Apple iPhone iOS 5.1 - Manual (Page 129)

Converting videos for iPhone
You can add videos other than those purchased from the iTunes Store to iPhone, such as videos
you create in iMovie on a Mac, or videos you download from the Internet and then add to iTunes.
If you try to add a video from iTunes to iPhone and a message says the video can’t play on iPhone,
you can convert the video.
Convert a video to work with iPhone: Select the video in your iTunes library and choose
Advanced > “Create iPod or iPhone Version.” Then add the converted video to iPhone.
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