Opus is a totally open, royalty-free, highly versatile audio codec. Opus is unmatched for interactive speech and music transmission over the Internet, but is also intended for storage and streaming applications. It is standardized by the Internet Engineering Task Force (IETF) as RFC 6716 which incorporated 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, videoconferencing, in-game chat, and even remote live music performances. It can scale from low bit-rate narrowband speech to very high quality stereo music. Supported features are:
You can read the full specification, including the reference implementation, in RFC 6716. An up-to-date implementation of the Opus standard is also available from the downloads page.
15 October, 2014
The is a beta release for the upcoming 1.1.1. This release focuses on code optimizations, especially on x86, MIPS and ARM. The quality should be unchanged. downloads page.
5 December, 2013
After more than two years of development, we have released Opus 1.1. This includes:
3 December, 2013
This is the third and likely last release candidate for 1.1. It fixes several bugs in the fixed-point build. Floating point is unaffected. The code is available from the downloads page.
27 November, 2013
This second release candidate fixes an alignment issue on ARMv5E and improves the Neon optimizations. Other platforms are unaffected. The code is available from the downloads page.
26 November, 2013
We're getting closer to the final 1.1 with this new release that further improves surround encoding quality. It also includes better tuning of surround and stereo for lower bitrates. The complexity has been reduced on all CPUs, but especially ARM, which now has Neon assembly for the encoder. At last, there are a few bugfixes. The code is available from the downloads page.
11 July, 2013
Following up on the alpha, here's now the beta release for version 1.1. Monty wrote a nice demo page showing off all the improvements in 1.1. As for version 1.0.3 it includes a backport of the new 1.1 surround API (see the demo) as well as some minor bugfixes. The code is available from the downloads page.