Files with the .OPUS extension contain audio data in a lossy compression in the “Ogg Opus” format. This type of compression uses SILK and CELT codecs and was devised for online streaming of sound of bit rates variable between 6 and 510 kilobytes per second, which is why it is used mostly in software requiring transmission of audio through the Internet – VoIP – videoconferences, and game chatrooms.

Since the transmissions are coded in real-time, it is a rare sight to find these files physically saved on data storage devices.