There is only one file type that uses the .OPUS extension:
Opus Audio File
An OPUS file is an audio file created in the Opus format (also called "Ogg Opus"), a lossy audio format developed for Internet streaming. It uses both SILK (used by Skype) and CELT (from Xiph.Org) codecs and supports variable bit rates from 6 kb/s to 510 kb/s.
The Opus codec is used for Voice over IP (VoIP), video conferencing, in-game chat. The Opus format was standardized by the IETF and is maintained by Xiph.Org.
Since the Opus codec is primarily used for streaming, files with the .opus extension that are encoded with the Opus codec are not common.
You can open an OPUS file and play the audio it contains in the following media players:
- VideoLAN VLC media player (cross-platform)
- Foobar2000 (Windows)
- Opus Player (Android)
Updated: September 9, 2020