diff --git a/libavformat/yuv4mpeg.c b/libavformat/yuv4mpeg.c
index 54fbff57f8..1520b34635 100644
--- a/libavformat/yuv4mpeg.c
+++ b/libavformat/yuv4mpeg.c
@@ -53,7 +53,7 @@ static int yuv4_generate_header(AVFormatContext *s, char* buf)
                  raten, rated,
                  inter,
                  aspectn, aspectd,
-		 (st->codec.pix_fmt == PIX_FMT_YUV411P) ? " XYSCSS=411" : "");
+		 (st->codec.pix_fmt == PIX_FMT_YUV411P) ? " C411 XYSCSS=411" : " C420mpeg2 XYSCSS=420MPEG2");
 		 
     return n;
 }
diff --git a/tests/libav.regression.ref b/tests/libav.regression.ref
index 0cf3cbd95b..ada9b85d60 100644
--- a/tests/libav.regression.ref
+++ b/tests/libav.regression.ref
@@ -36,8 +36,8 @@ fb191b2d08006f875c59940ec25abf10 *./data/b-libav.nut
 ./data/b-libav.ppm CRC=b2bb8e92
 1cac531652ea2ff2fb141d5ae992caa8 *./data/b-libav.gif
 2907057 ./data/b-libav.gif
-995ab62524fd85ea1c017b69ead611c2 *./data/b-libav.yuv4mpeg
-3801784 ./data/b-libav.yuv4mpeg
+c39dd19b88f9e0f03a318b51c37edb61 *./data/b-libav.yuv4mpeg
+3801810 ./data/b-libav.yuv4mpeg
 ./data/b-libav%d.pgm CRC=84c09106
 ./data/b-libav%d.ppm CRC=25c06ecf
 4b7690747c49e4e8e910359768e4a77e *./data/b-libav.wav