Video conversion
Convert AVI to MKV
Updated Jul 2026
AVI is an older Windows video format that many modern apps, phones, and smart TVs no longer open cleanly. MKV is a newer, more flexible container built to hold the same video and audio without needing to re-encode. Converting on your own computer changes the container in place, no upload required, so quality stays identical.
- Extension
- .avi
- Type
- Video
- Typically
- Legacy Windows video
- Extension
- .mkv
- Type
- Video
- Typically
- High-quality video containers
Convert AVI to MKV on your own computer. Nothing uploads.
How to convert AVI to MKV
- Open Morphjet and drag in the AVI file, or a whole folder of them, that you want to convert.
- Choose MKV as the output format.
- Convert. Morphjet repackages the video and audio into the new container without re-encoding, and the MKV is written next to your original. Nothing leaves your machine.
AVI vs MKV: what actually changes
| AVI | MKV | |
|---|---|---|
| File size | Same underlying video and audio | Same, MKV just repackages what's already there |
| Quality | Original quality | Identical, no re-encoding needed for the swap |
| Opens everywhere | Reliable on older Windows software, patchy on phones and smart TVs | Reliable on nearly all modern media players and smart TVs |
| Multiple subtitle or audio tracks | Very limited, usually just one of each | Yes, can hold several side by side |
| Chapter markers | Not supported | Supported |
When to convert, and when not to
Convert AVI to MKV when you want a file that plays reliably on a modern media player, smart TV, or streaming box, or when you need to keep multiple subtitle tracks or audio languages in one file.
Keep the AVI if some older software you rely on, like a legacy Windows editing program, only reads that specific container.
Why not just use an online converter?
Converting a video online almost always means uploading the whole file to someone else's server first, which for a full-length video can take a while and leaves a copy sitting on storage you don't control. Morphjet repackages the AVI into MKV directly on your computer, so the video never has to leave your machine to change containers.
Questions
Does converting AVI to MKV lose quality?
No. Going from AVI to MKV is usually a straight repackaging of the same video and audio data, not a re-encode, so there's no quality loss.
Will the MKV play in the same programs my AVI did?
Not always. Software built specifically around AVI may not open MKV, but nearly every modern media player and smart TV handles MKV without extra plugins.
Does the MKV keep the subtitles and audio tracks from my AVI?
Yes, and it can actually hold more of them. Where AVI struggles to carry multiple subtitle or audio tracks in one file, MKV was built to hold several side by side.
Can I convert AVI to MKV without uploading the video?
Yes. Morphjet converts the file locally on your computer, so a large video never has to travel over the internet.
Why bother converting if the quality doesn't change?
Because AVI is an old format with patchy support on modern devices, while MKV is what most current players and TVs expect, and it can also hold chapters and multiple tracks that AVI can't.
Morphjet converts AVI, MKV, and 1,800+ other formats, all on your machine. Launching this July.