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NSPsytune's better pre-echo control - myth or reality?
JohnV
post Mar 1 2002, 14:44
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Group: Developer
Posts: 2797
Joined: 22-September 01
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Ok, I'm quite busy, but I'd like to rise this question again..
In my opinion one of the biggest problems of nspsytune is its pre-echo handling still, and especially with long-blocks.
Since the block-switching is not nearly perfect, many times long blocks are used with attacks. Also sometimes transients are just not so sharp, that short blocks would be chosen.

I compared nspsytune lines:
-b320 -h --nspsytune --lowpass 20 --noshort --athtype 2 -Z -X0
-b320 -h --nspsytune --lowpass 20 --noshort --athtype 2
--alt-preset insane --noshort
against gpsycho line:
-b320 -h --lowpass 20 --noshort

The first nspsytune line sets the same properties as gpsycho line (same athtype, same noise shaping type, same noise quality measurement mode). Actually both nspsytune lines handled long-block pre-echo pretty much equally poorly, but first line could be considered "more fair".

some of the test clips I used to demonstrate this:
http://lame.sourceforge.net/download/samples/castanets.wav
http://sivut.koti.soon.fi/julaak/castanets_si02.flac
http://sivut.koti.soon.fi/julaak/blips.flac
http://sivut.koti.soon.fi/julaak/vangelis1.flac

Despite Dibrom's --alt-preset insane tweaks, nspsytune's long-block "problem" still is there.
--alt-preset insane does not solve nspsytune's long-block pre-echo problem...with blips.wav this long-block pre-echo problem is especially noticeable. Of course if block switching works correctly long-block pre-echo handling is not an issue. Of course normally Lame uses short blocks with sharp attacks. --alt-preset insane is still not very good with castanets_si02.wav - Gpsycho was clearly better. Same thing with castanets.wav, vangelis1.wav and quite a few other clips.

In my opinion Naoki should take a look what's going on or at least address this for nspsytune2. I've often thought, that nspsytune is not producing better pre-echo handling than gpsycho. This probably means for both long-blocks and short-blocks.

[edit]Edited out the incorrect pictures. EncSpot 1.1beta2's block-switcing view misses short-blocks. I verified this with mp3x-frame analyzer.


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