Your example is not working but in digitizing old analog video this can happen. To fix it I have to post process the video to remove the last or first few scan lines. This is rarely if ever done once it goes up on youtube. It's not a bug and not a sign your hardware, software or drivers are defective.
Every time I watch a youtube video or any in flash, I get a flickering at the top of the screen. Is this a flash issue or a GPU issue?
I am using Chrome as a browser, I tried Firefox and it's worse I don't seem to have the issue in IE. It's only an issue in browser, I don't get the issue when playing videos on KODI or VLC
here's a example.

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