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"alt-preset standard -Y" VS "preset medium"
ursus
post Jan 18 2003, 05:17
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I'm using LAME (3.90.2) and "--alt-preset standard -Y" currently,
after much experimentation with the -V setting, lowpass, trying
--r3mix, etc. Overall I'm impressed with the high quality retained
with "-Y" compared to plain APS, despite the average bitrate
dropping from 220+ to a more reasonable ~180 ... I understand
some people (younger folks? :) with exceptional hearing might
object to some of the HF detail lost with "-Y" but I certainly can
barely (if at all) distinguish between APS / APS-Y.

I did try using the "fast" VBR mode (vbr-mtrh) via "--alt-preset
fast standard -Y" but due to some quirk of the vbr-mtrh mode,
the bitrate distribution (as viewed in EncSpot) shows a wierd
inverted slope from 192 and up (e.g. 320 > 255 > 224 bars).
Unfortunate, as vbr-mtrh is so much faster than vbr-old ...

I decided to try out the new "preset medium" with LAME 3.93.1,
but after just two encodes I've decided this sounds really bad,
muddy, background instruments sound like they are redubbed;
perhaps the average bitrate is just too low (usually <160)???
I thought, with similar optimizations as --alt-preset standard,
the new --preset medium should sound BETTER than APS-Y, but
so far this is not so.

Is "--alt-preset standard -Y" currently the best compromise?
Also, why is the bitrate distribution so sharply peaked with
the "-Y" setting, compared to "--r3mix" or "-V3 -b96 -h -mj"?
Maybe I am just ignorant in saying this, but shouldn't bitrate
distribution be falloff more smoothly on either side of the avg
bitrate peak?

I've thought of trying MPC or Ogg but the compatibility issues
keep getting in the way (maybe when iRiver provides Ogg
playback for the SlimX I'll reconsider).
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mithrandir
post Jan 18 2003, 05:29
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QUOTE
I decided to try out the new "preset medium" with LAME 3.93.1,
but after just two encodes I've decided this sounds really bad,
muddy, background instruments sound like they are redubbed;
perhaps the average bitrate is just too low (usually <160)???
I thought, with similar optimizations as --alt-preset standard,
the new --preset medium should sound BETTER than APS-Y, but
so far this is not so.

I presume that is Gabriel's medium preset. Try it again with an additional switch: -b 128, so your commandline looks like:

lame --alt-preset medium -b 128

If you are looking for quality I have found that you need to limit the VBR modes to 128kbps minimum. Much of the noise and general annoyances seem to come from VBR dipping too far down in the bitrate.

Also, the "preset medium" is simply a hardcoded commandline. --alt-preset standard -Y generally sounds much better because it utilizes algorithms that are not accessible from the commandline switches. The medium preset wasn't intended for transparency either.

You may also want to try:

lame --alt-preset 167 --lowpass 17.5 --nsmsfix 3 -Z

QUOTE
Is "--alt-preset standard -Y" currently the best compromise?
Also, why is the bitrate distribution so sharply peaked with
the "-Y" setting, compared to "--r3mix" or "-V3 -b96 -h -mj"?
Maybe I am just ignorant in saying this, but shouldn't bitrate
distribution be falloff more smoothly on either side of the avg
bitrate peak?


APS -Y is a high quality commandline but it tends not to reduce the bitrate enough (if the source material is limited >16KHz).

If you see a peakish bitrate distribution it could be from a high usage of short blocks. When APS uses lots of short blocks, it tends to utiltize a lot of 256 and 320kbps frames. This occurs because MP3 is trying to increase its time resolution and the only way to do this is with short blocks, which require many more bits than long blocks. For now, this isn't something you should worry about...APS is working correctly.

This post has been edited by mithrandir: Jan 18 2003, 05:32
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