[vorbis-dev] Spectral band replication

[Mike Coleman]

Gregory Maxwell <greg at linuxpower.cx> writes:
> Actually, although not scientifically tested (just my experience), perceptual
> codecs work *BETTER* with high-end equipment. The listening tests that form
> their basics are done on good equipment, and they compress based on what they
> think the listeners ears will be receiving (masking, etc). 
> 
> For an example of this, play a .wav and a .mp3 in XMMS and then make the EQ
> settings funky (simulating bad equipment), listen to the difference of the
> difference. A transparent mp3 is no longer transparent on the funkey EQ
> settings because you have thrown off the masking calculations, MP3s subband
> coarseness makes this more obvious, but the effect should exist for all
> perceptual codecs..
> 
> Unfortunately, since the precise nature of the bad as it varies from place to
> place, you can't test or train for it.. Your best hope is to design for a
> perfect sound system and hope that any users who actually care about quality
> will create a good sound system.

This is an interesting observation.  So for certain sorts of crappy sound
setups, or for listeners with certain sorts of hearing loss, your compression
will potentially sound crappy on playback.  Hmm.


-- 
Mike Coleman, mkc at mathdogs.com
  http://www.mathdogs.com -- problem solving, expert software development

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