[opus] quality opus_demo vs opusenc

Jean-Marc Valin jmvalin at jmvalin.ca
Tue Oct 15 11:37:41 PDT 2013


I suspect the main difference is due to time alignment of the samples
and the exact trimming at the beginning and at the end of the encoded
files. I also note that there's a missing "--" in front of "bitrate" and
only one "-" instead of two for cvbr in your opusenc command line. Make
sure both are also linked to the same libopus (opusenc could be using
the system libopus 1.0.x while opus_demo is from git). In the end, the
quality should be almost the same, but the files won't be identical due
to minor differences in the way the first and last frame are handled.

Cheers,

	Jean-Marc

On 10/15/2013 05:22 AM, Quilino Cifuentes wrote:
> Hi,
> I have found differences in quality between opus_demo and opusenc/opusdec.
> 
> I used for both applications the same raw pcm file,16 bit,48khz,litle
> endian. i use libopus 1.1-beta and opus-tools-0.1.7.
> 
> The command for opus_demo is:
> 
> opus_demo audio 48000 1 64000 -cvbr -framesize 10 in.pcm out.pcm
> 
> For opusenc/dec:
> 
> opusenc --raw --raw-chan 1 bitrate 64 -cvbr --framesize 10 in.pcm in.opus
> 
> opusdec in.opus out.pcm
> 
> the PEAQ value for opus_demo is -0.152 and for opus-tools is -0.449
> 
> Should I expect the same quality or are opus_demo and opusenc/dec
> different by definition?
> 
> Thanks,
> Quilino
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