Hi, If any one wants .wav versions of the files:
http://kg4sgp.com/audio/brians-samples.zip KG4SGP - Jim On 11/14/2012 07:58 PM, David Rowe wrote: > Hi Brian, > > Apologies for taking so long to reply, I have had my head down working > on the fdmdv2 GUI program with Dave Witten, which we hope to release > before the end of this year. > > Brian, I listened to the samples and I do think there is some > improvements on some samples. I'd agree with you that the samples sound > more natural on average. Nice work ! > > Some comments: > > 1/ Many of the samples sound less clicky or buzzy, more natural. > > 2/ However the level of many samples has shifted down, they > sound quieter > > 3/ Also some of the samples sound more band-limited, this might > affect intelligibility, not sure. morig is a good example of > this, sounds like some HF filtering. The power law might be > doing this, enhancing higher amplitude LF sounds more while > attenuating lower energy HF energy. > > 4/ the background noise on mmt1 was noticeably reduced. Maybe > this is positive effect of (3), i.e. annoying HF noise has been > attenuated, which in this case dominates the sample, so we don't > miss the HF speech energy. > > It would be good if we can keep (1) & (4), but improve on (2) and (3). > > I have been trying to remove the clicky/buzzy artefact of Codec 2 for > some time, usually by playing with phase models. Your work shows some > interesting possibilities. The recent LPC post filter also manipulated > the spectral amplitudes, and helped reduce the buzzy effect. So this > looks like a good area for further work. I might have been looking at > the wrong area (phase models), when trying to improve the naturalness. > > It could also indicate the speech can be made more natural by reducing > the HF energy. > > The reason I averaged the LPC spectrum over an entire harmonic was to > get around some issues with low pitched speakers and the LPC model. > Perhaps it's time to re-examine these assumptions. > > BTW to test these sorts of improvements I usually start with c2sim and > test without quantisation, e.g. > > c2sim ../raw/hts1a.raw --phase0 --lpc 10 -o hts1a_test.raw > > (maybe with the post filters on as well). That lets us separate > quantisation issues and helps reduce the number of interacting > variables. It would also be good to separate out the effect of (i) how > u are sampling the harmonics and (ii) the power law. > > This could be a switch we add to the decoder, as it won't affect the bit > stream. > > Others on the list - pls listen to these samples as well and give us > some feedback. > > Cheers, > > David > > > On Mon, 2012-11-05 at 22:54 +0000, Brian Smith wrote: >> Hi David. >> There are now samples at: >> http://www.shapeseeker.com/samples >> either as individual files or bundled up as a samples.tar.bz2 file. They >> are the standard codec2 raw/ directory samples encoded/decoded at >> 1200bps using the original (e.g. hts.1200.raw) and modified (e.g. >> hts.1200b.raw) versions for comparisons. Encode/decode is done with: >> >> c2enc 1200 xxx.raw xxx.c2; c2dec 1200 xxx.c2 xxx.1200.raw; c2dec.new >> 1200 xxx.c2 xxx.1200b.raw >> >> I can convert to wav as well if you want. >> >> David Rowe wrote: >>> Hello Brian, >>> >>> That sounds interesting. Could you pls post (i) some before and after >>> samples that illustrate the change and (ii) the command line you used to >>> test? >>> >>> Cheers, >>> >>> David >>> > > > ------------------------------------------------------------------------------ > Monitor your physical, virtual and cloud infrastructure from a single > web console. Get in-depth insight into apps, servers, databases, vmware, > SAP, cloud infrastructure, etc. Download 30-day Free Trial. > Pricing starts from $795 for 25 servers or applications! > http://p.sf.net/sfu/zoho_dev2dev_nov > _______________________________________________ > Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 ------------------------------------------------------------------------------ Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
