What format are the videos you are trying to play? Can you please tell us what websites this occurs on? Do the videos play if you download them and try and open them with Totem?
** Changed in: firefox (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to firefox in Ubuntu. https://bugs.launchpad.net/bugs/831598 Title: Some videos won't play. All I get is a blank black screen. Status in “firefox” package in Ubuntu: Incomplete Bug description: I have had this problem with several videos. The links take me to the video's, but there is nothing but a blank black screen, and no way to play to video. ProblemType: Bug DistroRelease: Ubuntu 11.04 Package: firefox 6.0+build1+nobinonly-0ubuntu0.11.04.1 ProcVersionSignature: Ubuntu 2.6.38-11.48-generic 2.6.38.8 Uname: Linux 2.6.38-11-generic x86_64 NonfreeKernelModules: nvidia Architecture: amd64 Date: Mon Aug 22 15:59:01 2011 FirefoxPackages: firefox 6.0+build1+nobinonly-0ubuntu0.11.04.1 flashplugin-installer 10.3.183.4ubuntu0.11.04.1 adobe-flashplugin N/A icedtea-plugin 1.1.1-0ubuntu1~11.04.1 InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release amd64 (20110427.1) ProcEnviron: LANGUAGE=en_US:en LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: firefox UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/firefox/+bug/831598/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp