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Possible Poor Performance Of Alt-presets, found a problem sample?
post Sep 23 2002, 23:58
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WinABX developer

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I've just doing some ABX tests with the sample trumpets1.wav, which you can find at http://www.pcabx.com/product/reference/trumpets1.wav

It's a trumpet sound, with no pre-echo issues, just added harshness on some alt-presets.

My results:

--alt-preset standard: 6/6 p= 1.6%, quite easy
--alt-preset standard -Z : 7/7 p= 0.8%, quite easy
--alt-preset extreme : 7/7 p= 0.8%, quite easy
--alt-preset extreme -Z : 12/14 p= 0.6%, seems more difficult, or I'm more tired
--alt-preset insane: 3 trials, total 20/32 p=14%, quite difficult, I think I can ABX it on optimum conditions, but I can't prove it right now rolleyes.gif . Edit: not so sure I can ABX it...

So, seems that the VBR alt-presets have more room for tuning?
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post Sep 24 2002, 17:36
Post #2

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I did some studies on the awe32.wav clip with AAC encoder. It has the same problem as with fatboy.wav. The attacks are too closely spaced and somehow, temporal processing is not sufficient to compensate for pre-echo.. As a result it is necessary to switch to short-block completely just as Ivan has pointed out for fatboy.wav (search for AAC forum about QTime MPEG4 encoder)..

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