Help! I'm not longer able to download trailers in iTunes.

This seems like a new issue, unrelated to when Apple briefly removed the download option on trailers last summer. I like to download and maintain a collection of all the trailers I like. However, going back to about the fall of 2013 I am no longer able to download any new ones. For example, when I go to download the new Captain America 2 - iTunes will download, the file will have a file size of 200+mb, but when I go to play in iTunes (or the original file in QT Pro) there won't be any picture or audio - though the timeline scroll will move like it's playing. Older trailers I've downloaded like Avatar, etc still play fine. This applies to both the 720p and 1080p downloads. I've tried uninstalling iTunes and re-installing to no avail. Any advice would be greatly appreciated! Thank you!