Am 2011-11-03 09:47, schrieb Patrick Strasser: > Am 2011-11-02 00:29, schrieb David Rowe: >> On Tue, 2011-11-01 at 21:52 +0000, Trevor . wrote: >>> --- On Tue, 1/11/11, ZPO <[email protected]> wrote: >>>> Should the FEC be considered part of the baseline CODEC or >>>> a part of the external transport protocol? >>> >>> FEC is nothing to do with the CODEC it's in the transport protocol. >> >> For low bit rate digital speech at low channel SNRs you can get much >> better performance by considering source coding, FEC, and even >> modulation together. >> >> It's very wasteful just to apply blanket FEC to a >> 2000 bps digital voice stream. > > I do not think that just trowing "some FEC" on a codec yields a sensible > combination. One needs to know the system very well to choose the right > components that fit exact together and take advantage of each other.
One component I forgot: With different revisions of the codec and possible different profiles with respect to frame size/delay, differential encoding and the like, some meta information is necessary for a receiver to decode a stream. Also frame sync could be an issue, if the transport channel does not provide it on a different level. do plans exits about this aspect? Regards Patrick 73 de Patrick -- Engineers motto: cheap, good, fast: choose any two QTH: JN77rb http://sat.mur.at/ Patrick Strasser OE6PSE <oe6pse at wirklich priv at> ------------------------------------------------------------------------------ RSA(R) Conference 2012 Save $700 by Nov 18 Register now http://p.sf.net/sfu/rsa-sfdev2dev1 _______________________________________________ Freetel-codec2 mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freetel-codec2
