diff --git a/samplebuffer.cpp b/samplebuffer.cpp
index 6965ff7..95e6592 100644
--- a/samplebuffer.cpp
+++ b/samplebuffer.cpp
@@ -17,6 +17,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <QMutexLocker>
 #include "samplebuffer.h"
 
 template <typename Tin, typename Tout>
@@ -39,6 +40,7 @@ std::unique_ptr<Tout[]> SampleBuffer<Tin, Tout>::getSamples(off_t start, off_t l
     	return nullptr;
 
     std::unique_ptr<Tout[]> dest(new Tout[length]);
+    QMutexLocker ml(&mutex);
     work(samples.get(), dest.get(), length);
     return dest;
 }
diff --git a/samplebuffer.h b/samplebuffer.h
index cfbac64..8fd439e 100644
--- a/samplebuffer.h
+++ b/samplebuffer.h
@@ -19,6 +19,7 @@
 
 #pragma once
 
+#include <QMutex>
 #include <complex>
 #include <memory>
 #include "samplesource.h"
@@ -28,6 +29,7 @@ class SampleBuffer : public SampleSource<Tout>, public Subscriber
 {
 private:
     SampleSource<Tin> *src;
+    QMutex mutex;
 
 public:
     SampleBuffer(SampleSource<Tin> *src);