diff --git a/.gitmodules b/.gitmodules
index f2e0d283..8ebdff3d 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,9 +1,15 @@
 [submodule "opencv"]
 	path = opencv
 	url = https://github.com/opencv/opencv.git
+        branch = 3.4
 [submodule "opencv_contrib"]
 	path = opencv_contrib
 	url = https://github.com/opencv/opencv_contrib.git
+        branch = 3.4
 [submodule "multibuild"]
 	path = multibuild
 	url = https://github.com/matthew-brett/multibuild.git
+[submodule "opencv_extra"]
+	path = opencv_extra
+	url = https://github.com/opencv/opencv_extra.git
+        branch = 3.4
diff --git a/opencv_extra b/opencv_extra
new file mode 160000
index 00000000..b6430dee
--- /dev/null
+++ b/opencv_extra
@@ -0,0 +1 @@
+Subproject commit b6430deee16b91dce946a6e66feb8dc110c39834