iTunes U supports the distribution of compressed audio and video files. Apple recommends using the following formats for your iTunes U audio and video content:
Audio files (AAC, MP3) with appropriate file extensions (.m4a, .mp3). For best results during playback, Apple recommends converting MP3 files greater than 32 megabytes (MB) to AAC format. For AAC audio files, Apple recommends the following specifications:
Audio Format: Baseline Low-Complexity Profile with AAC-LC (Music)
Data Rate: Up to 160 Kbps
Channels: Stereo in .m4v, .mp4, and .mov formats
Output Sample Rate: 48 kHz
Encoding Quality: Better
Video files (MPEG-4 with H.264 compression) with appropriate file extensions (.mp4, .m4v, .mov). For best results with iPod, Apple recommends using MPEG-4 with H.264 compression with the following specifications:
Video Format: MPEG-4 with H.264
Data Rate: Up to 1.5 Mbps
Image Size: 640 x 480 pixels
Frame Rate: 30 frames per second
Key Frame: Every 24 frames
Audio Tracks: Baseline Low-Complexity Profile with AAC-LC audio up to 160 Kbps
You can also use iTunes U to distribute Portable Document Format (PDF) and electronic publication (ePub) files. ePub files must pass ePubCheck 1.0.5, include only files listed in the manifest, and use UTF-8/16 characters. For more details, read the complete ePub specification at http://www.idpf.org/specs.htm. PDF and ePub files appear in iTunes U and the iTunes U library with a book icon. To open a PDF or ePub file, download the file and double-click the file. iBooks or another reader is required (download the free iBooks application from the App store). You cannot preview a PDF or ePub file in iTunes U.
iTunes U supports images embedded in tracks in JPEG, PNG, or GIF format with appropriate file extensions (.jpg, .jpeg, .png, .gif) in RGB Color Model. JPEG images can include EXIF or JFIF, but not both.
If you host your content on a server using an SSL URL scheme (https), be sure to set up a valid certificate. If iTunes U cannot obtain a verifiable certificate the request fails. If you cannot set up a valid certificate, switch your content to a server using a non-SSL URL scheme.
If you are using QuickTime to create and edit video content, Apple recommends that you export your videos by choosing “Movie to iPod” from the Export pop-up menu in QuickTime Pro. For more information, see http://www.apple.com/quicktime/.
Some MP3 audio files, specifically ID3 version 1.x tagged files, have known issues displaying track artwork information. To use specific artwork with these audio files, Apple recommends either converting the files to MP3 files tagged as ID3 version 2.4 or converting the files to the AAC file type format (.m4a).
iTunes U does not support the downloading of WAV or AIFF file formats on the iPod, iPhone, or iPad.
Due to video file profile level requirements, iTunes U might not play some files on the iPad without re-encoding the files. For more information, see the iPad audio playback and TV and video requirements at http://www.apple.com/ipad/specs/.
© 2011 Apple Inc. All Rights Reserved. (Last updated: 2011-11-03)