I have 64 bit Windows 7 computer with a HD7870 video card. I've installed the latest Quicktime update and checked both Adobe & Windows for the latest updates and installed where necessary.
When attempting to preview a transition from the list of available transitions, when I hit play I am presented with 3 black bars across the the small preview screen, rendering the transition unwatchable.
Any clues on what might be causing this and how to fix it?