diff --git a/libavformat/riff.c b/libavformat/riff.c
index a279121369..fbd40d4727 100644
--- a/libavformat/riff.c
+++ b/libavformat/riff.c
@@ -112,6 +112,7 @@ const AVCodecTag codec_bmp_tags[] = {
     { CODEC_ID_MPEG1VIDEO,   MKTAG('V', 'C', 'R', '2') },
     { CODEC_ID_MPEG1VIDEO,   MKTAG( 1 ,  0 ,  0 ,  16) },
     { CODEC_ID_MPEG2VIDEO,   MKTAG( 2 ,  0 ,  0 ,  16) },
+    { CODEC_ID_MPEG4,        MKTAG( 4 ,  0 ,  0 ,  16) },
     { CODEC_ID_MPEG2VIDEO,   MKTAG('D', 'V', 'R', ' ') },
     { CODEC_ID_MPEG2VIDEO,   MKTAG('M', 'M', 'E', 'S') },
     { CODEC_ID_MPEG2VIDEO,   MKTAG('L', 'M', 'P', '2') }, /* Lead MPEG2 in avi */