[Vorbis] Bit rates, files size

[Hugo van der Merwe]

Makes me curious, could one use the Vorbis model (or even the mp3 model 
then, for that matter) to rate two samples of the same music, as an 
indication of which might be higher quality? (With some threshold set, 
that if the difference is too small, the software would refuse to make a 
recommendation.) I would like somehting that could do this, or maybe 
even just something that can determine whether a raw audio sample has 
been lossily compressed with a certain codec (e.g. mp3 or vorbis) or 
not. The latter should be possible, should it not? If you can measure 
the amount of "inaudible" information in the audio, or ideally, I would 
like Vorbis to compress to smaller sizes at -q8 if it is compressing 
something that has been compressed and decompressed at -q3 than 
something that is the raw original?

Hmm, one too long paragraph.
Hugo

Haxe wrote:

>No, there is absolutely no way to compare the audible quality of two 
>encoders "digitally".
>
>Of course, you can invent some model of how the human ear might "feel" 
>the difference, may it be square differences or anything else, but that 
>doesn't mean that your model even remotely tells the truth about 
>audible quality.
>
>Other mathematical models have been invented before. One model is used 
>in MP3 to get the highest possible "quality" (in terms of that model) 
>with the least possible bits. Vorbis uses another model of measuring 
>"quality". And your sqare difference may be a third model.
>
>But to tell how good a certain model reflects what the ear really feels, 
>there is NO other way than to ask lots of careful listeners in a 
>double-blind test.
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