the screenshot

What site and what is playing the video? Just by that is hard to know where and how it is doing that.

Is this with all websites/videos? Some, a few?

See if there are updates for your graphics drivers https://support.mozilla.org/en-US/kb/upgrade-graphics-drivers-use-hardware-acceleration

almost half of the videos on facebook and youtube ,i dont face this problem on other browsers §which means i think the drivers are ok , and firefox is up to date

First, let's make sure you are not blocking content.

Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

yeah thanks everything works fine using safe mode ,but what could cause the problem knowing that i have only 3 addons installed and only one is enabled which is adblock?

If everything is fine in Safe mode that means something else is installed is causing the problem and it isn't a FF problem. You should disable adblock and see what happens. I know some sites if you use blockers they will block your access in return.

It could be adblock or something else on your system.

Hi mohamed.pbuh,

If the problem does not exist in Safe Mode, and you get this green screen (shown in your screenshot) : try disabling graphics hardware acceleration in Firefox. Since this feature was added to Firefox it has gradually improved but there are still a few glitches.

You will need to restart Firefox for this to take effect so save all work first (e.g., mail you are composing, online documents you're editing, etc.,) and then perform these steps:

1. Click the menu button and select Options (Windows) or Preferences (Mac, Linux).
2. Select the General panel.
3. Under Performance, uncheck Use recommended performance settings. Additional settings will be displayed.

   

4. Uncheck Use hardware acceleration when available.
5. Close Firefox completely and then restart Firefox to see if the problem persists.

If the problem is resolved, you should check for updates for your graphics driver by following the steps mentioned in these Knowledge base articles:

• Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

• Upgrade your graphics drivers to use hardware acceleration and WebGL