diff --git a/source/Lib/EncoderLib/EncNNFilter.h b/source/Lib/EncoderLib/EncNNFilter.h
index 1c17bbefcef27d5cb9b4fa2029f618ae2c9ca6fb..13aa502d640f680643c4cd2d27dc54296bfc3561 100644
--- a/source/Lib/EncoderLib/EncNNFilter.h
+++ b/source/Lib/EncoderLib/EncNNFilter.h
@@ -50,6 +50,12 @@
 #include <fstream>
 using namespace std;
 
+namespace sadl {
+template<typename T> class Model;
+template<typename T> class Tensor;
+}
+
+
 class EncNNFilter
 {
 public: