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, making it suitable for a wide range of applications, including Voice over IP (VoIP), videoconferencing, in-game chat, and music streaming. Opus supports a wide range of bitrates, from very low bitrates suitable for speech to higher bitrates for high-quality music. It also features low latency, making it ideal for real-time communication. Opus combines the technologies from two codecs: SILK, developed by Skype, and CELT, developed by Xiph.Org Foundation. It is royalty-free and open-source, making it a popular choice for developers and users alike. Opus files are typically smaller than other audio formats like MP3 or AAC at comparable quality levels, making them efficient for storage and transmission. The format supports variable bitrate (VBR), constant bitrate (CBR), and average bitrate (ABR) encoding modes, providing flexibility for different use cases.