[vorbis] Re: [vorbis-dev] high frequencies response

[Bostjan]

Hi Monty, Frank and others.

The high-frequency-boosting problem has been discussed for quite a while
now. IMHO, it is the most prominent problem of this otherwise
magnificent audio encoder. The problem is easily noticeable in the known
applaud test sample at

http://lame.sourceforge.net/download/samples/applaud.wav

This is what led me to ask for advice on 2002-02-12 when I posted the
message "[vorbis] APPLAUD.WAV  problems".

Some time has passed from then and RC3 has been replaced with 1.0. The
artefact is now less pronounced but still noticeable. I am realizing
that the problem is not so easy to solve.

Monty wrote:
/////////////////////////
I've been assuming for some time that this phenomenon (high
frequencies seeming amplified) has been a combination of two things:
....
Both of these contribute to the impression of boosted highs.  Rather
1) gives the impression, but 2) can actually result in a few dB of
boost.  This is why it seems like at -q 6 the problem mostly
disappears, when lossy stereo is finally completely switched off.
\\\\\\\\\\\\\\\\\\\\\\\\\

Perhaps the short-term solution would be to implement the
lossless-stereo-encoding-switch in the next official release. This would
make content those of us, who like more the sample that

-> sounds closer to the ORIGINAL
   but worse as STAND-ALONE 

than the one that

-> sounds better as STAND-ALONE
   but is different from the ORIGINAL,

which is what Monty prefers if I understood correctly. I appreciate your
effort in makinf oggenc easy to use, but this switch would greatly
increase its usefullness for some critical stereo samples.

Thank you for your effort Monty and colleagues.

Regards,
Bostjan

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