[vorbis-dev] Stereo mode settings

[Yann Guidon]

hello,

Stephen So wrote:

> Recently a few people did some listening tests at ha.org, comparing 
> standard Vorbis with  lossless coupled and uncoupled Vorbis files and 
> they tend to indicate an improvement when we use uncoupled stereo.  
> Does this sound peculiar?
>
> http://www.hydrogenaudio.org/index.php?showtopic=18359&view=findpost&p=181123 
>
>
> Best regards,
>
> Steve.

<p>my own experiments tends to indicate that stereo coupling is useful only 
at low frequencies
with relatively "pure" sounds.

This gets complicated with echo/reverb chambers that add phase, or with 
stereo
recordings using separate microphones : the phase of the signal is such 
that the "common mode
signal" and the "differential signal" have together as much energy as 
the initial stereo signal.

This is something that should at least be managed by the user, when it 
can't be examined
block per block (which potentially doubles the encoding computing 
requirements).

if anyone has more ideas, i'd be interested to read about his experiments.

YG

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