Help! Video Lagging - Latency

Hello, I’ve imported a short film into my cubase, I have it set at the same frame rate as the video, yet the video seems to be lagging, it’s as if it’s droppin frames. The audio is pretty much synced up but the video is glitchy and not smooth. I have tried everything I can think of so far (buffer, video format, video settings), I’ve tested it in Protools and the video does not lag in there. Any suggestions on what to check and try?

Thank you!

I sometimes get that when its an mp4. Try converting it to an uncompressed .mov