I too had the purple / ping background after the latest firmware upgrade. The only way for me to fix it was:
Unplug the HDMI cable then plug it back in.
Go onto settings - Audio & Video - select video output HDMI - HDMI agan - Auto - on
I found these fixes to be a real pain. Prior to the upgrade I never had these issues.
Almost every movie I stream now freezes then I have to reboot the device and it will sometimes work for the rest of the movie or sometimes I have to reboot it again.
I had neither of these issues with the previous firemware. I have now reverted back and all is working great again.