Browser edition: files stay on your device. Up to 100 MB total and 10 minutes. First use downloads a 32 MB engine. Some formats depend on codec support. Public-link downloading is not ready on this free deployment.
Convert AVI to MP4
Convert AVI to MP4 online for free. Smart remux when possible, high-quality encoding when not.
How to convert AVI to MP4
- Add your fileDrop it on the page, choose it from your device, or paste it with Ctrl+V.
- ConvertAdjust settings if you like, then press the button. You'll see live progress.
- Browser processing uses original files on your device. Public-link downloading is unavailable.
What happens to your file
AVI files are common for old DVD players, legacy software, archived home videos, but not every app or device opens them. MP4 is the better choice for sharing, uploading to social networks, playing on any device. Spool converts AVI to MP4 with FFmpeg — real decoding and encoding, not a renamed file extension.
A real re-encode. AVI usually contains MPEG-4 Part 2 (Xvid/DivX) video with MP3 audio, which MP4 players can't decode, so Spool re-encodes to H.264 video and AAC audio. "Balanced" is visually indistinguishable from the source for most videos; "High" uses a lower CRF for archiving; "Smaller file" trades a little sharpness for a much smaller file.
Most AVI files use Xvid/DivX (MPEG-4 Part 2) video and MP3 audio. Those codecs are not supported by iPhone, QuickTime or many web players, so we re-encode to H.264 and AAC. The result is usually smaller than the original AVI at the same visual quality.
Settings
- Quality — High, Balanced, Smaller file. Balanced keeps the original streams when possible (no quality loss, very fast).
- Resolution — Same as source, 4K (2160p), 1440p, 1080p, 720p, 480p, 360p, 240p
- Audio bitrate — Auto · keep original if possible, 320 kbps · best, 256 kbps, 192 kbps · standard, 128 kbps · small, 96 kbps, 64 kbps · voice
AVI vs MP4
| AVI | MP4 | |
|---|---|---|
| Full name | Audio Video Interleave | MPEG-4 Part 14 |
| Created by | Microsoft, 1992 | ISO / MPEG, 2001 |
| Type | Video container | Video container |
| Typical contents | MPEG-4 Part 2 (Xvid/DivX) video with MP3 audio | H.264 or H.265 video with AAC audio |
| Best for | old DVD players, legacy software, archived home videos | sharing, uploading to social networks, playing on any device |
| Strength | Plays on old DVD/USB players and legacy Windows software | Plays everywhere, including iPhone, Android, Windows and macOS |
| Weakness | Large files compared with MP4 | Lossy: every re-encode loses a little quality |
About AVI
- Type
- Audio Video Interleave
- Contains
- MPEG-4 Part 2 (Xvid/DivX) video with MP3 audio
- Use
- old DVD players, legacy software, archived home videos
About MP4
- Type
- MPEG-4 Part 14
- Contains
- H.264 or H.265 video with AAC audio
- Use
- sharing, uploading to social networks, playing on any device
FAQ
Will converting AVI to MP4 reduce quality?
A small amount, because the video has to be re-encoded. With the default "Balanced" setting (H.264 CRF 23) the difference is not visible for most videos; choose "High" to minimize it.
How long does it take?
Re-encoding runs at roughly real-time or faster for 1080p video. You'll see live progress and the time remaining.
Can I convert several AVI files at once?
Yes. Drop up to 10 files at a time — each one is converted in parallel and you can download them individually or all at once.
Is there a file size limit?
Convert and edit files on your device. The browser edition accepts up to 100 MB total, media up to 10 minutes and video up to 4K. Codec availability and device memory can limit individual jobs.
Is this AVI to MP4 converter free and safe?
Yes. There are no pop-ups, redirects or fake download buttons, and no software to install. Files are transferred over HTTPS, processed in isolated job folders and deleted automatically.
Will the MP4 play on iPhone and Android?
Yes. MP4 with H.264 or HEVC video and AAC audio plays natively on iPhone, iPad and Android, as well as on Windows, macOS and smart TVs.