At Meta, we prioritize real-time communication for all users, especially those with slower connections or older devices. We have developed the Meta Low Bitrate (MLow) codec to improve audio quality, particularly on low-speed connections. MLow outperforms Opus by providing higher quality at lower bitrates while maintaining lower complexity. MLow is now being implemented in Instagram and Messenger calls, with WhatsApp to follow. MLow enables more effective Forward Error Correction (FEC) strategies, enhancing audio quality in packet loss scenarios. MLow utilizes classic CELP concepts with advancements in excitation generation, parameter quantization, and coding schemes. We are excited about the future of MLow and our ongoing efforts to enhance audio quality for all users.
https://engineering.fb.com/2024/06/13/web/mlow-metas-low-bitrate-audio-codec/