Opus

77.43

Royalty-free open audio codec by IETF, which incorporated SILK from Skype and CELT from Xiph.org, to serve higher sound quality and lower latency at the same bitrate.

Further reading:

1. Can I use page for: Opus
2. Introduction of Opus by Mozilla
3. Google's statement about the use of VP8 and Opus codec for WebRTC standard
4. Microsoft Edge feature request on UserVoice