Experimental version of LPCNet that has been used to develop FreeDV
2020 - a HF radio Digial Voice mode for over the air experimentation
with Neural Net speech coding. Possibly the first use of Neural Net
speech coding in real world operation.

From https://people.xiph.org/~jm/demo/lpcnet/ :

Work in progress software for researching low CPU complexity
algorithms for speech synthesis and compression by applying Linear
Prediction techniques to WaveRNN. High quality speech can be
synthesised on regular CPUs (around 3 GFLOP) with SIMD support (AVX,
AVX2/FMA, NEON currently supported). The code also supports very low
bitrate compression at 1.6 kb/s.