[vorbis] just an idea about quality evaluation

[Ross Vandegrift]

On Fri, Jan 24, 2003 at 05:16:10PM +0100, Stoffke wrote:
> Hello 
> 
> I had an idea about judging the quality of ogg vorbis 
> (or any other lossy codec)

<snip>

Others have commented on why this is a bad test for perceptual lossless
testing, *however*, this test does have it's place.

If you're not comparing how the codecs sound (which most people are
interested in), but what data they throw away, this test is very
valuable.

I did a linguistics research problem on lossy encodings at low bitrates
with mp3.  We used this technique to compare what energy was lost, and
if that loss was acceptable for linguists who wanted to do phonetics
research with lossy compression.

Spectral comparisons are also very useful in doing this kind of "what am
I actually throwing out" comparisons.  Note though, that these
comparisons really don't tell you anything about how something sounds.


-- 
Ross Vandegrift
ross at willow.seitz.com

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