Without knowing the cause of the issue, I'm not sure how much I can help. It sounds to me like you're having touchscreen sensitivity problems.
There are a few things you can do:
1. Long press the video, choose Group Settings. Force an aspect ratio that is wide enough to create black bars above and below the video. This would move the cameras away from the top and bottom edges of the screen.
2. In UI3's main menu, choose UI Settings. Find the "Playback Controls: Extra Padding" option. It will make the buttons in the playback controls bar easier to hit.
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