On Wed, May 14, 2008 at 8:32 PM, Bruce P. [email protected] wrote:
I’ve written a draft proposal at http://codec2.org/
to create some good open voice codecs and solve the problem of proprietary
AMBE on D*STAR.
Please read it, and send comments directly to me - [email protected]
I’ll be at Hamvention this weekend to discuss this, too.
Hey Bruce… Some points to add to your page:
Low density parity check codes are unpatented (by virtue of being
invented than forgotten ). They have performance on par with turbo
codes, and may someday be proven to be mathematically equivalent.
The open codec world is alive, though not very large. Make sure you
talk to Jean-Marc Valin [email protected] (author of
We’ve been working on a new lowlatency codec for speech and music,
CELT, and are about to public a paper on it. (celt-codec.org).
While CELT wouldn’t be useful for narrowbanded voice some of the
components of CELT would be very useful in an AMBE killer.
(Particularly CWRS, the algebraic vector quantizer). CELT itself
could be used for a 10-20khz wide mode (40-60kbit/sec with decent SNR)
to replace FM with something with much greater quality if there was
interest… But a lower bandwidth mode will be far more interesting.