diff --git a/common/rfb/ScaledPixelBuffer.cxx b/common/rfb/ScaledPixelBuffer.cxx
index 5892a97..e459b39 100644
--- a/common/rfb/ScaledPixelBuffer.cxx
+++ b/common/rfb/ScaledPixelBuffer.cxx
@@ -51,9 +51,7 @@
 }
 
 void ScaledPixelBuffer::setPF(const PixelFormat &pf_) {
-  if (pf_.depth != 24) {
-    throw rfb::Exception("rfb::ScaledPixelBuffer support only the true colour pixel format.");
-  }
+  if (pf_.depth != 24) throw rfb::UnsupportedPixelFormatException();
   pf = pf_;
 }
 
diff --git a/common/rfb/ScaledPixelBuffer.h b/common/rfb/ScaledPixelBuffer.h
index d69f0ac..8af6957 100644
--- a/common/rfb/ScaledPixelBuffer.h
+++ b/common/rfb/ScaledPixelBuffer.h
@@ -23,6 +23,7 @@
 // interpolation.
 
 #include <rdr/types.h>
+#include <rdr/Exception.h>
 #include <rfb/Rect.h>
 #include <rfb/PixelFormat.h>
 
@@ -30,6 +31,11 @@
 
 namespace rfb {
 
+  struct UnsupportedPixelFormatException : public Exception {
+    UnsupportedPixelFormatException(const char* s="Now supported only true colour pixel data in the scaling mode.")
+      : Exception(s) {}
+  };
+
   class ScaledPixelBuffer {
   public:
     ScaledPixelBuffer(U8 **data, int width, int height, int scale, PixelFormat pf);