Opus is a totally open, highly versatile audio codec. It is primarily designed for interactive speech and music transmission over the Internet but is also applicable to storage and streaming applications. It incorporates technology from Skype's SILK codec and Xiph.Org's CELT codec.
Opus can handle a wide range of audio applications, including Voice over IP, video conferencing, in-game chat, and even remote live music performances. It can scale from low bit-rate narrowband speech to very high-quality stereo music.