background flashes and wrong speed

every time I open file it plays slow even when I change frame rate, eventually it speeds up but then background flashes in and out in between frames. Any help?

Verify if there are too many frames in your Timeline.

Hey, thanks for answering but not sure what you mean. There’s only 40 frames in timeline anyway, is there a limit to amount of frames? Sounds strange. Cheers.

I have the same problem. Let me explain it in detail. I have my movie at a 24fps rate. Ok, so I go to preview the movie. The movie goes down to a 12 fps rate. So what’s the fix for this? It completely screws up my lip sync, so please respond soon!