AVI to MKV Converter
Convert AVI to MKV free — no upload, no signup
To convert AVI to MKV, drop your AVI video into the box below and click Convert. Fylo converts with ffmpeg running inside your browser, so nothing is uploaded and there's no signup or watermark. Repackage AVI into MKV without re-encoding.
Drop videos here
or tap to browse · paste with Ctrl+V · add many at once
Your files never leave your device
If the video already uses codecs that fit the new format, Fylo repackages it instantly with no quality loss.
Advanced
How to convert AVI to MKV
Add your AVI videos
Drag and drop AVI files into the box or tap to choose them. The converter engine (about 31 MB) downloads once, the first time you convert.
Choose quality (optional)
Balanced quality suits most videos. If the codecs already fit MKV, Fylo repackages the file instead of re-encoding it, with no quality loss.
Convert and download
Click Convert, then download each MKV file or all of them as one ZIP.
Why convert AVI to MKV?
Media servers handle MKV better than AVI: proper seeking, chapters and subtitles. Converting an AVI library to MKV modernises it without touching quality.
What happens when you convert AVI to MKV?
Fylo copies the AVI's existing video and audio streams into Matroska, so it's fast and lossless. Note that the old Xvid video stays Xvid — if you need smaller or more compatible files, convert to MP4 instead.
How does Fylo convert AVI to MKV?
Fylo reads the AVI with ffmpeg compiled to WebAssembly and writes a straight copy of every stream — Matroska accepts any codec, so nothing is re-encoded. Every conversion to MKV is a lossless repackage, so it finishes in seconds even for large files. Only the first video and audio track are kept, and the original resolution is preserved unless you pick 1080p, 720p or 480p under Advanced.
What's the difference between AVI and MKV?
AVI (Audio Video Interleave) was introduced by Microsoft with Video for Windows in 1992. It's based on the RIFF container used by WAV and stores interleaved chunks of audio and video. In the 2000s, AVI files with DivX or Xvid (MPEG-4 Part 2) video and MP3 audio were the standard for downloaded movies.
MKV is the Matroska container, an open standard first released in 2002. It can hold virtually any video, audio or subtitle codec, and any number of tracks — so one file can carry several languages, director's commentary and subtitles. WebM is a restricted subset of Matroska.
Learn more: AVI format guide · MKV format guide
| Property | AVI | MKV |
|---|---|---|
| Developed by | Microsoft | Matroska project (open standard) |
| Introduced | 1992 | 2002 |
| Typical video codecs | MPEG-4 Part 2 (Xvid/DivX), MJPEG | Any: H.264, HEVC, VP9, AV1… |
| Typical audio codecs | MP3, PCM, AC-3 | Any: AAC, Opus, FLAC, DTS, AC-3… |
| Plays in web browsers | No | Partly (Chrome/Edge for some codecs) |
| Compatibility | Windows, VLC, older DVD players and TVs | VLC, Plex, Kodi, most smart TVs; not iPhone or many editors |
| Best for | Legacy players, old Windows software | Movies with multiple audio and subtitle tracks |
Frequently asked questions
Does MKV improve the video quality?
No; the streams are identical. MKV just adds a more robust, feature-rich container.
Will Plex play the MKV?
Yes — Plex, Jellyfin, Kodi and VLC all handle Xvid inside MKV.
Is my AVI file uploaded to a server?
No. Fylo runs ffmpeg, the same engine used by professional video tools, compiled to WebAssembly inside your browser. Your AVI file is read directly from your device and never sent anywhere.
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