Video problems in FF-nightly

[AN]

Has anyone noticed problems with video in FF-nightly recently?  In the 
last few days I am having a problem watching videos in FF-nightly.  The 
problem is that the audio plays fine, but the video freezes.  This happens 
with both Flash and HTML5 videos.  Both had been working previously.

I have not changed any of my options for compilation.  Is there some 
change in the source that may have caused this problem?  I see the problem 
on FreeBSD-current with FF-nightly, and also in a VBox VM running 
opensuse11.4 and FF-nightly.  Both were working fine until about 2 days 
ago.