[ubuntu] Embedded video and captchas not showing in Firefox

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http://ubuntuforums.org – I can play video on the youtube website, but I cannot play youtube videos embedded in facebook or other websites. Captchas are also not showing up, I suspect the two problems are really the same problem. This started about a week or two ago. No such problems are present when using Chromium. I already tried uninstalling and reinstalling firefox. (Hardware)