Hi David, Ok perfect, I will look into the source code for the energy extraction. Thank you so much for the info!
Cheers, Marko -----Original Message----- From: David Rowe <da...@rowetel.com> Sent: April 11, 2018 4:40 PM To: freetel-codec2@lists.sourceforge.net Subject: Re: [Freetel-codec2] Codec2 and packet loss Hi Marko, Repeat a decode with the last encoded packet. The decoder will then interpolate internally to provide a smooth decoded speech output signal. You could use packet n-1 or n+1 to replace missing packet n. I'd choose the packet with the highest "energy" - in codec2.c you can see how the energy is extracted from the bit stream for each mode. > I'm also wondering how strong is the dependency between subsequent encoded > packets? If there is a discontinuity due to packet loss will the decoder have > some period of instability or is each encode/decode pair independent? OK what you mean is memory effects. Not much in most Codec 2 modes, as we don't use predictive encoding of parameters much. For say 1300 and 700 bit/s modes, a bit error in frame n will only affect frame n+1. IIRC think 1200 is the exception, as it has predictive coding of pitch and energy, - David > > Thanks for your help, > Marko > > -----Original Message----- > From: David Rowe <da...@rowetel.com> > Sent: April 11, 2018 3:39 PM > To: freetel-codec2@lists.sourceforge.net > Subject: Re: [Freetel-codec2] Codec2 and packet loss > > Hi Marko, > > Just repeat the last (or maybe next) packet. My tests indicate a PER of 10% > to be the limit for useful speech quality. > > - David > > On 12/04/18 06:46, Marko Milutinovic wrote: >> Hello, >> >> What is the best way to deal with packet loss when using Codec2? For >> example if I send out 10 (1-10) packets and on the receiving side I >> get >> 1,6,7,8,9 (after buffering) what would be the best way to minimize noise? >> >> Do I just sequentially decode the packets I have received and plug in >> NULL audio in between or is there something else that can be done to >> interpolate? >> >> Thanks, >> >> Marko >> >> >> >> --------------------------------------------------------------------- >> - >> -------- Check out the vibrant tech community on one of the world's >> most engaging tech sites, Slashdot.org! http://sdm.link/slashdot >> >> >> >> _______________________________________________ >> Freetel-codec2 mailing list >> Freetel-codec2@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/freetel-codec2 >> > > ---------------------------------------------------------------------- > -------- Check out the vibrant tech community on one of the world's > most engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Freetel-codec2 mailing list > Freetel-codec2@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > > ---------------------------------------------------------------------- > -------- Check out the vibrant tech community on one of the world's > most engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Freetel-codec2 mailing list > Freetel-codec2@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/freetel-codec2 > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2 ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Freetel-codec2 mailing list Freetel-codec2@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/freetel-codec2
