Video

What is an AVI file?

Updated Jul 2026

Definition

AVI (Audio Video Interleave) is a video container format Microsoft introduced for Windows in the early 1990s. It bundles video and audio into one file, often without much compression, so quality stays high but file sizes get large. Many modern devices and apps, especially on Mac and mobile, don't play it without converting first.

AVIAudio Video Interleave

Extension: .avi
Type: Video
Typically: Legacy Windows video

Why AVI exists

Microsoft built AVI in 1992 as part of its early multimedia push for Windows. It was one of the first formats that let a single file hold both a video track and an audio track together, which is where the name comes from: the audio and video data are interleaved in alternating chunks.

AVI itself is just a container, a wrapper that can hold video encoded in different ways. Older AVI files often use little to no compression, which is why they look clean but take up so much space. Newer ones might use a modern codec inside that same old container, with mixed results depending on what's reading the file.

People run into AVI today mostly through old camcorder footage, screen recordings, or files downloaded from Windows-era software and hardware. The format plays natively on Windows but is spotty on Mac, iPhone, and many web apps, so it usually needs converting before it uploads or plays anywhere else.

The trade-offs

Strengths

Can store video with little to no quality loss
Simple, well-documented format that's been stable for decades
Still plays natively on most Windows machines

Watch-outs

Files are often far larger than newer formats for the same footage
Not supported by default on Mac, iPhone, and most web platforms
What's inside the container varies, so playback isn't guaranteed even on devices that claim support

A note on privacy

AVI files don't typically carry the kind of location or device metadata that photo formats do, but they can still include creation dates, camera or software info, and sometimes embedded subtitle or chapter data. Uploading one to an online converter means that footage sits on someone else's server while it processes. Converting on your own machine keeps the video, and whatever it contains, on your computer the whole time.

Convert an AVI file

Questions

How do I open an AVI file?

Windows plays most AVI files natively through its built-in apps. On Mac or mobile, you'll usually need to convert it to MP4 first, since native support is limited or inconsistent.

Is AVI better than MP4?

For raw quality and simplicity, AVI can hold video with less compression. For everything else, no: MP4 is smaller, plays almost everywhere, and is the format most modern devices and apps expect.

Why do my old videos save as AVI?

Older camcorders, screen recorders, and Windows software often default to AVI because it was the standard container for decades before MP4 took over.

Can I convert AVI without uploading it?

Yes. A desktop app like Morphjet converts AVI to MP4 or other formats directly on your computer, so the footage never has to leave your machine.

Morphjet opens and converts AVI and 1,800+ other formats, all on your own computer. Launching this July.