diff --git a/include/libcamera/internal/software_isp/software_isp.h b/include/libcamera/internal/software_isp/software_isp.h
index 440a296d..af0dcc24 100644
--- a/include/libcamera/internal/software_isp/software_isp.h
+++ b/include/libcamera/internal/software_isp/software_isp.h
@@ -100,6 +100,7 @@ private:
 	DmaBufAllocator dmaHeap_;
 
 	std::unique_ptr<ipa::soft::IPAProxySoft> ipa_;
+	bool running_;
 };
 
 } /* namespace libcamera */
diff --git a/src/libcamera/software_isp/software_isp.cpp b/src/libcamera/software_isp/software_isp.cpp
index 44baf200..1a39f4d8 100644
--- a/src/libcamera/software_isp/software_isp.cpp
+++ b/src/libcamera/software_isp/software_isp.cpp
@@ -315,6 +315,7 @@ int SoftwareIsp::start()
 	int ret = ipa_->start();
 	if (ret)
 		return ret;
+	running_ = true;
 
 	ispWorkerThread_.start();
 	return 0;
@@ -328,6 +329,7 @@ void SoftwareIsp::stop()
 	ispWorkerThread_.exit();
 	ispWorkerThread_.wait();
 
+	running_ = false;
 	ipa_->stop();
 }
 
@@ -356,7 +358,8 @@ void SoftwareIsp::setSensorCtrls(const ControlList &sensorControls)
 
 void SoftwareIsp::statsReady(uint32_t frame, uint32_t bufferId)
 {
-	ispStatsReady.emit(frame, bufferId);
+	if (running_)
+		ispStatsReady.emit(frame, bufferId);
 }
 
 void SoftwareIsp::inputReady(FrameBuffer *input)