diff --git a/CMakeTests/CheckLib.cmake b/CMakeTests/CheckLib.cmake
index c1174ecb58..affc92ae8f 100644
--- a/CMakeTests/CheckLib.cmake
+++ b/CMakeTests/CheckLib.cmake
@@ -63,6 +63,7 @@ macro(check_libav)
 	if(LIBAV_FOUND)
 		message("libav found, enabling AVI frame dumps")
 		add_definitions(-DHAVE_LIBAV)
+		include_directories(${LIBAV_INCLUDE_DIRS})
 	else()
 		message("libav not found, disabling AVI frame dumps")
 	endif()