diff --git a/include/libcamera/ipa/mali-c55.mojom b/include/libcamera/ipa/mali-c55.mojom
index 5d7eb4ee..39b7f1f1 100644
--- a/include/libcamera/ipa/mali-c55.mojom
+++ b/include/libcamera/ipa/mali-c55.mojom
@@ -28,7 +28,7 @@ interface IPAMaliC55Interface {
 };
 
 interface IPAMaliC55EventInterface {
-	paramsComputed(uint32 request);
+	paramsComputed(uint32 request, uint32 bytesused);
 	statsProcessed(uint32 request, libcamera.ControlList metadata);
 	setSensorControls(libcamera.ControlList sensorControls);
 };
diff --git a/src/ipa/mali-c55/mali-c55.cpp b/src/ipa/mali-c55/mali-c55.cpp
index c6941a95..5877f299 100644
--- a/src/ipa/mali-c55/mali-c55.cpp
+++ b/src/ipa/mali-c55/mali-c55.cpp
@@ -346,7 +346,8 @@ void IPAMaliC55::fillParams(unsigned int request,
 		ASSERT(params->total_size <= MALI_C55_PARAMS_MAX_SIZE);
 	}
 
-	paramsComputed.emit(request);
+	size_t bytesused = offsetof(struct mali_c55_params_buffer, data) + params->total_size;
+	paramsComputed.emit(request, bytesused);
 }
 
 void IPAMaliC55::processStats(unsigned int request, unsigned int bufferId,
diff --git a/src/libcamera/pipeline/mali-c55/mali-c55.cpp b/src/libcamera/pipeline/mali-c55/mali-c55.cpp
index 4acc091b..17ad2055 100644
--- a/src/libcamera/pipeline/mali-c55/mali-c55.cpp
+++ b/src/libcamera/pipeline/mali-c55/mali-c55.cpp
@@ -618,7 +618,7 @@ public:
 	void imageBufferReady(FrameBuffer *buffer);
 	void paramsBufferReady(FrameBuffer *buffer);
 	void statsBufferReady(FrameBuffer *buffer);
-	void paramsComputed(unsigned int requestId);
+	void paramsComputed(unsigned int requestId, uint32_t bytesused);
 	void statsProcessed(unsigned int requestId, const ControlList &metadata);
 
 	bool match(DeviceEnumerator *enumerator) override;
@@ -1494,7 +1494,7 @@ void PipelineHandlerMaliC55::statsBufferReady(FrameBuffer *buffer)
 				 sensorControls);
 }
 
-void PipelineHandlerMaliC55::paramsComputed(unsigned int requestId)
+void PipelineHandlerMaliC55::paramsComputed(unsigned int requestId, uint32_t bytesused)
 {
 	MaliC55FrameInfo &frameInfo = frameInfoMap_[requestId];
 	Request *request = frameInfo.request;
@@ -1505,8 +1505,7 @@ void PipelineHandlerMaliC55::paramsComputed(unsigned int requestId)
 	 * video devices.
 	 */
 
-	frameInfo.paramBuffer->_d()->metadata().planes()[0].bytesused =
-		sizeof(struct mali_c55_params_buffer);
+	frameInfo.paramBuffer->_d()->metadata().planes()[0].bytesused = bytesused;
 	params_->queueBuffer(frameInfo.paramBuffer);
 	stats_->queueBuffer(frameInfo.statBuffer);