I don't have mplayer installed, but got the same problem, affecting, vlc, totem, and flash videos. the solution was to unselect my graphic card as an audio device, like Daniel's link says.
* ubuntu 12.04 64 uptdated ati 4850 without catalyst phenom 965 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1015910 Title: Video runs too fast and no sound To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/mplayer/+bug/1015910/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
