Hi Suresh, How did you measure the MOS scores? Good to see we are comparable to AMBE on clean speech.
There is no algorithm in Codec 2 to handle tones or background noise, so it tends to fall over. These low it rate codecs are highly optimised for speech so need special code to handle non-speech signals. For FreeDV we use the Speex noise reduction in front of Codec 2 which helps with noise. It's something I'd like to add in the future, pls contract me directly if your company would like to sponsor development of these features. Cheers, David On 05/11/15 00:26, Suresh Thiriveedi wrote: > Hi, > > We want to add the codec2 to our product and I just downloaded the > latest code. I built and tried our sample pcm files (typically we use > these files to compare MOS and bit exactness among various codecs) to > get the MOS scores. I'm surprised to see that for tone and mixed speech > with tone and noise sample, the MOS score is very less as below. > > For the normal voice samples i got MOS score around 2.7 for 2.4K and 2.8 > for 3.2K. But for sine_wav I got 0.346 for 3.2K and -(minus)0.182 for > 2.4K. Where as for the mixed speed with noise and tone, got 1.651 for > 2.4K and 1.220K for 3.2K. > > Is there any known limitation for the tone transcoding in codec2? For > voice, it is comparable with AMBE but for tone, it is not. Far > difference.Could someone please comment? > > Attaching the sample files for the reference. > > Thanks > Suresh > > > ------------------------------------------------------------------------------ > > > > _______________________________________________ > Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > ------------------------------------------------------------------------------ _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
