iMac Flickering in Youtube videos on Firefox

I Need a Drink

macrumors regular
Original poster
Oct 14, 2013
181
32
I have a 2013 27" iMac and when I watch youtube videos, using Firefox, the control areas (top and bottom) of the youtube video flicker when I watch. This primarily happens at the top and bottom of the video where the controls and video header are located and not the main video. If I let the controls fade away then there is no problem, but as soon as I move the mouse the flickering is there again. This does not happen on my other Macs or on other video sites, only youtube. It started on Sierra and continues on High Sierra. I have done a clean install and I have scanned with Malwarebytes, which found nothing, but it still continues. This is only on Firefox, Safari works fine, and I do not have Flash installed. Any thoughts?
 

Samuelsan2001

macrumors 604
Oct 24, 2013
7,682
2,103
I have a 2013 27" iMac and when I watch youtube videos, using Firefox, the control areas (top and bottom) of the youtube video flicker when I watch. This primarily happens at the top and bottom of the video where the controls and video header are located and not the main video. If I let the controls fade away then there is no problem, but as soon as I move the mouse the flickering is there again. This does not happen on my other Macs or on other video sites, only youtube. It started on Sierra and continues on High Sierra. I have done a clean install and I have scanned with Malwarebytes, which found nothing, but it still continues. This is only on Firefox, Safari works fine, and I do not have Flash installed. Any thoughts?
Use safari for you tube? It seems like a Firefox coding issue, if so, until they sort it out with an update there is nothing you can do.
 

I Need a Drink

macrumors regular
Original poster
Oct 14, 2013
181
32
Use safari for you tube? It seems like a Firefox coding issue, if so, until they sort it out with an update there is nothing you can do.
Don't thinks it's strictly a Firefox issue because I use it on my MBP and my Mini with no issue. Also, it's been going on for more than a year, so I don't see it getting fixed anytime soon.
 

boto

macrumors 6502
Jun 4, 2012
437
28
Do you use any extensions? I use to use Magic Actions on Chrome, but after removing it the video flickering went away as well as other issues.