[EMAIL PROTECTED] schrieb am Die, 05 Sep 2000:
> Howdy Gabriel,
>
> > Am I the only one wich doesn't understand what Frank is telling?
> > Can anyone explain a little?
>
> You are not alone. Once I get past his aggressively authoritative posting
> style (which is a major disincentive to understanding for me), I find I
> understand about half of what Frank posts. (Some of which seems actually
> both relevant _and_ useful.*) This is not one of those postings.
>
> I assume he has some theoretical basis for wanting to correlate
> differentiated signals (rather than raw signals), and that this is somehow
> relevant to LAME (I haven't grepped through the source, but I remember
> hearing some discussion of a correlator being used for joint switching?),
> but, since he mentions neither before reeling off a long tabulation of
> statistics, it all seems pretty out of the blue to me, too.
>
> Perhaps a better question would be: Does anyone actually understand what
> Frank is _saying_ (not tell), and would they care to enlighten the rest of
> us?
>
> Alex
Alex, if you remember Frank's post about DC offsets, there he attached
a little C program to calculate AC/DC offsets as well as a correlation
between left and right channels. (was around 00/08/05)
I plugged into LAME that correlation test for a single frame.
If you define RH_VALIDATE_MS at compile time this code gets active.
Actually the decision whether to use L/R or M/S coding is based
on masking relations. But sometimes LAME switches to M/S coding
where L/R coding would be using fewer bits. The extra code you
can enable with above defined will try to get a rough estimation
on the correlation of left and right channels and will consider
the perceptual entropy to check if it would be better not to switch
to M/S coding.
Ciao Robert
PS: www.kraftwerk.de
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