I have two use cases.
1st is a TV with ATV connected via a HDMI switch with audio going to a receiver. The TV is a DVI interface. When I stop using this setup I do not turn off or Sleep the ATV. I just switch off the TV and the Receiver. When I turn it back on, whatever channel was playing is still playing. (ATV Does not Sleep) - So, no problem
Problem:
2nd use case is a TV connected to ATV via HDMI where the ATV tells the TV to power off when ATV is commanded to "Sleep" by holding the TV icon button. Any tough of the remote after that will power up the TV.
If the ATV is put into Sleep (with TV commanded off, but also likely when a TV is not commanded) and Channels is active and playing a channel the ATV will sleep. After a period of time, that I have not measured, when the ATV is activated from sleep by touching a button on the ATV Remote, the Channels App is frozen as a still picture on the screen that was likely previously playing when Sleep was activated. This or, I have seen the same screen with a gold triangle stating the Tuner Cannot Be Found or sometimes an all black screen with nothing At this point the only option is to click the Menu button to back out. When you do this all of the Channels icons are blank with no data. You can select a channel and it will then play, but f you back out again the channel icons are still blank. If you go up another level, and then back into the app, or where you were, it appears the icons are refreshed.
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It would be nice if the App could detect the sleep state or the wake state to automatically reinitiate the stream that was playing when Sleep was activated. It would also be good if the channel data could be refreshed automatically in the background after waking from sleep when Channels is the active App. I dont know if any of this is possible based on what Apple provides in its APIs, but it would improve the consistency of the user experience and overall quality of the app.