diff --git a/libavformat/os_support.h b/libavformat/os_support.h
index b419efa408..f2ff38e23b 100644
--- a/libavformat/os_support.h
+++ b/libavformat/os_support.h
@@ -42,6 +42,7 @@
 
 #ifdef _WIN32
 #  include <fcntl.h>
+#  include <stdint.h>
 #  ifdef lseek
 #   undef lseek
 #  endif