BYTETOOLS

MP4 to AVI Converter

Convert MP4 videos to AVI online, free. Re-encodes to MPEG-4 video with MP3 audio for older players and editors — all in your browser, nothing uploaded.

Drop an MP4 video here or click to browseYour video is processed locally and never uploaded. Long videos take a while to encode.

What is the MP4 to AVI Converter?

The ByteTools MP4 to AVI Converter turns a modern MP4 video into a classic AVI file that legacy media players, older editing software and some car and TV systems still expect.

  • MPEG-4 video + MP3 audio for maximum legacy compatibility
  • Three quality levels to balance size and sharpness
  • 100% local processing — your video is never uploaded
  • Built-in preview player before download
  • Free, unlimited, no watermark

How to use the MP4 to AVI Converter

  1. 1

    Drop an MP4 video onto the box or click to browse for one.

  2. 2

    Choose a quality level — higher quality means a larger AVI file.

  3. 3

    Click Convert to AVI and wait while the in-browser engine re-encodes it.

  4. 4

    Preview the result and download your AVI file.

About the MP4 to AVI Converter

The ByteTools MP4 to AVI Converter turns a modern MP4 video into a classic AVI file that legacy media players, older editing software and some car and TV systems still expect. The video is re-encoded with the widely compatible MPEG-4 codec and the audio with MP3, because the AVI container cannot carry AAC audio reliably.

It is useful whenever a device or program refuses an MP4: old versions of Windows Movie Maker, DVD-authoring tools, in-car entertainment systems and vintage hardware players. Pick a quality level, convert, preview and download — no watermark and no file-size games.

Everything runs 100% locally in your browser using a WebAssembly build of ffmpeg. Your video is never uploaded to a server, so private footage stays on your device. Note that in-browser video encoding is CPU-heavy, so large or long videos take a while — short clips finish quickly.

Frequently asked questions

How do I convert MP4 to AVI for free?

Drop your MP4 onto this tool, pick a quality level and click Convert to AVI. The conversion runs entirely in your browser and you download the AVI when it finishes — no upload, no account and no watermark.

Why does the AVI use MP3 audio instead of AAC?

The AVI container has poor and inconsistent support for AAC audio, and many of the old players that still want AVI cannot decode it. MP3 audio is the safe, universally supported choice inside AVI, which is why this tool re-encodes the soundtrack to MP3.

Does converting MP4 to AVI lose quality?

The video is re-encoded, so there is some generational loss, but at the High setting it is hard to notice. AVI files also come out larger than the source MP4 because the older MPEG-4 codec is less efficient than H.264.

Is my video uploaded to a server?

No. The whole conversion runs in your browser with WebAssembly, so the file never leaves your device. That also means speed depends on your own computer — long or high-resolution videos take noticeably longer than short clips.

Will the AVI play on old Windows PCs and DVD players?

In most cases yes. MPEG-4 video with MP3 audio in an AVI container is the combination that DivX/Xvid-era players, older Windows software and many hardware players were built around, so compatibility is about as good as it gets for legacy devices.

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