the data type of media content (such as videos, docs, and images) is always going to be an array of Guid for the IDs of the items, even for a single item.
The best way I've found to do this is with a helper method that uses the API to retrieve that item by ID and then I can get the remaining data (url, title, etc).
For an example, take a look at this post: Retrieving Data From Dynamic Modules Using the Module Builder API
specifically the section Binding to Fields
Hope this is helpful!