diff --git a/multimedia/openh264/Makefile b/multimedia/openh264/Makefile
index e8ee68f3be8c..1b7ddcf6f17f 100644
--- a/multimedia/openh264/Makefile
+++ b/multimedia/openh264/Makefile
@@ -43,7 +43,8 @@ PLUGINS_USES=	webplugin:gecko
 WEBPLUGIN_NAME=	gmp-gmp${PORTNAME}
 WEBPLUGIN_FILES=gmp${PORTNAME}.info libgmp${PORTNAME}.so
 SUB_FILES+=	gmp${PORTNAME}.js
-SUB_LIST+=	PORTVERSION=${PORTVERSION} TIMESTAMP="`date +%s`"
+SUB_LIST+=	PORTVERSION=${PORTVERSION} \
+		TIMESTAMP="`${AWK} '/TIMESTAMP/ { print $$$$$$$$$3 }' ${DISTINFO_FILE}`"
 
 TEST_BUILD_DEPENDS=googletest>=1.6.0:devel/googletest
 TEST_CFLAGS=	-I${LOCALBASE}/include