Matroska

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Matroška (Матрёшка)
Matroska 2010.svg
File extension : .mkv, .mk3d, .mka, .mks
MIME type : video / x-matroska audio / x-matroska
(no IETF recommendation)
Developed by: Matroska.org
Initial release: 2003
Type: Container format
Container for: multimedia


Matroska , after Russian matryoshka , is a container format for audio and video data. Matroska files either have the ending .mkvfor video data or .mkafor pure audio data. The ending is .mksused for subtitles , while the ending has been .mk3dintroduced for three-dimensional content .

Matroska supports various video codecs, including MPEG-1 , MPEG-2 , MPEG-4 , H.264 , HEVC , RealVideo , Theora , Dirac , and audio codecs, such as AAC , AC3 , DTS , WAV , MP3 , Vorbis and FLAC as well as others Formats for subtitles ( VobSub ) and extended meta information.

The developers see the format as an alternative to existing container formats such as AVI , OGM / Ogg , ASF , MOV or MP4 . The specifications are publicly available and can be freely used in software applications. The core libraries are under the GNU LGPL , the parser under the BSD license .

Properties of the format

The format uses EBML , a binary XML format, to describe the container. This enables a high degree of flexibility in the format and at the same time ensures that further developments of the format can still be read by older parsers.

Similar to DVDs , the Matroska specification allows u. a. the division of files into chapters, seamless branching , and the use of several audio tracks, for example for different language versions. The aspect ratio can be changed during output. The standard also provides menu functions for user guidance; A corresponding implementation has not yet been found in either the authoring tools or the playback programs.

In addition to audio and video, Matroska containers can also contain text streams (e.g. for subtitles) or files of any other format. The frame rate of the video stream does not have to be constant, but may fluctuate ( variable frame rate encoding , VFR). The synchronization of audio and video tracks can be provided with a suitable shift during creation and afterwards by adjusting the meta information.

Matroska files are often smaller than comparable files in other formats, as the data structure of the container creates only a low overhead . The maximum file size is 2 in the present specification 56 - 2 bytes , which is about 7 × 10 16 corresponds to byte or 72 petabytes.

Matroska can be used as a streaming format and then transmitted via HTTP - streaming via RTP is not recommended.

distribution

Since 2003 there has been a free muxer for Matroska with MKVToolNix .

DivX Inc. uses MKV as the sole container format for their DivX 7 format, which was published in January 2009, but in an implementation that is not completely standard-compliant.

In May 2010, Google released the multimedia format WebM as an open source project, which is based on the freely purchased VP8 video codec , the free Vorbis audio codec and a simplified version of Matroska. There is only a simplified file structure and only allows the codecs VP8 / VP9 for video and Vorbis for audio tracks.

In October 2014, Microsoft confirmed that Windows 10 will natively support Matroska containers and the HEVC codec. The support was first available in Windows 10 Technical Preview Build 9860.

Support of MKV in hardware devices

Mainly MKV files with the video codecs H.264 Level 4.0 and 4.1, MPEG-4 ASP (Advanced Simple Profile) and audio tracks in the formats AC3, MPEG-1 Layer 2 ( MP2 ) and Layer 3 (MP3) are supported, Advanced Audio Coding (AAC) and Ogg Vorbis. However, it is not simply possible to support all conceivable MKV videos in hardware in this way, due to the enormous variety of possible video and audio streams in MKV files. Defined playback profiles, so-called subsets from Matroska, which would allow this more easily, are still missing in the standard.

Web links

Individual evidence

  1. ↑ Specification Notes - Mime Types. matroska.org, accessed June 8, 2010 .
  2. ↑ a b Matroska open source A / V container format officially released , May 1, 2003
  3. ↑ a b Matroska Format Specifications. matroska.org, accessed June 8, 2010 .
  4. ↑ matroska.org
  5. ↑ DivX 7 completed. In: heise online. January 6, 2009, accessed June 8, 2010 .
  6. ↑ archive.org
  7. ^ The WebM Project - FAQ. Retrieved June 8, 2010 .
  8. ↑ Gabriel Aul: HEVC also supported in-box. , Twitter . October 31, 2014. Retrieved November 3, 2014. 
  9. ^ John Callaham: Microsoft: Windows 10 will support the HEVC video compression standard , Windows Central. November 1, 2014. Retrieved November 3, 2014. 
  10. ↑ Bogdan Popa: Microsoft Confirms MKV File Support in Windows 10 , Softpedia . November 3, 2014. Retrieved November 15, 2014. 
  11. ^ Gabe Aul: New build available to the Windows Insider Program , Microsoft . November 12, 2014. Retrieved November 15, 2014.