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.mkv

What is a .mkv file?

An open-source video container that can hold virtually any combination of video, audio, and subtitle tracks in a single file.

Safe format
Type Video
By Matroska.org
MIME video/x-matroska

Drop any file to identify it

We read file headers, not extensions. Nothing gets uploaded.

What is it

An open-source video container that can hold virtually any combination of video, audio, and subtitle tracks in a single file. MKV is the format of choice for high-quality video because it supports modern codecs (H.265, AV1, VP9) and features like multiple audio tracks, chapter markers, and embedded subtitles. It is the de facto standard for video archiving and media server libraries. The trade-off: not all devices and players support it natively. Smart TVs, game consoles, and phones often choke on MKV. Convert to MP4 for maximum compatibility.

Technical details
Full Name
Matroska Video Container
MIME Type
video/x-matroska
Developer
Matroska.org
Magic Bytes
1A 45 DF A3
Safety
.mkv is a known, safe format.
What opens it
VLC
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MPV
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Plex
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Convert with fwip

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FAQ
Why can't my TV play MKV files?
Many smart TVs and streaming devices have limited codec support. Convert to MP4 with <a href="https://fwip.app/tools/mkv-to-mp4/">fwip</a> for universal playback — it runs in your browser and your video never gets uploaded.
What's the difference between MKV and MP4?
Both are containers — they hold video and audio streams. MKV supports more features (multiple audio/subtitle tracks, chapter markers, more codecs) but MP4 plays on far more devices. MKV is the enthusiast's choice; MP4 is the safe choice for sharing.
How do I convert MKV to MP4?
Use <a href="https://fwip.app/tools/mkv-to-mp4/">fwip's MKV to MP4 converter</a>. It runs in your browser — no upload, no account, no waiting for a server to process your file.
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