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Alt-Preset Standard/Extreme Flaimbait
idfubar
post Apr 30 2003, 18:53
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Forgive me, but a quick question:

Is there any way to determine the difference between alt-preset standard/extreme settings mathematically?

The reason I ask is a CD is limited to a Signal-To-Noise Ratio of 96. Since the limiting factor in encoding is the fidelity of the source, is there someway to determine a "threshold" where using extreme v/s standard can be shown to be advantageous (i.e. shown to have an audible resolution) mathematically?
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2Bdecided
post May 1 2003, 16:20
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ReplayGain developer


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Hi DickD!

I'm still having fun with mp2. At low bitrates (e.g. 128kbps), I prefer toolame -p 2. (or -p 4 - sounds the same to me, but I haven't tested it much).

At high bitrates, I can't hear a difference between the psychoacoustic models. On the version I was testing, -p 3 crashed anyway.

At any reasonable (i.e. hopefully transparent) bitrate, "true" stereo is essential with mp2 - it's joint stereo is quite bad (Intensity stereo only), and rarely transparent.


toolame -b 192 -p 2 -m s
is really good. However, I'm not sure
1) what it's doing above 16kHz (not a lot, I think - but I can't hear that high anyway)
2) if it's coping with harpsichord music very well (I think it maybe isn't - but neither does lame mp3)

Whatever - as you say, it's worth a try. mp2s play fine on my CD-mp3 walkman. CBR only - almost nothing plays mp2 VBR so it's not really worth the effort. sad.gif

If anyone else is thinking of trying it, I'd suggest 192kbps or 256kbps for starters. Lower is audibly worse. Higher hasn't given any improvement for me - but some serious harpsichord ABXing may change that! (Strangely, I have better and more enjoyable things to do! )

Cheers,
David.

P.S. - mathematical comparison of aps vs ape? subtract the original from each encoded file, and measure the remaining noise. What does this tell you? Absolutely nothing useful! Tt doesn't tell you what you can or cannot hear, and the file with the greater (inaudible) noise could even be the one which sounds best. But you asked for a mathematical comparison, and that is one. Now go and listen! wink.gif

This post has been edited by 2Bdecided: May 1 2003, 16:23
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