A strange problem manifested on my machine recently, and I'm really at a loss when trying to resolve it, as I don't even know how to google this.

I was watching Netflix full-screen one fine day, on Firefox v64.0, on my Ubuntu 18.04.1 laptop. At some point, I thought I saw ghost images overlaid on my video. I thought my eyes were just tired and paid no attention to it, I closed the laptop and went to get some coffee.

Later on, while watching a YouTube video (again, fullscreen) and I thought I saw the ghost image again. I turned up my screen's brightness all the way to 100% and lo-and-behold, I could see my wallpaper through the full-screen video!

This has been going on for some days now, and I wasn't able to find what's causing it. Full screen videos on Netflix and YouTube have some sort of 10-20% transparency, and I can see my wallpaper behind them. This only happens when the video is playing. When I pause the video, transparency goes away. You can understand how this played with my mind a little bit at first.

Local video files on my machine, played through mpv, have no transparency issues.

To give you an example, I'm sorry but I literally took a photo of my laptop's monitor.

Here's a full screen YouTube video of a pure black screen, for 10 hours (It's just a video of all-black playback):


The image in the back (the ghost image I was seeing) is of course, nothing else other than my wallpaper:

enter image description here

The transparency is also captured in regular screenshots. Here's one of the above 100%-black-video fullscreened and playing. It isn't as visible because it's a software screenshot, but you can see the ghost image there too if you squint.

enter image description here

  • 2
    I really hope I'm not really losing my mind... Dec 16, 2018 at 22:25

2 Answers 2


My config is Firefox 64.0, Ubuntu 18.04.1. Experienced the same problem. After searching and reading, finally was able to fix it.

Changed layers.acceleration.force-enabled option to true in the about:config

Edit: You may also try to create mozilla.widget.use-argb-visuals as Boolean and set it to false in about:config

Source: Firefox Bug 1516224 Semi-Transparent YouTube video playback

  • Thank you, this worked. May I ask how you searched for it? What did you look for? Source on what was causing this? Dec 20, 2018 at 12:40
  • Searched for something like "ubuntu firefox fullscreen video transparent" and found this askubuntu.com/questions/1100753/…
    – Evgeny
    Dec 21, 2018 at 2:20
  • This did fix the issue but caused other rendering issues for me Jan 22, 2019 at 17:15

In about:config setting gfx.xrender.enabled to true fixed it for me, with no rendering issues and no loss of performance.

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