Video and audio file formats which support OGG audio and variable framerate video. File extensions: .mkv: video files.mka: audio files (compatible with a number of compression formats: MP2, MP3, Vorbis, AAC, AC3, DTS and PCM).mks: subtitles

Matroska (common file extensions being .mkv and .mka) is a project to develop a free software multimedia container format similar to Apple's Quick Time, MPEG's MP4 or Microsoft's Advanced Systems Format. It is named after the matryoshka/матрёшка. The official playback solution for the Windows operating system is the Combined Community Codec Pack.