If you don't know who David Rowe is - his work is amazing. He's the main force behind Codec2, one of the few opensource ultra-low bitrate speech codecs out ther

If you don't know who David Rowe is - his work is amazing. He's the main force behind Codec2, one of the few opensource ultra-low bitrate speech codecs out there. The project hit ~700 bps recently! (https://github.com/freedv/codec2/blob/master/src/codec2.h https://github.com/freedv/codec2/blob/master/src/codec2.h - I think it was actually at 400 bps @ one point, but I guess it got scaled back)