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Lowpass cutoff freq. in relation to quality level, Which max. freq. is stored at q0 / q1 / q2 ... ?
LigH
post Dec 13 2009, 23:19
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For LAME MP3, it is simple to try and notice a table which describes how the lowpass cutoff frequency is set in relation to a VBR level per default, because LAME verbosely reports it at the console.

So I wonder if you can show me a similar overview - or at least a rough estimation - how it develops for Ogg Vorbis (original / aoTuV tunings) in relation to the quality levels.

I already read in another thread that Vorbis usually applies a cutoff at a minimum of 20 kHz. But for a low quality level it will possibly be noticably below, rather close to 16 kHz?

Of course one could compare sonographs of encoded noise, but hey, aoyumi is here, he might know it at first hand...

This post has been edited by LigH: Dec 13 2009, 23:23


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lvqcl
post Dec 13 2009, 23:40
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With this command line:
CODE
oggenc2.exe -q 0 --advanced-encode-option lowpass_frequency=22 test.wav

oggenc says:
QUOTE
Changed lowpass frequency from 15,100001 kHz to 22,000000 kHz


Also psych_44.h has the following values:
CODE
12.9,14.3,15.1,15.8,16.5,17.2,18.3,20.1,48.,999.,999.,999.,999.

I assume it is lowpass frequencies (in kHz) for -2...10 quality settings (and 44.1 kHz input).

This post has been edited by lvqcl: Dec 13 2009, 23:41
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LigH
post Dec 14 2009, 09:10
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So it looks like -q 7 and above are unrestricted ... interesting.

Thank you, that appears to be the table another user in our board was looking for.


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