Convert AVI to MP4 Online

Pick an AVI file and convert it to MP4 for universal playback. Works on every device and browser; the conversion runs on your device.

How it works

  1. Upload your AVI file. Drag your AVI video into DomeScribe. Older AVI files using DivX, Xvid, or MPEG-4 video are accepted.
  2. Select MP4. Choose MP4 as the output. Pick a resolution (1080p, 720p, or the source size) so DomeScribe re-encodes the video as H.264 with AAC audio — modern, efficient, and playable everywhere. Leaving everything on "Original" only repackages the old streams, which many players cannot decode inside an MP4.
  3. Let it encode. Click Convert. Encoding runs in your browser; a standard-definition AVI converts in a few minutes, HD sources take longer.
  4. Save the MP4. Save the result with a free account. The MP4 is usually much smaller than the AVI source and works on every current device.

Converter at a glance

Video formats
MP4, MOV, AVI, WebM, MKV, FLV — optional resolution (4K to 360p) and frame rate (60/30/24 fps)
Audio formats
MP3, WAV, FLAC, AAC, OGG, M4A
Privacy
Runs 100% in your browser (WebAssembly) — your file is never uploaded to a server
Speed
No upload wait — processing starts as soon as the in-browser engine loads (~31 MB, cached after the first run)
File size
Limited by your device's memory — up to about 500 MB works reliably
Watermark
None
Limits
Free — no monthly limit; runs on your device (a free account is needed to save the file)

Frequently asked questions

Why are AVI files so much larger than MP4?

AVI is a legacy container from the 1990s that often uses older, less efficient codecs like DivX or raw MPEG-4. MP4 with H.264 encoding — what DomeScribe produces — achieves the same visual quality at a fraction of the file size.

Can DomeScribe handle old AVI files with unusual codecs?

Common legacy codecs such as DivX, Xvid, MPEG-4 Part 2, and MJPEG are decoded by the in-browser engine. Very exotic or proprietary codecs may fail to load; if the file does not convert, try re-saving it with a desktop player first.

Will converting my AVI to MP4 improve the video quality?

A DomeScribe conversion will not add detail that is not in the original, but modern H.264 encoding can look cleaner at the same bitrate by reducing compression artifacts common in older codecs. The main benefit is a much smaller file that plays everywhere.

I have old home videos in AVI format — is this a good way to preserve them?

Converting to MP4 is a sensible preservation step: AVI support is declining in modern software and devices, while MP4 will remain the dominant format for years. Because nothing is uploaded, your home videos stay on your device throughout.

How long does AVI to MP4 conversion take?

Old AVI codecs should be re-encoded to H.264 for compatibility, and that runs on your device, so processing time depends on your hardware and the video length. A typical 1-hour standard-definition AVI converts in a few minutes on a recent laptop; HD sources and older machines take longer.

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