For some unknown reason, MythTV changes MPEG decoder to 'Standard' (ffmpeg). This starts using the CPU instead of the GPU for rendering. That leads to slow response to remote control and high speed for CPU fan during live/playback of HD content. When I reset it to 'XVMC' things are bettter. So, I want to set MPEG decoder to XVMC whenever mythtv exits.
I found a work around using 'Application Exited' event on myth. But, still would like to know why 'deveice turned on or of' didn't work.