My kids have a tendency to turn on the tv and then leave, on our previous TV we used a Chromecast (streaming only) and then Home Assistant to monitor if the TV was on and the Chromecast paused for more than 15 minutes, if so the TV was turned off.
On our new TV, Samsung Q70R, we use Samsungs smart-tv hub instead of the Chromecast. It seems like Samsung only sends if it is turned on or off, but not what is playing. Can this somehow be extracted?
Have a look at the developer tools / states menu and look at the attributes of your tv media player when it is playing or paused.
The only entry there is unfortunately the TVs on/off status. The playing/pause information that the Chromecast sends is not available for the TV itself.
Wow, really no source attributes or anything?
If I go to the attributes (currently streaming youtube), the source attributes are:
source_list: TV, HDMI
is_volume_muted: false
friendly_name: Stue Q70R
supported_features: 20281
device_class: tv
So that seems pretty basic?
Someone else has just posted the same issue for a different tv.
Looks like you are out of luck unless someone further develops the available attributes.
Did you use the standard Samsung integration? There are 2 or more custom Samsung smart TV integration through Hacs, these will give you more, I afraid the only real way will be to link your TV with smartthings and then use the Samsung smart TV component from the hacs.
Yes I just used the standard integration. Thanks for the heads up regarding HACS, I will have a look there.
Did you have any success with this? I have a Q60B and same issues, no states except for on and off 
No unfortunately not - mine is still hit or miss with no apparent pattern in when it works or not. “Fortunately” we now use an Apple TV as streaming device, which works reliably in HA, so my automations now uses ATV status instead. But still that is not ideal if other inputs than ATV is used.