AVI to MP4 Converter
Convert AVI videos to MP4 format.
Drop your AVI file here
or click to browse · max 500 MB
Settings
Slower = better compression, longer conversion time
128k for speech · 192k for general use · 320k for music
FFmpeg WASM (~25MB) will be downloaded on first use and cached by your browser.
AVI to MP4 Converter
Converts legacy AVI (Audio Video Interleave) files to modern MP4 format. AVI was developed by Microsoft in 1992 and while still used, MP4 with H.264 offers dramatically better compression (50-80% smaller files) and universal compatibility across modern devices.
What is it used for?
- Modernizing old video archives and home recordings
- Dramatically reducing file size (AVI files are often unnecessarily large)
- Making videos playable on smartphones, tablets, and smart TVs
- Uploading to modern video platforms and social media
- Converting CCTV/surveillance footage for sharing
Step-by-Step Guide
- Click upload or drag and drop your AVI file
- Adjust quality and encoding settings in the settings panel
- Click 'Convert to .MP4' to start conversion
- Preview the result - compare file sizes to see the savings
- Download your modern MP4 file
How it works
Upload an AVI file and click Convert. FFmpeg re-encodes the video to H.264 codec and audio to AAC in an MP4 container. This typically reduces file size by 50-80% while maintaining quality.
AVI vs MP4 (H.264)
| Feature | AVI | MP4 (H.264) |
|---|---|---|
| File Size | Very large | 50-80% smaller |
| Codec Support | Legacy codecs | Modern H.264 |
| Streaming | Not suitable | Optimized |
| Device Support | PC only | Universal |
| Metadata | Limited | Rich metadata support |
Tips & Best Practices
- Large AVI files may take several minutes to convert in the browser
- If the original AVI used high-quality settings, use CRF 20-22 to preserve quality
- AVI to MP4 conversion typically offers the best file size reduction ratio
Frequently Asked Questions
How much smaller will the MP4 be?
Typically 50-80% smaller. AVI files often use uncompressed or old codecs, while H.264 is highly efficient. A 1GB AVI might become 200-400MB as MP4.
Will converting affect quality?
With the default CRF 23 setting, quality loss is minimal and often imperceptible. Since many AVI files use older codecs, the H.264 encoding may actually look better at smaller sizes.
Can this convert DivX/XviD AVI files?
Yes, FFmpeg supports virtually all codecs found in AVI containers including DivX, XviD, MJPEG, and uncompressed formats.
Privacy & Security
This tool uses FFmpeg compiled to WebAssembly (WASM). The WASM binary (~25MB) is downloaded from a CDN on first use and cached by your browser. All file processing happens locally on your device - your files are never uploaded to any server. This makes it safe for sensitive, private, or confidential media files. Large files may take longer to process depending on your device's CPU and available memory.