Hello, > I assume that Bruce was referring to the LSP VQ codebook training I was > working on with David, but it seems like you're using the "old" scalar > VQ, right?
Yes, this is relative to SVN r310. I already wondered if the codec couldn't be improved at this point when seeing the code :) > In any case, there would like be some retraining/retuning > required for 12.8 because you would probably need more than 10 LSPs. > Possibly 12 to 16 LSPs. I am not 100% certain where LSPs are concerned -- I understand them mathematically but not as an audio technique. So correct me if I'm wrong but: I'm assuming (without detailed understanding) that the number of LSPs relates directly to how many harmonics we want to pass around; higher sample rate would enable a fair amount even on high-pitch voice. Right? I am not aiming for better resolution on low-pitch voices; but from having my neighbour's children ring my front-door phone I've learnt that I cannot distinguish their voices at G.711's 8 kHz sample rate. Codec2 would not be able to do better than that if it used 8 kHz, so that should go up before analysing the frequency bands, was my view. And the underexploited FFT in Codec2 made that really easy. If we can achieve the same number of harmonics on those high voices as on the low-pitch ones, I think we've got an advantage over G.711 in this respect. I do still need to sample (enthousiastic) children's voices, though. I only sent this to the list because the topic of power-of-two FFTs came up on this list. > Actually, you can't just change the sampling rate without changing > anything else. You not only need to use more than 10 LSPs, see above, > but there may > be implications for the pitch (encoding and search), covered in the patch with factors and a new pitch filter, which I reconstructed for 12.8 kHz after reverse-engineering the one for 8 kHz, > the VAD is this contained in Codec2? I didn't see it... > and maybe more. always willing to hear about them :) Thanks for the input! Cheers, -Rick ------------------------------------------------------------------------------ Keep Your Developer Skills Current with LearnDevNow! The most comprehensive online learning library for Microsoft developers is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3, Metro Style Apps, more. Free future releases when you subscribe now! http://p.sf.net/sfu/learndevnow-d2d _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
