obs-webrtc: Add Simulcast Support

frontend/utility/BasicOutputHandler.hpp

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <utility/MultitrackVideoOutput.hpp>
+#include <utility/WHIPSimulcastEncoders.hpp>
 
 #include <obs.hpp>
 #include <util/dstr.hpp>
@@ -42,6 +43,8 @@ struct BasicOutputHandler {
 	obs_scene_t *vCamSourceScene = nullptr;
 	obs_sceneitem_t *vCamSourceSceneItem = nullptr;
 
+	std::unique_ptr<WHIPSimulcastEncoders> whipSimulcastEncoders;
+
 	std::string outputType;
 	std::string lastError;