Quick Verdict
Use AVI when…
AVI has no practical advantages over MP4 for any modern use case. The only reason to use AVI is if you have a specific legacy application that requires it.
Use MP4 when…
Use MP4 for everything — universal compatibility, streaming support, mobile playback, social media uploads, and better codec efficiency. MP4 is the correct modern choice.
AVI vs MP4: Feature Comparison
| Feature | AVI | MP4 |
|---|---|---|
| Developed | 1992 by Microsoft | 2001 by MPEG group |
| Mobile device support | None — not supported on iOS or reliably on Android | Universal — plays on every phone, tablet, smart TV |
| Web/browser support | None — browsers can't play AVI natively | Full — plays in all browsers via HTML5 video |
| Streaming support | Not designed for streaming | Full streaming support — HTTP progressive download and HLS |
| Variable frame rate | Not officially supported | Supported — used by screen recorders and phones |
| Modern codec support | H.264 possible but uncommon; no H.265, VP9, AV1 | All modern codecs — H.264, H.265, VP9, AV1 |
| File size at same quality | Typically larger (uses older codecs by default) | Smaller (H.264 is more efficient than DivX/Xvid) |
| Upload to YouTube/social | Accepted but slower processing | Recommended — fastest processing, best compatibility |
When AVI wins
- ✓Developed: 1992 by Microsoft
- ✓Mobile device support: None — not supported on iOS or reliably on Android
- ✓Web/browser support: None — browsers can't play AVI natively
When MP4 wins
- ✓Developed: 2001 by MPEG group
- ✓Mobile device support: Universal — plays on every phone, tablet, smart TV
- ✓Web/browser support: Full — plays in all browsers via HTML5 video
Frequently asked questions
Why is AVI still around if MP4 is better?
AVI persists because: (1) Legacy video archives — people have years of AVI files from old camcorders and downloads. (2) Some older software only outputs AVI. (3) Screen recording tools and older game capture software default to AVI. (4) Some CCTV systems still record in AVI. None of these are reasons to create new content in AVI — they're reasons why old AVI files still exist.
Can I convert AVI to MP4 for free?
Yes — FormatDrop's video converter handles AVI to MP4 conversion in your browser for free. For batch conversion of large libraries: VLC (free), HandBrake (free), or FFmpeg (command-line, free) are the best options. All are completely free with no limitations.
Does AVI to MP4 conversion reduce quality?
For AVI files with H.264 video (some modern AVI files): remuxing to MP4 has zero quality loss — the video data is copied, not re-encoded. For AVI files with DivX, Xvid, or MPEG-4 Part 2 video (the vast majority of old AVI files): re-encoding to H.264 MP4 is required. At CRF 18–23 (high quality), the quality loss is imperceptible or actually an improvement over the degraded DivX source.
More comparisons
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