[vorbis-dev] Why Point-Stereo at 160 kbps ?

Monty
Tue, 30 Jul 2002 13:37:42 -0000

On Tue, Jul 30, 2002 at 04:02:15PM +0200, Sebastian Gesemann
wrote:
>
> Hi there !
>
> I checked Vorbis' performace for mono files at
> approx. 64-80 kbps (it does a good job) and I'm
> wondering why the current OggEnc still uses
> Point-Stereo (>10kHz) for -q4 and -q5

-q4 is currently ~128kbps.  Without point stereo it would be about 180kbps.

> I know, we're usually unable to percieve those
> phase correlations above 10 kHz, But a
> Dolby Prologic Decoder isn't.

Hiding surround encoding in the inadible parts of an audio signal is
so far outside the Vorbis design spec it's hard to know where to
begin.  I'll say this: the whole point of a lossy perceptual encoder
is to lose what you can't hear.

> I think a future version of OggEnc which is able
> to use a user-selectable stereo mode would be graet.

Such a switch will be implemented, promise.

Monty

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