[opus] Opus application_mode==AUDIO, 20ms framing issue?

Jean-Marc Valin jmvalin at jmvalin.ca
Fri Jun 3 17:12:53 UTC 2016

Hi Kevin,

Are you saying that the quality is good at 20 ms and bad at 10 ms, or
the reverse? Also, is this speech or music? What tool, what options? In
general, it helps a lot if you post the sample (input and output).



On 06/03/2016 12:48 PM, Kevin Connor wrote:
> Hi Opus list,
> I'm noticing a discontinuity in the quality between use of 10ms and
> 20ms framesize for mode=AUDIO  at a bitrate of about 28000.
> Quality drops audibly for voice signals when encoded at 20ms
> framesize, versus quality at 10ms.   This effect is mode=AUDIO only.
> Using mode==VOIP shows no sig. difference between 10 and 20ms framing
> at this bitrate.      Pesq totally overreacts, as it is wont to do :)
> However, I do hear a slight drop. Admittedly, 28kbps is a low bitrate
> to be running in mode=AUDIO.     Is this effect known?  Is there a
> difference in processing with audio mode between 10ms and (other
> framesizes)?   I reckon it will go away if I throw some more bitrate
> at it,  but wanted to understand it a bit better.
> Thanks very much, KevinC 
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