ogg

Ogg is a free, open container format for multimedia data maintained by the Xiph.Org Foundation. It is designed to efficiently store and stream multiple independent streams—such as audio, video, and text—within a single file, using a modular, open specification that is not tied to any particular codec.

The Ogg container does not define audio or video encoding; instead, it wraps streams encoded with various codecs such as Vorbis (audio), Opus (audio), Speex (audio), Theora (video), or other formats that support the Ogg container. Each stream is independently encoded and multiplexed into a continuous bitstream, organized into pages that facilitate streaming and random access. Metadata can be stored using Vorbis comments and additional headers, and chapters or coordinates can be included.

History and licensing: Ogg originated from the development work of the Xiph.Org Foundation in the late 1990s as a patent-unencumbered container for multimedia. It and its codecs are released under permissive licenses; the project emphasizes free use and broad compatibility.

Adoption and compatibility: Ogg is widely supported by free and open-source tools such as VLC, FFmpeg, and MPlayer, as well as many hardware players and operating systems. Common file extensions include .ogg for generic audio/video, .ogv for video-only content, and .opus for Opus within Ogg; other extensions exist for specific codecs.