diff --git a/src/mod/applications/mod_av/Makefile.am b/src/mod/applications/mod_av/Makefile.am
index e697d9ec93..ebf4c93929 100644
--- a/src/mod/applications/mod_av/Makefile.am
+++ b/src/mod/applications/mod_av/Makefile.am
@@ -36,5 +36,5 @@ else
 install: error
 all: error
 error:
-	$(error You must install libavformat-dev to build mod_av)
+	$(error You must install libavformat-dev and libswscale-dev to build mod_av)
 endif