Tvheadend

Hi,
i am distrubuting some FTA channel via transcoding and openvpn to a friend.
Hence my internet connection has only 4mbit upstream, i have to use the transcoder.

Just a few words to my setup :)
4 Satelites -> multi switch -> satoverip (digibit r1) -> lan ->
tvheadend@vmware_esxi -> pfsense@vmware_esxi -> openvpn -> internet ->
friend -> accesspoint@openwrt_openvpn -> firetv_stick

Everything is working well.
The transcoding demands quite much cpu-load, respectively electricity (=money).
On the other end, my friend leaves sometimes his kodi@firetv stick running, and so the CPU of my server has to run the
whole days sometimes for nothing.

Question:
A powersave script, which just disconnects/interrupts the stream to the client,
if for more than a specific time (1h), no channel has been changed.

I am running the a quite current edition, hence self-compiled.
OS is ubuntu server 15.x.