Unable to get stream uri because of soap validation constraint violation

[tozman51]

On a PTZ camera, I can get Presets, send presets etc, but I didn't manage to get the stream URI unfortunately, despite spending hours tinkering with the library and checking the ONVIF specs...

Here is how I ask for streams :

$o = new Rockyjvec\Onvif\Onvif("http://192.168.1.47:81/onvif/device_service", "admin", "password");
$o->media->GetProfiles();

$params = [
			'StreamSetup'=>
				[	
					'Stream'=>'RTP-Unicast',
					'Transport'=>
						[
							'Protocol'=>'RTSP'
						]
				],
				'ProfileToken' => 'profile_cam1_stream1'
		  ];
		  
print_r($o->media->GetStreamUri($params));

And here is the output :

PHP Fatal error: Uncaught SoapFault exception: [s:Client] Validation constraint violation: empty value provided where a value is required in element 'SOAP-ENC:Struct' in /home/nicolas/Projets/onphp/vendor/rockyjvec/onvif/src/Rockyjvec/Onvif/Soap/SoapClient.php:75

If someone passes by and succesfully cot their camera stream uri :) any help is welcome.