Compress AVI
Convert AVI to a much smaller MP4 with FFmpeg — running locally in your browser.
or drop files here
Maximum file size: 200MB per file
The encoder picks the highest bitrate that fits your target.
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About AVI Compression
AVI is an aging container with inefficient codecs, which is why AVI files are so large for their quality. This tool runs a full FFmpeg build compiled to WebAssembly inside your browser: it decodes your AVI, re-encodes the stream as modern H.264 MP4, and hands you a much smaller file — without uploading anything to a server. Old camcorder clips and archive footage finally fit into email and chat limits. Whether you are optimizing for the NBN, preparing myGov submissions, or sharing files across Australia's vast distances, this tool keeps your files light and quick to transfer — even on regional, fixed-wireless, and satellite connections, with no upload required.
When to Compress AVI Files
Old Footage
Shrink camcorder and digitized AVI archives for modern use
Email Attachments
Meet attachment limits that raw AVI always exceeds
Sharing
Send clips in MP4 that every player and platform accepts
Storage Saving
Reclaim disk space from legacy AVI collections
How to Compress an AVI File Online
Upload your AVI files
Choose one or more `.avi` videos from your device.
Pick mode, quality and resolution
Compress by quality, or enter a target size in MB and let the encoder fit it.
Compress and download
FFmpeg runs locally in your browser; download the smaller MP4 files when done.
Frequently Asked Questions
Why is AVI converted to MP4?
AVI usually wraps old codecs like DivX/Xvid that are inefficient and poorly supported. Re-encoding to H.264 MP4 typically cuts size by 50–80% while improving compatibility with phones, browsers and chat apps.
Does the file get uploaded anywhere?
No. The FFmpeg engine itself is downloaded once from a CDN and cached by your browser; your video files are processed entirely in local memory.
Why is the first compression slower?
The first run fetches the ~31MB WebAssembly engine. Afterwards it is cached and every compression starts immediately.
How big can input files be?
Up to about 200MB depending on your device memory, since everything runs in-browser. For larger files, split them first or use the 500MB-target MP4 tools on an already-converted copy.