Add support for the matroska container format (extensions .mkv, .mka and .mks)

Packages describing “matroska” as local USE flag

Package“matroska” Flag Description
media-video/vlcEnable matroska support using reference libraries (fallback on other existing matroska support if disabled, i.e., matroska enabled FFmpeg)

All packages providing a “matroska” USE flag (1)