[CELT-dev] 22 kHz version of CELT

Gregory Maxwell gmaxwell at gmail.com
Thu May 28 07:18:54 PDT 2009

2009/5/28 Jean-Marc Valin <Jean-Marc.Valin at usherbrooke.ca>:
> Quoting Marc Padellini <marc.padellini at gmail.com>:
>> The results I get with CELT at 42 kbit/sec are also pretty good, but the
>> highest bands get some noise  in the 8-11 kHz frequency range. I am going to
>> see what I can do, and try to optimize the band allocation or other parts of
>> the codec. For comparison, AAC-LC achieves transparent quality for speech at
>> about 48 kbit/sec.
> It's funny because when we compared CELT to AAC-LD on 48 kbit/s speech, CELT
> actually turned out better. See http://people.xiph.org/~jm/papers/celt_tasl.pdf
> Could be a difference in samples, implementations, listener, ...

Details details.

Marc said "AAC-L*C*", Jean-Marc, we compared "AAC-L*D*".

Marc, What frame size are you using?  Larger frame sizes will tend to
perform better (and be a fairer comparison with AAC-LC) Although,
especially with your 22050 sampling rate you are probably reasonably
well outside of the area where we've spent time tuning CELT thus far.

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