GoodPlayer is a very versatile media player for iOS, it was one of the first iOS aps that supported WTV and MVK files and will play a wide range formats. It plays videos stored on your device via iTunes File Sharing or Wi-Fi but until now it could not play content from the iPod library on the device. iPod library support has just been added to the app so you can play music and video from stored on the device as well as the file sharing and Wi-Fi options.
If you want a media play that will play just about any format and supports TV Output and HDMI you should check out the app. It costs £1.99 from the iTunes Store.