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Video frames do not scale properly

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In Firefox video frames don't scale properly. This affects both HTML5 videos e.g. youtube.com and Flash videos e.g. twitch.tv. When switching to Cinema view in youtube, or closing the side panels in twitch, the frame will extend to the left and right, leaving black bars at the side, but the video does not scale and the frame does not increase in height. I don't have the issue in Safe Mode and also not in Chrome. However I still have the issue in Firefox with all extensions disabled. I tried to delete cookies, cache and refresh Firefox, but the issue still exists. I also tried to disable Hardware acceleration in both the Flash Player and Firefox, but that also does not solve the issue.

In Firefox video frames don't scale properly. This affects both HTML5 videos e.g. youtube.com and Flash videos e.g. twitch.tv. When switching to Cinema view in youtube, or closing the side panels in twitch, the frame will extend to the left and right, leaving black bars at the side, but the video does not scale and the frame does not increase in height. I don't have the issue in Safe Mode and also not in Chrome. However I still have the issue in Firefox with all extensions disabled. I tried to delete cookies, cache and refresh Firefox, but the issue still exists. I also tried to disable Hardware acceleration in both the Flash Player and Firefox, but that also does not solve the issue.

Réiteach roghnaithe

Safe Mode also deactivates userChrome.css and userContent.css. If you have created either of those files to customize Firefox, you might check whether those rules affect video sites.

Oh, hold on, the problem continues even after you used the Refresh feature? That would have removed those customizations. (I'm assuming you tested before reverting to older settings.)

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check this:

  • see if there are updates for your graphics drive drivers

https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration

  • disable protected mode in the Flash plugin (Flash 11.3+ on Windows Vista and later)

https://forums.adobe.com/message/4468493#TemporaryWorkaround

  • disable hardware acceleration in the Flash plugin

https://forums.adobe.com/thread/891337 See also:

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Réiteach Roghnaithe

Safe Mode also deactivates userChrome.css and userContent.css. If you have created either of those files to customize Firefox, you might check whether those rules affect video sites.

Oh, hold on, the problem continues even after you used the Refresh feature? That would have removed those customizations. (I'm assuming you tested before reverting to older settings.)