Yes there are specific file formats for audio and video content. iTunes U supports the distribution of compressed audio and video files. As you consider which formats and file sizes to produce, keep in mind that your users will need to download the content from your site and that their bandwidth may vary. For longer-form video content, consider using a lower resolution or breaking the content into pieces.
Information on what formats iTunes U Public Site Manager supports is available from Apple at https://help.apple.com/itunesu/sitemanager/#/itu84755100-F911-4032-A959-A92907E17188.