Here's the net result of another round of YouTube frustration. I feel guilty now, and more than a little dirty that I persisted so much in trying to find a solution for the compression artifact problem this user was having, when the simpler solution was known to me. But I suppose I did persist in part because when I recommend Vimeo instead, I'm usually faced with the statement, "But YouTube is where all the viewers are!"
Sure they have that huge audience. But so much of the video is damaged, and one has to wonder, why persist at trying to address the problems when there is practically no transparency, and much of the guidance on rendering for YouTube, at least in the official "support" pages, is insufficient, or even (frequently) dead wrong? Well, at least this latest head-scraper made me go back and look at where the good videos are.
When YouTube manages to do this, I'll start to think they mean something about quality. Granted, you could probably do it in an embedded player? Not sure I really want to go to the trouble to test it, though, when I do have many other more pressing issues to deal with.
For more "tall" videos, see the Vimeo ||tallscreen group.