Convert MP4 to AVI With Xvid Video for Older Players and Editors

What changes when you convert MP4 to AVI

MP4 and AVI are both containers: boxes that hold a video stream, an audio stream and some metadata. What differs is which codecs each one usually carries and which software still reads it. MP4 (MPEG-4 Part 14) is the modern ISO container that phones, cameras and streaming services use, normally with H.264 or H.265 inside. AVI (Audio Video Interleave) is Microsoft's RIFF-based container from 1992, and the software that still asks for it expects older, simpler codecs.

That's why this MP4 to AVI converter doesn't just rename the file. It re-encodes the video to MPEG-4 Part 2, the Xvid and DivX-era codec, and tags it with the "xvid" FourCC code that old players look for. The audio becomes MP3. I picked that pairing on purpose. An AVI with H.264 inside is technically valid, but the old software people convert to AVI for usually can't decode H.264 either, so it would defeat the point.

Who still needs MP4 to AVI conversion

Nobody picks AVI because it's the better format. An MP4 is smaller at the same quality. People convert because one specific program or device in their workflow only accepts AVI:

• Older video editors. Editing programs from the DVD and early HD years, and plenty of niche or industrial software still in daily use, were built around AVI import before MP4 took over.
• DVD authoring tools. Many DVD burning and menu programs expect AVI or MPEG sources, not an MP4 with H.264 or H.265 inside.
• Older and embedded players. Standalone media players, digital signage boxes, older smart TVs and car or factory displays often support only AVI-era codecs and refuse a modern MP4.
• School, work or archive rules. Some institutions still require AVI for submissions because their systems were set up around it years ago.

In each case the goal is a file that one particular, often old, program or device will open without an error.

How to convert MP4 to AVI

The encoding runs through FFmpeg compiled to WebAssembly, because no browser ships an MPEG-4 Part 2 encoder of its own. The first conversion in a browser downloads the encoder once and caches it.

You won't see a preview of the AVI on the page. Chrome, Firefox and Safari can't play MPEG-4 Part 2 video, so a preview would only show a black box. The file itself is complete. Open it in the player, editor or device you converted it for.

Why this MP4 to AVI converter is free

Many "free" MP4 to AVI converters are really trials. You get a watermark across the video, one or two conversions before a paywall, or a size cap that pushes anything longer than a few minutes onto a paid plan. I didn't build any of that into this one.

The AVI you download carries no watermark, logo or timestamp, just your footage in a new format. You can convert one MP4 or a hundred without an account, and there's no daily cap or "Pro" tier. I don't cap file size or length either. A two-minute clip and a two-hour recording go through the same way. The long one just takes your device longer to encode.

I can offer that because nothing is uploaded. No server does the encoding, so a conversion costs me nothing to run and there's no reason for a paywall. Your processor does the work, the same as desktop software would, without the install.

AVI vs. MOV, MKV and WebM

AVI isn't the only alternative container. Here's how it compares with the others you're likely to run into:

If the video is headed for a browser or a web player, WebM is the better target, and the MP4 to WebM converter does that directly. Choose AVI when something you don't control, like an editor, a device or a submission rule, asks for it by name. And if the MP4 is simply too big, the video compressor shrinks it without changing the format.

Frequently asked questions