diff --git a/src/ipa/raspberrypi/controller/denoise_algorithm.hpp b/src/ipa/raspberrypi/controller/denoise_algorithm.hpp
new file mode 100644
index 000000000000..df1f35cc9e5f
--- /dev/null
+++ b/src/ipa/raspberrypi/controller/denoise_algorithm.hpp
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: BSD-2-Clause */
+/*
+ * Copyright (C) 2021, Raspberry Pi (Trading) Limited
+ *
+ * denoise.hpp - Denoise control algorithm interface
+ */
+#pragma once
+
+#include "algorithm.hpp"
+
+namespace RPiController {
+
+enum DenoiseMode { Off, ColourOff, ColourFast, ColourHighQuality };
+
+class DenoiseAlgorithm : public Algorithm
+{
+public:
+	DenoiseAlgorithm(Controller *controller) : Algorithm(controller) {}
+	// A Denoise algorithm must provide the following:
+	virtual void SetMode(DenoiseMode mode) = 0;
+};
+
+} // namespace RPiController
diff --git a/src/ipa/raspberrypi/controller/denoise_status.h b/src/ipa/raspberrypi/controller/denoise_status.h
index 06d7cfb91ae8..6064cc2c192e 100644
--- a/src/ipa/raspberrypi/controller/denoise_status.h
+++ b/src/ipa/raspberrypi/controller/denoise_status.h
@@ -16,6 +16,7 @@ struct DenoiseStatus {
 	double noise_constant;
 	double noise_slope;
 	double strength;
+	unsigned int mode;
 };
 
 #ifdef __cplusplus
diff --git a/src/ipa/raspberrypi/controller/rpi/sdn.cpp b/src/ipa/raspberrypi/controller/rpi/sdn.cpp
index d8c1521a6633..ecc7845eda4c 100644
--- a/src/ipa/raspberrypi/controller/rpi/sdn.cpp
+++ b/src/ipa/raspberrypi/controller/rpi/sdn.cpp
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: BSD-2-Clause */
 /*
- * Copyright (C) 2019, Raspberry Pi (Trading) Limited
+ * Copyright (C) 2019-2021, Raspberry Pi (Trading) Limited
  *
  * sdn.cpp - SDN (spatial denoise) control algorithm
  */
@@ -18,7 +18,7 @@ using namespace RPiController;
 #define NAME "rpi.sdn"
 
 Sdn::Sdn(Controller *controller)
-	: Algorithm(controller)
+	: DenoiseAlgorithm(controller), mode_(DenoiseMode::ColourOff)
 {
 }
 
@@ -48,6 +48,7 @@ void Sdn::Prepare(Metadata *image_metadata)
 	status.noise_constant = noise_status.noise_constant * deviation_;
 	status.noise_slope = noise_status.noise_slope * deviation_;
 	status.strength = strength_;
+	status.mode = mode_;
 	image_metadata->Set("denoise.status", status);
 	RPI_LOG("Sdn: programmed constant " << status.noise_constant
 					    << " slope " << status.noise_slope
@@ -55,6 +56,12 @@ void Sdn::Prepare(Metadata *image_metadata)
 					    << status.strength);
 }
 
+void Sdn::SetMode(DenoiseMode mode)
+{
+	// We only distinguish between off and all other modes.
+	mode_ = mode;
+}
+
 // Register algorithm with the system.
 static Algorithm *Create(Controller *controller)
 {
diff --git a/src/ipa/raspberrypi/controller/rpi/sdn.hpp b/src/ipa/raspberrypi/controller/rpi/sdn.hpp
index 486c000d7b77..2371ce04163f 100644
--- a/src/ipa/raspberrypi/controller/rpi/sdn.hpp
+++ b/src/ipa/raspberrypi/controller/rpi/sdn.hpp
@@ -7,12 +7,13 @@
 #pragma once
 
 #include "../algorithm.hpp"
+#include "../denoise_algorithm.hpp"
 
 namespace RPiController {
 
 // Algorithm to calculate correct spatial denoise (SDN) settings.
 
-class Sdn : public Algorithm
+class Sdn : public DenoiseAlgorithm
 {
 public:
 	Sdn(Controller *controller = NULL);
@@ -20,10 +21,12 @@ public:
 	void Read(boost::property_tree::ptree const &params) override;
 	void Initialise() override;
 	void Prepare(Metadata *image_metadata) override;
+	void SetMode(DenoiseMode mode) override;
 
 private:
 	double deviation_;
 	double strength_;
+	DenoiseMode mode_;
 };
 
 } // namespace RPiController