Lyra is Google's neural speech codec, built to deliver intelligible voice at extremely low bitrates — around 3 kbps and below, far past the point where classical codecs collapse into noise. Instead of hand-designed signal processing, it uses a machine-learned model: the encoder extracts a compact set of speech features and a neural generator reconstructs natural-sounding speech from them at the decoder. Its target use is keeping calls connected on very poor or congested networks where even Opus's lowest modes struggle. Lyra's later versions are built on SoundStream-style techniques, and it represents, alongside EnCodec and SoundStream, the shift from traditional to neural audio coding for the hardest low-bitrate cases.
