Experiencing problems playing movies d/l from itunes store

Downloaded a batch of HD movies recently. They've all completed downloading, but whenever I try to play any of them a lot of times I will be greeted with a blank screen for several minutes before the movie starts playing. Sometimes the movies don't play at all. Sometimes they do play relatively well. And even other times I will be prompted that my computer or TV is not HDCP compatible, which makes no sense because the movies actually plat sometimes.

Any idea what this issue is and how to fix it? It's not just on my PC but on my macbook too, so I know its an itunes issue.