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alt preset extreme -m s ??
juglesh
post Jan 10 2002, 23:35
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just wanted to make sure this command line was ok. no conflict or anything? I assume i could use -m s with preset standard as well?

thanks,
juglesh
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user
post Feb 2 2002, 17:00
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http://www.digital-inn.de/showthread.php3?threadid=8212

stereo vs. joint stereo - mid/side

Hi,

I would not damn unregistered so hard.

Please remember, everybody has different tastes.

alt presets have been tuned regarding different quality aspects of music.

One of those is pre echo.

ff123 proved, that ap standard is much better regarding pre echo.

That was to expect, as castanets is a hard example for pre echo and alt
presets have been tuned regarding pre echo.



But unreg. did not spoke of pre echo artifacts, he concerns about stereo
image.


And some of his arguments are quite well.
If you want to gain a lot quality and you are not worrying about some bytes
in resulting bitrate, then you don't need js in extreme setting.

My above sentence is of course not exact enough.
VBR mode choses a suitable bitrate regarding a certain level of quality.
If you force VBR to use only ms/stereo frames, then the bitrate will
increase (not much compared to actually alt extreme setting).
One exception:
What happens, if music is so complex that VBR would take a higher bitrate
than 320 ?
Then it would take a 320 mid/side frame. That is the best compromise regarding
all, frequency, tonality, stereo image etc.

RESULT:

From a theoretical point of view you need only joint stereo / mid/side sometimes with
difficult music in 320 kbit frames. All other possibilities could be solved
with stereo frames, as long as you stay below 320.

Overall resulting bitrate would be a little increased over actual alt preset
extreme.


At the moment users like unreg. have a nearly perfect solution:

Overriding --alt-preset extreme

with:

--alt-preset extreme -ms


This solution has got one disadvantage:

If music is so difficult, complex, that Lame VBR mode would decide to take a
higher bitrate than 320, because then 320 mid/side would be taken and it would be
best compromise. But with overriding switch -ms this solution is not
possible.


Perhaps it is a new idea for Dibrom, to tune --alt-preset extreme regarding
stereo image.
I would suggest following:
Either : ap exterme with normal/old --nssafejoint switch. I remember with
this switch there was more use of stereo frames than with ap extrme now.
Or: a kind of "If.... then...." routine : in alt extreme: generally -ms
frames, only if "Lame" wants more than 320 , then lame takes 320 mid/side. This
would lead to only use of stereo frames in bitrates below 320, and in 320: --nssafejoint is enabled, so
both, ms, mid/side is possible in 320 kbit frames.

I hope I described my ideas, suggestions in a way, you can understand them.



aahhh, for unreg there two ad hoc solutions:

1. as described above:
overriding --alt-extreme with -ms :

--alt-preset extreme -ms

(with disadvantage of no use of joint stereo in 320 kbit frames)


2. simply use:

--alt-preset insane

disadvantage: now you have 320 CBR.
But you told us: You would not worry about some extra kbits/s !!!

So this is the best solution for anybody who has concerns about quality.


But a further investigation of improving stereo image in apexterme could not
be bad.
Perhaps the samples of unreg. can prove or not artifacts in stereo image in
apextreme.
ABXing has to be done.


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