Hey Kristoff, On 10/26/2012 05:47 PM, Kristoff Bonne wrote: > Hi, > > > > On 26-10-12 10:44, David Rowe wrote: >> Hi Jimmy, >> >> Very good work .... nice to be able to hear the effect f each bit >> getting messed up. > I second that. A nice example of the advantages of open source: the > ability to learn how something works!!! :-) > Good job Jim!
Thanks! > > Just wondering: > > Is there a difference in the format of the codec2 frames for voiced and > unvoiced frames? > As far as I understand the theory, voice and unvoiced frames have very > different characteristics; so I guess, the format of the codec2 frame > will also be different. > > Do the bits have a different means when used for a voiced or a unvoice > frame. And what if the 20 or 40 ms timeslot contains both voiced and > unvoiced (10 ms) frames? > > Does it make sence to do Jimmys exercise again, once for only voiced > framed and once for only unvoiced frames? Hey just took a look at the code in the codec2.c and it seems to be using the same function to find the voiced bits within the frame. I imagine they'd have a similar effect across the data rates. It's very easy to run the tests again though. I'm going to get code going for log spectral distance and then do some tests over the bit rates. > > If this would be the case, we could try to work out a different FEC > and/or interleaver for voiced or unvoiced frames. > > Or am I making things to complicated? I don't think so :) . Interleaving especially (it doesn't even add to the bit rate) and FEC have a great opportunity to increase the quality of codec2 over radio. To me that means a better reception and faster adoption by the ham community and others. Separating the important bits and smearing them on the data stream will be good for burst errors. If the log spectral distance readings agree with subjective judgements we could base the interleaver on its measurements. By the way its awesome to hear that you've contacted ka9q about FEC. Found his website at the beginning of my interest in DSP and convolutional codes around a year ago. He's got some really nice work! > > > >> Cheers, >> David > 73 > Kr. Bonne KG4SGP - Jim > ------------------------------------------------------------------------------ > WINDOWS 8 is here. > Millions of people. Your app in 30 days. > Visit The Windows 8 Center at Sourceforge for all your go to resources. > http://windows8center.sourceforge.net/ > join-generation-app-and-make-money-coding-fast/ > _______________________________________________ > Freetel-codec2 mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 ------------------------------------------------------------------------------ WINDOWS 8 is here. Millions of people. Your app in 30 days. Visit The Windows 8 Center at Sourceforge for all your go to resources. http://windows8center.sourceforge.net/ join-generation-app-and-make-money-coding-fast/ _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
