Opus is a lossy audio coding format developed by the Xiph.Org Foundation and standardized by the Internet Engineering Task Force, designed to efficiently code speech and general audio in a single format, while remaining low-latency enough for real-time interactive communication and low-complexity enough for low-end ARM3 processors. Opus replaces both Vorbis and Speex for new applications, and several blind listening tests have ranked it higher-quality than any other standard audio format at any given bitrate until transparency is reached, including MP3, AAC, and HE-AAC.

Is a standard for storing audio files in Apple operating systems. It was developed in 1988 based on the IFF format and is a lossless format – audio data is stored in an uncompressed form. In essence, AIFF is an analog to WAV for the Apple Macintosh platform.