PCMFlow is a lightweight audio decode and PCM flow library for Arduino. As is, voice audio had too high a bitrate for use in applications like ESP-NOW mesh networking . The G.722 wideband (HD voice) codec add-on for PCMFlow is aimed at  real-time two-way voice over packet radio / network  — VoIP, ESP-NOW transceivers, WebSocket / UDP voice links. G.722 carries 7 kHz audio at 16 kHz sampling using the same 64 kbps wire budget as G.711 — same packet size, twice the audio bandwidth. The codec core is the public-domain  sippy/libg722  (Steve Underwood / CMU); this library wraps it behind PCMFlow’s  PCMSource  /  PCMSink  interfaces. Headline use case — ESP-NOW HD-voice transceiver ESP-NOW carries up to 250 byte payloads. A 20 ms G.722 voice frame at 16 kHz produces exactly 160 bytes — same as G.711, but with twice the audio bandwidth. Raw 16 kHz mono 16-bit PCM at the same 20 ms is 640 byte; G.722 compresses  4× . PCMFlowG722’s own code is MIT licensed.…