (I'm not sure about that either, I didn't look at the code
yet to figure out the undocumented options of oggenc.)

That's not a good idea, though, and should be used for testing only.

Moritz

P.S.: Grml, Monty was faster :) Anyways, for heaven's sake, *send*.