The integration will select the first media player in the mapping as the sink and it will be the entity that services like volume controls are sent to.
It will follow the selected source of the sink, down to the root selected source media player entity, which will be considered the media source. It will be the target of services like play/pause/stop. For example media_player.tv[HDMI 2] -> media_player.stereo[PVR] - > media_player.bedroom
This example configuration will use the demo sources as root sources.
media_player:
- platform: demo
- platform: media_stack
name: My Stack
mapping:
media_player.tv:
"HDMI 1": media_player.lounge_room
"HDMI 2": media_player.stereo
media_player.stereo:
PVR: media_player.bedroom
DISPLAY: media_player.philips_tv
AUX: media_player.walkman
AV: media_player.living_room