Citrus, I knew some of that ^^^ Or at least something like that. There used to be a flashing circle or something in the corner on movies, indicating it was soon time to change the reel. I also remember there were two stripes, smaller than the square in the vid you posted, and I always used to watch out for it. I think that was a similar thing whereby it showed the commercial break was on its way

Happy Hour by The Housemartins (with a line-up of Paul Heaton later from The Beautiful South and Norman Cook, later to become Fatboy Slim) is an excellent, excellent song that has to have a place on this thread. The video is worthy of nearly 3 minutes of anyone's time, and both song and video take me back to some very happy times in my life Love it!

Happy Talking by Captain Sensible is another that brings with it great memories!

Happy talking talking happy talk
Talk about things you'd like to do
You've got to have a dream
If you don't have a dream
How ya gonna have a dream come true?