If you attempt to import your AVI files to iTunes (iTunes 12.1), and possibly sync them to your iDevices later, you are not going to get what you want. This is due to iTunes' incompatibility with AVI files. Any videos you try to add to iTunes need to be encoded with H.264 and wrapped up in MP4, MOV or M4V file container. In one word, AVI video files are not supported by iTunes. Fortunately, you simply need an AVI to iTunes Converter to convert AVI video to iTunes-friendly format. Here is a step-by-step guide to convert and import AVI to iTunes on Mac OS X Yosemite, Mavericks with the help of Brorsoft Video Converter for Mac.
It is specially designed for Mac OS X (Yosemite, Mavericks) and can easily convert AVI to iTunes (iTunes 12) supported MP4, MOV, M4V format in a lossless way. In this way, you can transfer AVI files to iPhone, iPad, iPod and Apple TV via iTunes without any hassle. What’s more, Brorsoft Video Converter for Mac is built with a video editor, which lets you touch up the video as you like. If you are Windows users please turn to Brorsoft Video Converter. Now download the program and follow the full guide.
Read More: AVI to iPad Air | AVI to Apple TV | AVI to Final Cut Pro
How to convert AVI files to iTunes on Mac
Step 1. Add AVI files
Launch Brorsoft Video Converter for Mac and simply drag-and-drop your AVI file to the program or click Add button to load AVI videos. You can add multiple files at a time an convert them in batch.

Tip: This AVI to iTunes converter Mac allows for customizing subtitle. If you wanna keep your original subtitle or add new, you can click on “Edit” button, the video editor will pop up. Tap “Subtitle” option and check the “Enable” icon. Then, by clicking on “Browse” to import your *.srt, *.ass, *.ssa subtitle file you’ve downloaded. See how to add subtitles to AVI.
Step 2. Select iTunes compatible format
Since iTunes supports MP4, M4V and MOV formats, you can click Format bar and choose any of the three from Common Video as the output file format.

Tip: If you eventually want to sync AVI to iPhone, iPad, iPod via iTunes, you can select your device model from an array of presets and the program will set the optimum resolution, bit rates, codecs, and other parameters without your say-so.

Step 3. Start conversion
After you coming through the steps above, simply click the Convert button to begin converting AVI files to iTunes on Mac. The conversion will be finish in a few minutes.
When the conversion is complete, get the resulted files by clicking the Open button. You can now add the converted AVI files to iTunes easily. Afterwards, you can even freely transfer your favorite AVI movies to iPhone, iPad, Apple TV, etc. via iTunes.
Additional Tips:
For those who are attempting to add your DVD/Blu-ray movies as well as downloaded videos files in .mkv, .wmv. .flv, .vob, .mpg format to iTunes on Mac, the all-in-one iMedia Converter for Mac program will be a better choice.
Additional Tips - If you have any problems importing, editing or playing AVI files on your Mac or PC, please enter "AVI Related Guides & Tips" to find the solutions.
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Source: How to convert AVI to iTunes free on Mac