[vorbis] channel coupling (was: Re: mp3PRO encoder/decoder demo available)

Moritz Grimm gtgbr at gmx.net
Fri Jun 15 01:41:19 PDT 2001



Hi Monty,

Monty wrote:
> "It depends".  Vorbis will be able to do coupling such that joint
> stereo is exactly equivalent to L/R (reduction is in the range of
> 128->100 or so], or apply addiitonal stereo/spatial specific
> psychoacoustics to further reduce bitrate to eliminate inaudible
> elements of the stereo image.  The test encoder I'm working on right

Will users have an option to choose the kind of joint stereo they want
to use lateron? (L/R equivalence vs. psychoacoustics) Personally I'd
love to have both some day, because this would not only provide a
workaround for possible stereo artifacts during the testing stages of
that feature but also make audiophiles happy that pretend to be able to
hear even minor or imaginary "artifacts". (More a psychological aspect
... ;) )

Btw, did you get to have a look at the "bassrumble-bug" i found in
beta4? It was a couple weeks ago when I compiled from CVS and although I
could note an different/higher bitrate that is used for the same music
(including noteable improvement in sound quality), I still was able to
hear that rumbling/knocking sound on the 808 bassdrum (that isn't much
more than a sine wave).

This is not a priority, though ... I don't think that more than a few
people, who don't know what to listen for, will notice it at all.

> I will likely also hack together a tool that adds coupling to existing
> Ogg beta-encoded files without a reencode for extra free savings
> (without a quality penalty).

Yay, that's cool :D

Moritz

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