[opus] Stereo voice not being retained

[Orestes Zoupanos]

Hey Kevin!

Once you start dropping under (I think) 32kbps, the codec naturally
starts losing stereo separation for the benefit of quality.
If you really want perfect stereo at 16kbps CBR (this is horrifically
low in my opinion) you might be better off splitting the audio and
encoding each part at 8kbps CBR.
Or, there may be a magic "enforce 100% stereo" one could pass? (doesn't
look like it at
https://mf4.xiph.org/jenkins/view/opus/job/opus-tools/ws/man/opusenc.html)

You can always ask stuff at the #opus channel at
https://webchat.freenode.net/

On 16/11/2015 17:37, Honeyager, Kevin S. wrote:
>
> Hello,
>
>  
>
> I’ve been using Opus on an STM32 M4 platform for speech coding in mono
> mode.  I thought I’d try stereo for grins to see if I can handle the
> CPU load, and I’m getting a return code of -1 from opus_decode_float
> (using CBR and 40ms frames).
>
>  
>
> I decided to try the opusenc and opusdec tools to just see how the
> command line apps would behave.  I am getting decoded audio, but I am
> losing the stereo separation.  My test file has speech obtained with a
> Tascam Recorder, and I spoke directly into each mic individually.  I
> can clearly hear the stereo separation in the recorded audio. I do not
> hear any stereo separation once I encode from wav and decode back to
> wav.     My encoding command line is “opusenc --hard-cbr --bitrate
> 16.000 --complexity 10 --framesize 20 stereo_voice.wav temp.opus”.  My
> decoding script is: “opusdec  --force-wav temp.opus decode.wav”. 
> Opusenc reports that my encoded file is 2 channels (coupled) and
> opusdec reports that my file is 2 channels.  Can someone tell me how
> to retain my stereo separation?  If I can’t get stereo separation from
> the codec, there’s no point in me investigating the error return in my
> ARM application.
>
>  
>
> Kevin
>
> 	
>
> * *
>
> * *
>
>  
>
>  
>
>  
>
>
>
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