Opus is a lossy audio coding format developed by the Internet Engineering Task Force (IETF) and standardized as RFC 6716. It is designed for efficient encoding of speech and general audio, offering high quality at low bitrates. Opus excels in a wide range of applications, including Voice over IP (VoIP), videoconferencing, in-game chat, and music streaming. It supports constant bitrate (CBR), variable bitrate (VBR), and constrained variable bitrate (CVBR) encoding modes, allowing for flexibility in balancing quality and bandwidth usage. Opus also features low algorithmic delay, making it suitable for real-time communication. The format incorporates both SILK (Skype's speech codec) and CELT (Constrained Energy Lapped Transform) technologies, enabling it to handle a variety of audio content effectively. Opus is royalty-free and open-source, promoting its widespread adoption and integration into various software and hardware platforms. Its adaptability and efficiency make it a popular choice for modern audio applications where bandwidth and quality are critical considerations.