I have seen numerous situations during which the "Cast my audio" features in the Google Home app fails to work from my Galaxy S22 Ultra or Galaxy Tab S7+. Normally, when it all works, the procedure is :
1. open Google Home app on mobile device
2. select the Chromecast audio device in the device list
3. select "Cast my audio"
4. when prompted to "Cast to mirror device", select "cast audio"
5. when prompted to "start recording or casting ?", select "start now" .
6. The startup sound is heard, since I have that feature enabled.
In many cases, I get stuck after step 4. The prompt to "start recording or casting ?" in step 5 does not appear.
I have not been able to create a fully reproducible test case that triggers this intermittent failure, unfortunately. I know the root cause is likely that my Chromecast audio devices are not running 24/7. I turn them on and off manually with smartplugs, along with the cheap but power-hungry audio receivers I use as amplifiers, which don't support audio auto-sensing. Also, I use HomeAssistant to power off everything (meaning CCAs & amps) automatically after 3 hours of usage, in case I forgot to manually turn them off.
At some point, the Google Home app loses sync with the Chromecast audio device it was last connected to, and the "Cast my audio" feature just stops working. When this happens, cast-enabled apps, for example, Apple Music, are still able to successfully cast to the Chromecast audio device. Only the Google Home app gets into the broken state.
To get "Cast my audio" to work again when this situation happens, the only fix I found is to reboot the mobile device. That takes a lot of time, requires entering the device password, and is an inconvenient workaround I would like to avoid.
I have seen a variety of other bugs related to the Google Home app showing improper state :
1) showing the app is connected to the CCA, when the device is actually powered off
2) showing "now playing" on top and the "stop casting" button at the bottom, when audio is not currently casting to the CCA, but rather, currently being heard through the phone's built-in speaker
3) the "cast my audio" feature works, ie. device audio is heard through the CCA. However, the Google Home app user interface shows "not playing" on top, and does not show the "stop casting" button at the bottom, but instead shows the "cast my audio" button. Pressing this "cast my audio" button in this situation does however stop the casting.
I saw all these issues in the last couple of hours trying to create a reproducible test case, by powering the CCA off/on manually at various times, while device audio casting was on or off.
I realize each device doesn't consume a lot of power, but when one has a lot of them as I do - dozens - it all adds up, and I'm choosing to not keep them powered on 24/7 in order to reduce load on the electric grid, and my bill.
I could keep the CCAs powered on and switch just the amps. However, I find that provides a poor user experience - all speakers show up all the time in cast-enabled apps 24/7, including the Google Home app, even when the associated amplifiers are powered off. So, I prefer to switch both the CCAs and the amps simultaneously - this way, I know if a device shows up in the app that the amplifier is on as well. This works fine for all cast-enabled apps, except for the Google Home app itself when trying to use "Cast my audio", because the app is confused about the device state. I'm guessing it must be caching the last device state somewhere internally, and simply fails to notice when the device has powered off and back on, ie. rebooted. This leads to the various bugs I am experiencing.
