> For the complete documentation index, see [llms.txt](https://gia-duong-duc-minh.gitbook.io/notes/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gia-duong-duc-minh.gitbook.io/notes/computer/opus-codec.md).

# Opus Codec

Opus is a totally open, royalty-free, highly versatile audio codec

## Technology

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 bitrate narrowband speech to very high quality stereo music. Supported features are:

* Bitrates from 6 kb/s to 510 kb/s
* Sampling rates from 8 kHz (narrowband) to 48 kHz (fullband)
* Frame sizes from 2.5 ms to 60 ms
* Support for both constant bitrate (CBR) and variable bitrate (VBR)
* Audio bandwidth from narrowband to fullband
* Support for speech and music
* Support for mono and stereo
* Support for up to 255 channels (multistream frames)
* Dynamically adjustable bitrate, audio bandwidth, and frame size
* Good loss robustness and packet loss concealment (PLC)
* Floating point and fixed-point implementation

Opus has the low algorithmic delay (26.5 ms by default) necessary for use as part of a real-time communication link, networked music performances, and live lip sync; by trading-off quality or bitrate, the delay can be reduced down to 5 ms