## MKV and MP4 Are Containers, Not Codecs
This is the most important thing to understand: MKV and MP4 are **container formats** (wrappers), not video codecs. The actual video quality is determined by the codec inside — H.264, H.265, AV1, etc.
A 1080p H.264 video encoded at the same bitrate will look **identical** whether it's inside an MKV or an MP4 container. The container doesn't affect quality.
## What MKV Offers That MP4 Doesn't
**Multiple audio tracks**: an MKV can contain English, Spanish, French, and Japanese audio tracks simultaneously. Users switch between them in their player. MP4 supports multiple audio tracks but the implementation is less standardized.
**Multiple subtitle tracks**: MKV supports SRT, ASS, SSA, PGS (Blu-ray image subtitles), and more — all in one file. MP4 subtitle support is more limited.
**Chapters**: built-in chapter markers for navigation.
**Any codec**: MKV has no codec restrictions. MP4 supports a specific (though broad) set of codecs.
**Open source standard**: MKV is open. The specification is publicly available.
## What MP4 Offers That MKV Doesn't
**Universal device support**: MP4 works everywhere — smart TVs, game consoles, phones, tablets, web browsers, streaming platforms — with no additional software.
**Web streaming (HTML5)**: browsers play MP4 natively via `