[vorbis] just an idea about quality evaluation

[Giuliano Pochini]

On ven, 2003-01-24 at 16:16, Stoffke wrote:
> Hello 
> 
> I had an idea about judging the quality of ogg vorbis 
> (or any other lossy codec)
> 
> I took a wave-file and encoded it to ogg.
> Then decoded ogg to wav and inverted it's phase. When mixing the original
> wav with the phase-inverted decoded ogg-file, any identic parts of compressed and uncompressed audio should be eliminated. 
> Of course there's always a "rest" of sound because the encoder is not lossless.
> Could this "rest" be an indicator for the quality of the encoder ?

No, because vorbis removes stereo information to compress the file and
thit causes big differences between the original and the compressed
file. Psycoacoustic model used by vorbis is much more complex than a
simple diffecence between two numbers.

Bye.

<p>--- >8 ----
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