AVI to MP4 converter
Turn old AVI clips into universally playable MP4 files that work on phones, browsers, and editors. Conversion runs entirely in your browser, so your video never leaves your device.
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AVI (Audio Video Interleave) is a container Microsoft introduced in the early 1990s, and clips saved in it usually carry older codecs like DivX, Xvid, or MPEG-4 ASP. Those codecs predate the H.264/AAC pairing that phones, HTML5 video players, and modern editors expect, which is why an AVI often refuses to open in a browser or on an iPhone even though it plays fine on an old Windows PC. Converting to MP4 re-encodes the video to H.264 and the audio to AAC, then wraps them in the container almost every device and platform reads natively.
Creators reach for an AVI to MP4 converter when they have footage from a screen recorder, an older camcorder, or a legacy render that they now want to edit, upload, or pair with a track. Because the conversion runs in your browser through WebAssembly, the file is processed on your own machine rather than sent to an upload server, so nothing private leaves your device. That local approach also lets you convert archival or personal clips you'd rather not hand to a third-party website.
How it works
- 1
Drop in your AVI file.
- 2
Let it re-encode to H.264/AAC MP4.
- 3
Download the MP4.
When to use it
- Turning a DivX or Xvid AVI from an old camcorder into an MP4 you can drop straight onto a CapCut, Premiere, or DaVinci Resolve timeline without a 'codec not supported' error.
- Preparing an AVI clip for Instagram Reels or TikTok, which reject the AVI container and expect an MP4 or MOV upload.
- Fixing a downloaded AVI that shows audio but a black screen, or won't open at all, in Chrome, Safari, or the iOS Photos app.
AVI vs MP4
| AVI | MP4 | |
|---|---|---|
| Lossless | No | No |
| Typical size | Large (older codecs) | Efficient (H.264/AAC) |
| Best for | Legacy video | YouTube & universal video |
| Compatibility | Windows, older players | Practically everything |
FAQ
Will converting to MP4 improve my video's quality?
No. Re-encoding to H.264 can't add detail that isn't in the source, and any transcode is lossy, so expect quality equal to or slightly below the original. It mainly makes the file play everywhere.
Why does this take longer than a simple format change?
AVI usually holds DivX/Xvid video that MP4 can't just carry over, so the video is re-encoded to H.264 frame by frame. That's real compression work, so larger or longer clips take more time than a quick remux.
Will the MP4 end up smaller than my AVI file?
Usually, yes. Older AVI codecs like Xvid and DivX are far less efficient than H.264, so re-encoding at a sensible bitrate often lands the MP4 well below the original size at similar visual quality. If your AVI already used a high bitrate the savings shrink, and deliberately raising quality can occasionally make the file larger.
Why won't my AVI play on my phone or in a browser in the first place?
Browsers, iOS, and Android don't support the AVI container natively, and they can't decode the DivX or Xvid streams many AVI files use. That combination is what gives you a black screen, an error, or sound with no picture. MP4 with H.264 and AAC is the format those platforms actually decode, which is the whole reason to convert.
Can I just upload an AVI straight to YouTube, Instagram, or TikTok?
YouTube does accept AVI uploads, though it recommends MP4. Instagram and TikTok generally won't take an AVI and expect MP4 or MOV, so converting first avoids a rejected or failed upload. Handing the platform an H.264 MP4 also skips an extra server-side transcode and tends to publish faster.
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