AVI to MP4 Converter Convert AVI video files to modern MP4 format in your browser.

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AVI to MP4 Converter

Convert AVI video files to modern MP4 format in your browser.

Upload AVI

Drag and drop your AVI file or click to browse.

Convert to MP4

Click Convert to transform your AVI into MP4 format.

Download the MP4

Download your converted MP4 file instantly.

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What Is AVI to MP4 Converter?

The AVI to MP4 Converter transforms AVI (Audio Video Interleave) video files into modern MP4 format in your browser. MP4 is the most widely supported video format, compatible with virtually all devices, players, and platforms. AVI files are often large and may not play on modern devices. This tool bridges the gap by re-encoding your AVI content into efficient MP4. The conversion uses HTML5 video capabilities to decode the AVI (where browser-supported) and re-encode as a modern format. All processing happens locally, ensuring your files remain private.

Why Use AVI to MP4 Converter?

MP4 is universally compatible with all modern devices
Significantly smaller file sizes compared to AVI
No server uploads — complete privacy
No software installation needed

Common Use Cases

Modernize Archives

Convert old AVI recordings to MP4 for modern device compatibility.

Mobile Playback

Make AVI videos playable on smartphones and tablets.

Web Sharing

Share AVI videos on web platforms and social media by converting to MP4.

Storage Savings

Reduce file sizes by converting from AVI to efficient MP4 compression.

Technical Guide

This tool attempts to load the AVI file using the HTML5 Video element. Browser support for AVI varies — Chrome and Edge generally handle common AVI codecs. The video is decoded and frames are captured via a Canvas element. The captured frames along with any audio are fed to MediaRecorder for re-encoding in a web-compatible format. For AVI files with uncommon codecs that browsers can't decode, the tool provides guidance to use ffmpeg.wasm or a desktop converter. The output is optimized for web delivery with efficient compression. Audio tracks are re-encoded using the browser's available audio codecs (typically Opus or AAC).

Tips & Best Practices

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Browser support for AVI varies — Chrome/Edge offer the best compatibility
2
Some AVI codecs may not be supported by the browser decoder
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The output MP4 will typically be much smaller than the original AVI
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For unsupported AVI codecs, consider using ffmpeg.wasm

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Frequently Asked Questions

Q Can all AVI files be converted?

Most common AVI codecs are supported. Some older or proprietary codecs may not be decodable in the browser.

Q How much smaller will the MP4 be?

MP4 files are often 50-80% smaller than equivalent AVI files due to more efficient compression.

Q Is the conversion private?

Yes. Everything processes in your browser — no files are uploaded to any server.

Q What if my AVI won't play?

If the browser can't decode your AVI codec, try using a desktop converter or ffmpeg.wasm for broader codec support.

Q Does it preserve audio?

Yes, audio tracks are preserved and re-encoded in a compatible format when possible.

About This Tool

AVI to MP4 Converter is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.