diff --git a/UI/window-projector.cpp b/UI/window-projector.cpp
index 565c57e80e787353e2c757aa9de22800ea35eb5e..cffa8f193099452026529f29ec7ab74effad1c2a 100644
--- a/UI/window-projector.cpp
+++ b/UI/window-projector.cpp
@@ -329,7 +329,7 @@ void OBSProjector::OBSRenderMultiview(void *data, uint32_t cx, uint32_t cy)
 		gs_projection_pop();
 	};
 
-	auto calcBaseSource = [&](int i)
+	auto calcBaseSource = [&](size_t i)
 	{
 		switch (multiviewLayout) {
 		case VERTICAL_LEFT: