.mkv File — Matroska Video

MKV (Matroska Video) is a free, open-standard multimedia container format that has become the preferred format for high-quality video content, particularly for media enthusiasts and archival purposes. Named after Russian nesting dolls (matryoshka), the format can contain virtually unlimited numbers of video, audio, subtitle, and attachment streams in a single file. MKV supports all modern video codecs (H.264, H.265, VP9, AV1), audio codecs (FLAC, AAC, DTS, Dolby TrueHD, Atmos), and subtitle formats (SRT, ASS, PGS, VobSub). Key features include chapter markers, metadata tags, embedded fonts for styled subtitles, attachments, and ordered chapters that can reference segments in other files. MKV uses EBML (Extensible Binary Meta Language) for efficient, extensible storage. The format is the standard for Blu-ray remuxes, anime fansubs, and high-quality video distribution because it imposes no restrictions on codec combinations or stream counts. MKV is widely supported by media players, smart TVs, streaming devices, and media servers like Plex and Jellyfin.