Problem with YouTube viewing size on rMBP 15"

I've had this problem ever since I got my rMBP 15" in 2012 where I'll initially be able to watch a YouTube video in the largest player size after starting Safari, but if I open a new tab, close the window and reopen another one or do something similar, it will default back to the smaller viewing size until I quit Safari and restart it. I'm not changing the width of the Safari browser and the largest size continuously works on my iMac. I've attached pics to show what I'm talking about.
Is there a fix for this? I've tried joining YouTube's HTML5 program, but that hasn't solved the problem.

Any help is appreciated. Thanks.

The "largest" size.


The smaller, yet larger player from the options.

walkie said:

This doesn't have anything to do with your rMBP, this is something about your web browser.

Click to expand...

Is it? This problem doesn't occur on my iMac when using Safari and this also happens when I use Chrome on my rMBP.

jont-fu said:

You might want to try out the Youtube5 extension for Safari, as it has a nice "popup" player button which I think is just the right size.

Unfortunately it now only works up to 720p but for me that's enough.

Additionally you might benefit from having less cpu strain (it plays hardware accelerated h.264 video) and get rid of ads.

Click to expand...

Thanks for the suggestion. I've tried this in the past, but I didn't like using it.