Open source codecs

This is a listing of open-source multimedia codecs. That doesn't necessarily mean that further restrictions (such as software patents) don't exist for these codecs, which is the case for many of them. Note that codec is software, not a format — for example, video produced with the Xvid and FFmpeg MPEG-4 codecs is MPEG-4 ASP video.

Video codecs

*x264 - H.264 (MPEG-4 part 10) implementation. x264 is not a codec (encoder/decoder), it is just an encoder (it cannot decode video).
*Xvid - MPEG-4 part 2 codec, compatible with DivX.
*FFmpeg codecs - codecs in the libavcodec library from the FFmpeg project (FFV1, Snow, MPEG-1, MPEG-2, MPEG-4 part 2, MSMPEG-4, H.264, WMV2, SVQ3, MJPEG, HuffYUV, Indeo and others).
*Tarkin - an experimental lossy video codec under development by the Xiph.org Foundation based on 3-D wavelet compression
*Lagarith - lossless video codec
*Theora - Based on VP3, part of the Ogg Project.
*Dirac - Wavelet based codec created by the BBC.
*Huffyuv - Lossless codec from BenRG.
*OpenAVS

Audio codecs

*FLAC - Lossless compression.
*iLBC - Low bitrate voice compression.
*LAME - Lossy compression (MP3 format).
*Musepack - Lossy compression; based on MP2 format, with many improvements.
*Speex - Low bitrate compression, primarily voice; developed by Xiph.org.
*TTA - Lossless compression
*Vorbis - Lossy compression; developed by Xiph.org.
*WavPack - Hybrid lossy/lossless
*OpenAVS
*FFmpeg WMA - Reverse engineered WMA Standard codec
*FAAC and FAAD2 - open-source implementation of Advanced Audio Coding

Text Codecs

(generally used for subtitles/closed captioning)
*Writ.

See also

*FFmpeg, cross-platform, open source, audio and video codecs suite/library
*List of multimedia (audio/video) codecs
**Comparison of video codecs
**Comparison of audio codecs
*List of other software video players
*List of other software media players
*Comparison of media players
*Free file format