Upgraded to 11.10 and No Sound working on Firefox

[Doctorj]

I have just upgraded from 11.04 to Kubuntu 11.10. When I look at a video in a web page in Firefox I have no sound. I think there might be some third party files I have to install but I cannot remember what they might be. Can anyone suggest to me how to get that sound working again?

Thanks
Doctorj
++