Buffers the video without autoplaying and puts it in HD if the option is on. For Firefox, Opera, & Chrome
< Feedback on YouTube Auto Buffer & Auto HD
May I ask why you're clearing your cookies so often? I don't like to add a lot of options unless they're really good ideas or necessary.
I clean them often because I do a bit of HTML and Java dev and sometimes clearing the cache fixes some problems, also to force logout from all the accounts I'm logged in, oh and to get Youtube's default "What to watch" videos (without their suggestions that I never like). If you can't do it for this script then I suggest it for other maybe? If you do it I feel it would certainly be a cool feature. But anyways Youtube may simply change the player soon so it may not be worth it.
I don't feel like it fits into this script, but if I could find the aforementioned cookie, I could certainly make you a separate script.
The cookie is named "PREF", the contents are:
Normal player: f4=4000000&f5=30&f1=10000000
Transparent player: f1=10000000&f4=4000000&f5=20030
In case you feel like making the script.
Feature request for transparent player
Can you add an option to enable/disable the transparent player? Right now I have to enable it from ( https://www.youtube.com/testtube ) everytime I clean my cookies. I believe it's just a setting you add to the cookie but I don't know if it's doable.