Hi, I'm learning a bit about HVXC right now, as defined in MPEG-4 Part 3.
I'm a big fan of Codec2, not least because in ham radio, digimodes (digital voice) is becoming quite popular. Codec2 is quite impressive of its ultra-low bandwidths, etc.
Now, I'd like to test HVXC against Codec2 a bit, but I can't find any listening samples, or encoders. If anyone can link me to those, that would be great.
Another thing is: when did the patent expire? I can't find any information about that, was it even patented? It was released as ISO/IEC standard in 1999, and then amended in 2000. As I understand it, the patent should've expired by now, but I'm not sure. As it is with AAC and MP3, it was covered but a bunch of patents, which were difficult to track down, as it isn't always 100% clear, whether a patent concerns that codec, or not.
However, I can't find anything about patenting pertaining to HVXC.