Display timeout on latest Chromecast

[JohnStrunk]

The current generation of "Chromecast with Google TV" seems to have a shorter timeout, so it returns to the screensaver if there is too much delay between races.

Workaround: disable then re-enable the Chromecast Enable "developer options" and set "Stay awake"

[JohnStrunk]

#231 didn't fix it.

The latest generation of Chromecasts seem to have a general issue w/ this... pending more investigation.

[JohnStrunk]

Opened a bug report against the Cast SDK related to the timeout issue: https://issuetracker.google.com/issues/282046056

Reopening this to track the above bug report. Current status of WR-specific efforts:

• Document configuration for Chromecast w/ Google TV #241 - Provides documentation on enabling "Stay awake" to prevent the timeout on CCw/GTV devices
• Custom Chromecast web receiver #252 - Tracks the effort to find a workaround via a custom receiver (so far, no luck)

[digilinCraig]

John, sorry if this is completely stupid (my background is not in python programming so perhaps there is some reason it can't be done), but wouldn't the simplest way to avoid the time out be to just implement a simple heartbeat animation - ie put a square in a corner and change its colour every 5 seconds?

[JohnStrunk]

@digilinCraig You're definitely thinking in the right direction.

On the older Chromecasts, as long as you publish a new image before the timeout, the timeout will reset and all will be good. The code that makes that happen is:

wahoo-results/imagecast.py

Lines 260 to 270 in feddf96

	# The refresh thread periodically re-publishes the current image to ensure
	# the Chromecast devices don't timeout.
	def _start_refresh(self) -> None:
	def _refresh_run():
	while True:
	time.sleep(_REFRESH_INTERVAL)
	if self.image is not None:
	self.publish(self.image)
	self._refresh_thread = threading.Thread(target=_refresh_run, daemon=True)
	self._refresh_thread.start()

And the refresh interval is defined at the top:

wahoo-results/imagecast.py

Lines 40 to 42 in feddf96

	# Chromecast image refresh interval (seconds)
	# Newer versions of the Chromecast firmware seem to have a 10 minute timeout
	_REFRESH_INTERVAL = 7 * 60

Unfortunately, the GoogleTV variants don't seem to reset their timeout when you display a new image. This probably wouldn't be an issue if the scoreboard were actually a video stream instead of static PNGs. However, I've resisted using a video stream because I'm concerned about load on the scoreboard computer plus having a good network connection between it and the Chromecast.

So the best I've got is the current "stay awake" workaround.