Matroska Multimedia Container, or more popularly known in the file extension of .mkv (for video with or without subtitles and audio), .mka (audio-only) or .mks (subtitles only), is an open standard free container format. Matroska itself is not an encoding format for multimedia files, but serve as a universal format for storing and hold unlimited amount of common multimedia content of video, audio, picture or subtitle tracks inside a single file.

When opening or playing back the Matroska files (.mkv, mka or .mks) in Windows operating system, including Windows 7 and Windows Vista, “Windows can’t open this file” dialog will be prompted, instructing user to let Windows to go online to look up program used to open the file automatically, or manually select from a list of programs that are installed on the computer.

When Windows Media Player is selected, or even if the Matroska file opens automatically in WMP, the media file won’t play with error message such as “Windows Media Player cannot play the file. The Player might not support the file type or might not support the codec that was used to compress the file”, as by default, there is no codec (encoder and decoder filter) support for .mkv, .mka or .mks file format or type in Windows.

Also important to note is that as Matroska is a container which can contains many streams or tracks with different audio and video encoding and compression formats. Thus, the unable or cannot playback the media files issue may also caused by no proper decoders (codec or filter) for the streams or tracks inside the Matroska container. The content inside a .mkv file can be made up of H.264, RealVideo (RM), DivX video, and one or more AC3, AAC, DTS or Vorbis audio tracks, causing the codecs for these formats must also be installed on the system.

Many non DirectShow-based standalone media players such as VLC Player and GOM Player support the playback of Matroska files, however, it’s not the case for DirectShow-based media player, which include Windows Media Player. For DirectShow player, user will need to install proper codecs and filters in order to playback the Mastroska media files.

Tip: To help users to identify the codecs that were used in MKV files, Matroska developer provide codec identification tool named matroskadiag.exe, which can be used to check MKV file to identify and report which DirectShow decoder filters are required to be installed.

For users who want to use Windows Media Player and other DirectShow-based player such as BSPLayer, Redlight Player and WinAmp, to view and play back .mkv or .mka files, here’s a few codecs and filters that can be installed to provide the support.

CCCP (Combined Community Codec Pack)

CCCP is a simple playback pack for Windows with the goal of supporting the majority of video formats in use today. The codecs pack provide almost all decoding filters required to play .mkv (matroska video) and .mka (matroska audio) files under DirectShow players, such as Windows Mediaplayer, MPC (Media Player Classic), Zoomplayer and TCMP (The Core Media Player).

CCCP installs support for container formats such as AVI, MKV, MP4, FLV, TS, 3GP, OGM, OGG; video codecs such as MPEG-1, MPEG-2, MPEG-4 ASP, Xvid, DivX, 3ivx, lavc, MPEG-4 AVC (H.264), WMV, VC-1, VP6F, Theora, H.263+; audio codecs such as MP3, MP2, MP1, AC3, DTS, AAC, Vorbis, FLAC, TTA, WavPack, AMR, LPCM, IMA ADPCM and subtitle formats such as SRT, Vobsub (.idx + .sub), SSA and ASS.

Download CCCP

Haali Media Splitter

Haali Media Splitter provides the most up to date DirectShow filter to read Matroska files. It support almost all Matroska elements is implemented in the core parser library. The DS splitter supports multitrack and multisegment linked and/or concatenated files. The codecs pack also provides support for AVI, MP4, OGG/OGM and MPEG TS playback.

Download Haali MKV Media Splitter: MatroskaSplitter.exe

DivX for Windows

DivX 7 for Windows is a free download that provides codec support for high-quality digital videos, including HD H.264 (.mkv) videos with AAC audio, DivX or DivX Plus files (.divx, .avi), and videos created using all previous versions of DivX technology.

Download DivX 7 for Windows: DivXInstaller.exe

Of course, there are many other codec packs available that can support Matroska files playback. But these all-inclusive codec packs are packing too many codecs and filters, which may be simply overwhelming, or may cause corruption to DirectShow filters.