Question: How does group volume controle work

[svrooij]

I'm also struggling with this issue. I figured out how to start for example Radio 3FM on my speakers. I do this by sending this message to the coördinator speaker 'wittekast keuken' (sonos/wittekast-keuken/control):
{ "command": "setavtransporturi",
"input": "radio:s6707?sid=254&flags=32"}

This works fine, both the speaker 'wittekast keuken' and 'keuken' (which are in the same group), play 3FM. However, when I want to increase the volume of both speakers it does not work. I send the following message also to the coördinator speaker 'wittekast keuken' (sonos/wittekast-keuken/control):
{ "command": "volumeup",
"input": 5}

Now only the volume of the 'wittekast keuken' is raised by 5. The volume of the member 'keuken' remains unchanged. Do I miss something somewhere?

Originally posted by @viimD in #110 (comment)

[svrooij]

Volume is per speaker, but some commands are automatically redirected to the group coordinator.

You can however send a special group command (to the coordinator of that group, else it will return an error).

Send an advanced command to the GroupRenderingControlService.

Topic: sonos/wittekast-keuken/control
Payload:

{
  "command": "adv-command",
  "input": {
    "cmd": "GroupRenderingControlService.SetRelativeGroupVolume",
    "val": {
      "InstanceID": 0,
      "Adjustment": 20
    }
  }
}

This will execute the SetRelativeGroupVolume command. The InstanceID always has to be 0 and the Adjustment can be any number between -100 and +100. This will be the relative adjustment. If the speakers where not at the same volume, the adjustment is also computed for all speakers separate.

[viimD]

Thanks Stephan! The use of advanced commands works like a charm!