diff --git a/docs/using_cmake_build.txt b/docs/using_cmake_build.txt
index 1e41b1d9..67077d27 100644
--- a/docs/using_cmake_build.txt
+++ b/docs/using_cmake_build.txt
@@ -19,3 +19,10 @@ Step 4) Compile the code.
 	~> make install
 
 Step 5) Use CCextractor as you would like
+
+
+If you want to build CCExtractor with FFMpeg you need to pass
+cmake -DWITH_FFMPEG=ON ../src/
+
+Hint for looking all the things you want to set from outside
+cmake -LAH ../src/