Woah I wasn't aware of that, is it possible to change Youtube back from HTML to Flash?
Well, in order to do that, you'd have had to change it to HTML5 in the first place. If you didn't install an extension to do that then you should already be on Flash.
An easy way to find out is simply easy and simple..
Open a YouTube video, anything popular or recent, and right click on it. If you get a normal system menu with an option at the bottom that says "About Flash ..." then you're using Flash. If you get a smaller plain white with black text menu with the option at the bottom saying "About the HTML 5 Player" or something of the like, then it's HTML5.
If you have Flash and are still having that problem, then it's a mystery.
But if you determine you are using HTML5,
which is so much better for your machine and less intensive on the CPU and memory and I wouldn't recommend switching away from in a million years because HTML5 is so much more superior, then you can just open Preferences and go to Extensions and disable whichever HTML5 YouTube extension you are using. Command+, will open Preferences quickly if you want.
The loss of 1080p and 480p options for me are nothing compared to the feeling of not having to use Flash for YouTube. Especially on OS X where the video player actually puts itself into a "Lion Fullscreen" space when you go fullscreen as opposed to Flash which covers up your browser and makes you unable to do other things at the same time. It's a godsend when you use two displays too.
They're in Yosemite's Safari build.
Oh. Well would you look at that! 1080p is an option for YouTube Center. I didn't even realize that! I guess I had gotten so used to just watching the content and was so used to Yosemite that I didn't even notice the change or that I had a 1080p option.
Hey, Jo Shishido's Cheeks, there's your solution. When you switch to Yosemite in the fall, install YouTube Center. It gives you HTML5 video but allows you to use any resolution you want. (Except 480p which as I said is completely silly in every aspect.) For now just use Flash or live without 1080p.
And Youtube isn't likely to stop fighting it, as constantly breaking downloading tools is what they tell rights holders their DRM is, instead of using actual DRM.
And I thank them for it. Occasionally I want to download a YT video. Though what you're saying doesn't make sense as the download button rarely breaks. It always works. It's the playing API itself that changes constantly and breaks all the extensions that make YouTube easier to use. Downloading however never stops working because it's a URL to a video file that could only break if they changed the save location. However, other player features that extensions like to add, like disabling autoplay (A feature that every fucking video player SHOULD HAVE GODDAMMIT) occasionally stops working or other small features like resizing the default player, etc, like to occasionally break when YouTube makes API changes.