If you’ve come across a file ending in .avi and aren’t sure what to do with it, you’re not alone. AVI files are a common video format, especially in older recordings or downloads. Whether you’re using Windows, macOS, or a mobile device, this guide will explain what an AVI file is, how it works, and how you can open or convert it.

What Is an AVI File?

AVI stands for Audio Video Interleave. It’s a video file format developed by Microsoft back in 1992. An AVI file is a type of container format, which means it can hold both video and audio data in a single file — often compressed using different codecs.

Unlike modern formats such as MP4, AVI doesn’t always compress data as efficiently. As a result, AVI files can be quite large, but they maintain relatively high quality.

How Do AVI Files Work?

An AVI file combines audio and video streams. It doesn’t define how those streams are encoded — that’s what the codec does. Common codecs found in AVI files include:

• DivX
• Xvid
• MJPEG
• MP3 or AC3 (for audio)

Because AVI is just the container, two AVI files might behave very differently depending on the codec used inside. That’s why some AVI files won’t play unless your device has the right software to decode them.

How to Open AVI Files on Windows

Most Windows users can open AVI files using Windows Media Player, especially on Windows 10 and 11. However, some AVI files may not play correctly if the required codec is missing.

For full compatibility, it’s recommended to use VLC Media Player:

• Download VLC from videolan.org
• Install and launch VLC
• Drag and drop the AVI file into VLC, or right-click the file > Open With > VLC

VLC supports almost all video and audio codecs without needing extra downloads.

How to Open AVI Files on Mac

On macOS, QuickTime may struggle with AVI files due to missing codec support. In most cases, the best solution is again VLC Media Player for Mac.

Other options include:

• Elmedia Player
• IINA
• MPlayerX

These players are designed to handle a wider range of formats than QuickTime.

Can You Open AVI Files on Mobile Devices?

Yes, but native players on Android and iOS don’t always support AVI playback smoothly — especially if the codec inside the AVI file is uncommon.

Recommended mobile apps:

• VLC for Android/iOS
• MX Player (Android only)
• Infuse (iOS, Apple TV)

These apps offer broader codec support and allow you to stream, browse, or play files directly from local storage or the cloud.

Best Free Software to Open AVI Files

If you’re looking for versatile tools that open AVI files across platforms, these are some of the best free options:

• VLC Media Player (cross-platform)
• KMPlayer (Windows/macOS)
• PotPlayer (Windows)
• Elmedia Player (macOS)

All of these can handle most AVI files without extra setup.

How to Convert AVI to Other Formats

If a certain AVI file won’t play or is too large, converting it can help. The most common conversion is to MP4, which is smaller and more compatible.

Popular free converters include:

• HandBrake (Windows, macOS, Linux)
• Any Video Converter
• Freemake Video Converter

Steps in HandBrake:

1. Open the AVI file
2. Set the output format to MP4
3. Choose a preset (e.g., Fast 1080p)
4. Click Start Encode

This will produce a smaller, easier-to-play version of the original video.

AVI vs MP4: Which One Should You Use?

AVI Pros:

• High video quality
• Good for editing
• Works well on older systems

AVI Cons:

• Large file size
• Not web-friendly
• Compatibility issues with some players

MP4 Pros:

• Smaller file size
• Excellent device compatibility
• Better for online sharing and streaming

If you don’t need AVI for a specific purpose, MP4 is the better all-around format.

Conclusion

An AVI file is a legacy video format created by Microsoft, designed to store both video and audio in a single container. While it’s less common today than formats like MP4, AVI files are still widely used in older archives, security camera footage, and some video editing workflows.

To open an AVI file, the best option is VLC Media Player, which works on nearly all platforms. If you have trouble playing or sharing the file, converting it to MP4 is a smart move.

Now that you know what AVI is and how it works, you can handle these files with confidence—whether you want to play, edit, or convert them.