Is a media data format created by Apple. Named 'Quicktime' and is opened by a program with the same name. This format contains several tracks, each of which can store audio, video or text. Supported by a large number of encodings and in a single file, each element can use its own codec.
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.