I'm not sure if anyone can help with this (nobody else I've asked can!) but I've somehow created a really odd video effect. Here's a sample still from a DVD, where you can see that half the frame is lit by a camera flash, and half isn't!

venb.jpg

I count 36 'layers' which would give 16 lines per layer, at the normal DVD resolution. The effect is visible in camera flashes as here, or at any point where the camera pans.

The video was edited in iMovie, where the effect first appeared. All the source files were OK before editing, so I guess I must have set something up wrongly in iMovie. Although I've done a bit of work with video in the analogue days this was my first try at digital and I hope it won't be my last!

Thanks for your attention.