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encode with lame and with no lowpass frequency ?
arfgh
post Oct 4 2011, 20:55
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how to encode with lame but without a lowpass frequency and obtain in the final result the full spectrum sound. That is 22050 Hz.
I have seen some mp3 files encoded by unknown encoder that was capable to do it.

thx in advance
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pdq
post Oct 4 2011, 21:14
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There is a switch for that. I recommend that you do not use it.
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mjb2006
post Oct 5 2011, 00:16
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This was just discussed in two recent threads:
link and link

In summary:

A lot of work has gone into making sure LAME's default settings produce ideal results. There are knobs you can tweak, but you must realize that the MP3 format has limitations (particularly in regard to the highest frequency band) that have already been taken into account, and you're working with limited bandwidth as well. An adjustment to improve the sound in one way is quite likely to degrade the sound in another way. Do you want the higher frequencies to be preserved if it means adding noise across the entire spectrum?
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greynol
post Oct 5 2011, 00:48
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At least one of the original posters in those two links acknowledged what was being said about possible reductions in quality.


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arfgh
post Oct 5 2011, 15:19
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QUOTE
* -k full bandwidth

Tells the encoder to use full bandwidth and to disable all filters. By default, the encoder uses some highpass filtering at low bitrates, in order to keep a good quality by giving more bits to more important frequencies.
Increasing the bandwidth from the default setting might produce ringing artefacts at low bitrates. Use with care!


this was extracted from the lame 3.93.1 documentation.
I think that this encoder version was the last to allow the use of the -k switch.

it warns about use with care (with low bitrates) but, what about if we use the cbr 320 bitrate ?
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db1989
post Oct 5 2011, 18:16
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QUOTE
I think that this encoder version was the last to allow the use of the -k switch.
Another way in which to disable the lowpass is given at the first link provided by mjb2006 above.

QUOTE
but, what about if we use the cbr 320 bitrate ?
Still diverting bits to frequencies that you probably cannot hear, possibly reducing quality in frequency bands that you can. Why would its being CBR make any substantial difference to this fact?
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Aleron Ives
post Oct 6 2011, 03:14
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QUOTE (db1989 @ Oct 5 2011, 09:16) *
Why would its being CBR make any substantial difference to this fact?

I think he was (incorrectly) assuming that 320 CBR is such a "generous" bitrate that it would be possible to preserve all the high frequencies without any quality loss in the lower ones.
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arfgh
post Oct 16 2011, 21:26
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well, i have tried to disable the lowpass with the lame 3.98.4, and was no possible. using lowpass -1 and using lowpass 22050, etc.
none of them have disabled the lowpass.

I have made tests with other lame versions, to reach teh 'famous' 3.93.1, and none of them execept this last one was able to disable.

The thing that i want to know is if the result using the '3.93.1 cbr320 -k' switch is able to produce best quality results than the 'cbr320 in 3.98.4'.
I know that these frequencies are not audible, but the result is best quality... or not ?
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punkrockdude
post Oct 18 2011, 21:19
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Use version 3.99 and V 0 for no or very little low passing. Regards.
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arfgh
post Oct 19 2011, 15:09
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but i want to use the cbr 320, not the vbr.

this lame 3.99 is strange, because the lowpass -1 is again working, but it implements a lowpass at 21.5 Khz, Strage !
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greynol
post Oct 19 2011, 16:48
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Have you ever even bothered to conduct a double-blind listening test?

This thread will close until you can demonstrate to me via personal message that the answer is yes.


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