Audio Output changes from HDMI

[Westyfield2]

I use the HDMI output on my 2012 Mac Mini for both Audio and Video.

Sometimes when I change the TV to the Mac Mini's HDMI input port (instead of the ports that the Blu-Ray, Satellite, etc are plugged in to) I find that the Mac Mini has changed its Audio Output from being HDMI to being one of the other options (internal speaker/headphone jack/soundflower). The same sometimes happens when I turn the TV on after having been off.

This however does not happen every time I switch HDMI input on the TV.

I guess what's happening is that when the TV is on another HDMI input port (Blu-Ray, Satellite, etc) or turned off, the Mac Mini can no longer see that the TV exists. The Mac Mini then things that it is being helpful, and changes its audio output setting to something that does exist (internal speaker/headphone jack/soundflower). It however does not then revert the setting when the TV comes back into existence.

I guess what I need to do is either:

1. Tell the Mac Mini to continue sending Audio out of the HDMI port regardless of whether it thinks there is any device plugged into it or not (i.e. never change output by itself)
2. Have the Mac Mini change the Audio Output back to HDMI automatically when the TV comes back into existence after having changed to internal speaker/headphone jack/soundflower when the TV disappeared

Any ideas?