It seems that sometimes when I upgrade my Abode Flash Player, both of my web browsers, Firefox and Chrome, seem to have their flash player's play obscure videos. In Chrome, the flash videos on Youtube are "fast-forwarded" and in Firefox, they are very choppy and unbearable to watch.
Try Fix 1:
System Settings > Sound > Hardware Tab > Profile > Select "Off" and then Turn it back to its previous setting.
Try Fix 2:
sudo apt-get install pavucontrol
And then run "PulseAudio Volume Control" and repeat the steps in "Fix 1".