MP4 to AVI Converter
Convert MP4 to AVI free — no upload, no signup
To convert MP4 to AVI, drop your MP4 video into the box below and click Convert. Fylo converts with ffmpeg running inside your browser, so nothing is uploaded and there's no signup or watermark. AVI uses Xvid-compatible MPEG-4 video and MP3 audio for older players.
Drop videos here
or tap to browse · paste with Ctrl+V · add many at once
Your files never leave your device
If the video already uses codecs that fit the new format, Fylo repackages it instantly with no quality loss.
Advanced
How to convert MP4 to AVI
Add your MP4 videos
Drag and drop MP4 files into the box or tap to choose them. The converter engine (about 31 MB) downloads once, the first time you convert.
Choose quality (optional)
Balanced quality suits most videos. If the codecs already fit AVI, Fylo repackages the file instead of re-encoding it, with no quality loss.
Convert and download
Click Convert, then download each AVI file or all of them as one ZIP.
Why convert MP4 to AVI?
Older DVD players, set-top boxes, car screens and USB-capable TVs often only play AVI files with Xvid/DivX video. Converting lets you watch modern MP4s on that hardware.
What happens when you convert MP4 to AVI?
AVI can't hold MP4's H.264 reliably on old players, so Fylo re-encodes the video to MPEG-4 Part 2 tagged as Xvid and the audio to MP3. Expect the AVI to be larger than the MP4 — often 1.5–3× — because the older codec is less efficient. Encoding takes roughly real time on a typical laptop.
How does Fylo convert MP4 to AVI?
Fylo reads the MP4 with ffmpeg compiled to WebAssembly and writes MPEG-4 Part 2 tagged as Xvid with MP3 audio — the combination old DVD players and TVs understand. MP4's usual codecs (H.264, H.265/HEVC, AV1) can't go into AVI as-is, so the video is re-encoded. Speed depends on your device: short phone clips take seconds, while on our slow test PC a 2-minute 1080p video took about 10 minutes. Only the first video and audio track are kept, and the original resolution is preserved unless you pick 1080p, 720p or 480p under Advanced.
What's the difference between MP4 and AVI?
MP4 (MPEG-4 Part 14) is a container format standardised in 2001 and based on Apple's QuickTime file structure. A container holds separately compressed video and audio streams plus metadata such as subtitles, chapters and cover art. Most MP4s use H.264 video and AAC audio; newer files may use H.265 (HEVC) or AV1.
AVI (Audio Video Interleave) was introduced by Microsoft with Video for Windows in 1992. It's based on the RIFF container used by WAV and stores interleaved chunks of audio and video. In the 2000s, AVI files with DivX or Xvid (MPEG-4 Part 2) video and MP3 audio were the standard for downloaded movies.
Learn more: MP4 format guide · AVI format guide
| Property | MP4 | AVI |
|---|---|---|
| Developed by | MPEG (ISO/IEC 14496-14) | Microsoft |
| Introduced | 2001 | 1992 |
| Typical video codecs | H.264, H.265/HEVC, AV1 | MPEG-4 Part 2 (Xvid/DivX), MJPEG |
| Typical audio codecs | AAC, MP3 | MP3, PCM, AC-3 |
| Plays in web browsers | Yes — every browser | No |
| Compatibility | Universal: phones, TVs, editors, social media | Windows, VLC, older DVD players and TVs |
| Best for | Sharing, uploading, streaming, editing | Legacy players, old Windows software |
Frequently asked questions
Why is my AVI so much bigger than the MP4?
MPEG-4 Part 2 (Xvid) needs more bits than H.264 for the same quality. That's the price of compatibility with old players.
Will subtitles be kept?
No. AVI has very limited subtitle support; burn subtitles in or keep the MP4 if you need them.
Is my MP4 file uploaded to a server?
No. Fylo runs ffmpeg, the same engine used by professional video tools, compiled to WebAssembly inside your browser. Your MP4 file is read directly from your device and never sent anywhere.
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