Here is a proposal to help choosing the quantization.
We can use the audition threshold. For each quantization, add the minimal
audition thresholds corresponding to the frequency of each distortion. For a
given over value, the quantization with the lowest sum would be the best.
For the value of this threshold, I suggest using a table giving the minimum
of the audition threshold in the frequency range of each subband. The
following formula gives the human minimal audition threshold of a young
people with very good hearing, f beeing the frequency:
3.64*(f/1000)^(-0.8)-6.5*e^(-0.6)*(f/1000-3.3)^2+10^(-3)*(f/1000)^4
However, I can't compute the table values, as I don't know the frequency
range of each subband, and I didn't find it in the iso doc.
The good points is that this would produce less disturbing distortions, and
it would also produce more constant distortions in frequency, as changes in
distortion are sometimes more disturbing as the distortion itself.
The negative point is that it increases the complexity of the encoding
because the encoding process would need to compute all the possible
quantizations before choosing the right one.
Gabriel Bouvigne - France
[EMAIL PROTECTED]
icq: 12138873
MP3' Tech: www.mp3tech.org
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