Xiph.Org Foundation in the context of Windows Media Audio

Opus is a free and open source lossy audio coding format developed by the Xiph.Org Foundation and standardized by the Internet Engineering Task Force, designed for efficient low-latency encoding of both speech and general audio. Due to its lower latency relative to other standard codecs, Opus finds specific use cases in real-time interactive communication for low-end embedded processors. Opus replaces both Vorbis and Speex for new applications.

Opus combines the speech-oriented LPC-based SILK algorithm and the lower-latency MDCT-based CELT algorithm, switching between or combining them as needed. Bitrate, audio bandwidth, complexity, and algorithm choice can be adjusted for each individual frame. Opus has low algorithmic delay (26.5 ms by default) ideal for use as part of a real-time communication link, networked music performances, and live lip sync; by trading off quality or bitrate, the delay can be further reduced down to 5 ms. Its delay thus is significantly lower compared to competing codecs, which require well over 100 ms. Opus remains competitive with these formats in terms of quality per bitrate.

Ogg is a digital multimedia container format designed to provide for efficient streaming and manipulation of digital multimedia. It is maintained by the Xiph.Org Foundation and is free and open, unrestricted by software patents. Its name is derived from "ogging," jargon from the computer game Netrek, alluding to the high processing cost of early versions of the software.

The Ogg container format can multiplex a number of independent streams for audio, video, text (such as subtitles), and metadata. In the Ogg multimedia framework, Theora provides a lossy video layer. The audio layer is most commonly provided by the music-oriented Vorbis format or its successor Opus. Lossless audio compression formats include FLAC, and OggPCM.

Vorbis is a free and open-source software project headed by the Xiph.Org Foundation. The project produces an audio coding format and software reference encoder/decoder (codec) for lossy audio compression, libvorbis. Vorbis is most commonly used in conjunction with the Ogg container format and it is therefore often referred to as Ogg Vorbis.

Version 1.0 of Vorbis was released in May 2000. Since 2013, the Xiph.Org Foundation has stated that the use of Vorbis should be deprecated in favor of the Opus codec, an improved and more efficient format that has also been developed by Xiph.Org.

FLAC (/flæk/; Free Lossless Audio Codec) is an audio coding format for lossless compression of digital audio, developed by the Xiph.Org Foundation, and is also the name of the free software project producing the FLAC tools, the reference software package that includes a codec implementation. Digital audio compressed by FLAC's algorithm can typically be reduced to between 50 and 70 percent of its original size and decompresses to an identical copy of the original audio data.

FLAC is an open format with royalty-free licensing and a reference implementation which is free software. FLAC supports metadata tagging, album cover art, and fast seeking.

Constrained Energy Lapped Transform (CELT) is an open, royalty-free lossy audio compression format and a free software codec with especially low algorithmic delay for use in low-latency audio communication. The algorithms are openly documented and may be used free of software patent restrictions. Development of the format was maintained by the Xiph.Org Foundation (as part of the Ogg codec family) and later coordinated by the Opus working group of the Internet Engineering Task Force (IETF).

CELT was meant to bridge the gap between Vorbis and Speex for applications where both high quality audio and low delay are desired. It is suitable for both speech and music. It borrows ideas from the CELP algorithm, but avoids some of its limitations by operating in the frequency domain exclusively.

Theora is a free lossy video compression format. It was developed by the Xiph.Org Foundation and distributed without licensing fees alongside their other free and open media projects, including the Vorbis audio format and the Ogg container.

The libtheora video codec is the reference implementation of the Theora video compression format developed by the Xiph.Org Foundation.

Ogg is a digital multimedia container file format designed to provide for efficient streaming and manipulation of digital multimedia. It is maintained by the Xiph.Org Foundation and is free and open, unrestricted by software patents. Its name is derived from "ogging," jargon from the computer game Netrek, alluding to the high processing cost of early versions of the software.

The Ogg container format can multiplex a number of independent streams for audio, video, text (such as subtitles), and metadata. In the Ogg multimedia framework, Theora provides a lossy video layer. The audio layer is most commonly provided by the music-oriented Vorbis format or its successor Opus. Lossless audio compression formats include FLAC, and OggPCM.