[Discuss] Colours gone "wonky" in latest update to Ubuntu 14.04

[Murray Strome]

When I play a video using vlc or any of the other movie players I have 
installed in Ubuntu 14.04 after the latest update, the colours have gone 
weird! I have seen this before several years ago, but don't know how it 
got fixed.  The colours are very much like they would appear on a TV 
using Component Video input with one of the cables (probably red) unplugged.

I rebooted into the Ubuntu 12.04 installation on the same computer (with 
all of the latest updates), and all the video players in it work OK on 
the same video files, so I know the video itself is OK.

Any suggestions as what might have gotten broken? Yes, I know that using 
a pre-release version is asking for strange things to happen!