Currently, the only playback devices that could be listed in the output switcher included the current device and any paired Bluetooth devices. But with the Google Cast SDK update and the new Android 13 ‘Stream Expansion’ feature, you will be able to expand the audio to multiple cast devices.
Originally, the feature was discovered back in Android 11, but it never made it to release. And now, it looks like Google will bring it to life with the Android 13 remote playback system API.
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But besides that, there has to support from the app side, so if you’re an app developer, I highly recommend checking out Mishaal Rahman’s article on Esper:
