MKV is a flexible container format. It can hold video, audio, subtitles, chapters, and metadata, but it is not itself a video codec.
Container format explainer

What Is

MKV?
Matroska Video

MKV is a flexible container format. It can hold video, audio, subtitles, chapters, and metadata, but it is not itself a video codec.

Beginner-friendly • Practical examples • Plain English
MKV • Matroska • Container

TL;DR

MKV stands for Matroska Video.

MKV is a container, not a codec.

MKV is common for movies, subtitles, and multi-audio files.

What MKV means

MKV stands for Matroska Video. The name usually refers to files with the .mkv extension.

An MKV file is a container. It packages one or more streams together, such as video, audio, subtitles, chapters, and metadata.

Why MKV files are common

MKV vs MP4

FormatStrengthTrade-off
MKVVery flexible; great subtitle and multi-track supportNot as universally supported by TVs, phones, and browsers
MP4Excellent compatibility for sharing and streamingLess flexible for some advanced library use

Frequently asked questions

What does MKV stand for?

MKV stands for Matroska Video.

Is MKV a codec?

No. MKV is a container format, not a codec.

What is MKV used for?

MKV is used for video files that may include multiple audio tracks, subtitles, chapters, and metadata.

Is MKV better than MP4?

MKV is more flexible, while MP4 is usually more compatible. Better depends on your use case.

Why will my TV not play MKV?

Your TV may not support the MKV container, or it may not support the specific video or audio codec inside the MKV file.