Although the iPhone does not natively support playback of movies saved in the AVI format, you can still watch these videos on your phone with the help of third-party apps.
A wide range of free and paid video player apps provide the necessary infrastructure for playing AVI files so that you don’t need to go through the hassle of converting them to an iPhone-compatible format. Once you’ve settled on an app, transfer the videos to your iPhone using iTunes.
Tap the “App Store” icon on your iPhone’s home screen and search for alternative video players with support for AVI. As of June 2013, highly rated paid options include GPlayer, OPlayer HD, 8player and It’s Playing, while free options include PlayerXtreme, OPlayer HD Lite and 8player Lite.
Connect your iPhone to your computer using the standard iPhone USB cable, and then launch iTunes on the computer if it does not open automatically.
Click the “iPhone” option, and then select the “Apps” tab.
Select the alternative video player you installed on your iPhone from the File Sharing section.
Click the “Add” button, and then select the AVI file you want to put on your iPhone. The sync begins automatically and can take up to several minutes if the AVI file is large.
Click the “Eject” button when the file transfer is completed.
Launch the alternative video player app on your iPhone, and then tap your AVI file to begin playback from your device. Depending on the app you chose, you may need to navigate through some folders to find your video file.
Free apps can handle the basics of AVI video playback, but they lack many features found in the paid apps and often come with advertisements that are displayed at inopportune times. One prominent feature in each of the paid apps is the ability to access videos on a computer without a USB cable. If you have a large video collection on your computer, consider getting a paid app to have convenient access to your collection.
Information in this article applies to iPhones running iOS 6. It may vary slightly or significantly with other versions or products.