diff --git a/libavcodec/h263dec.c b/libavcodec/h263dec.c
index 87c9e4991b..ac22bca8ef 100644
--- a/libavcodec/h263dec.c
+++ b/libavcodec/h263dec.c
@@ -514,7 +514,8 @@ retry:
 
     if(s->xvid_build==0 && s->divx_version==0 && s->lavc_build==0){
         if(s->avctx->stream_codec_tag == ff_get_fourcc("XVID") ||
-           s->avctx->codec_tag == ff_get_fourcc("XVID") || s->avctx->codec_tag == ff_get_fourcc("XVIX"))
+           s->avctx->codec_tag == ff_get_fourcc("XVID") || s->avctx->codec_tag == ff_get_fourcc("XVIX") ||
+           s->avctx->codec_tag == ff_get_fourcc("RMP4"))
             s->xvid_build= -1;
 #if 0
         if(s->avctx->codec_tag == ff_get_fourcc("DIVX") && s->vo_type==0 && s->vol_control_parameters==1
diff --git a/libavformat/avienc.c b/libavformat/avienc.c
index 8718b8ff94..3900799ad0 100644
--- a/libavformat/avienc.c
+++ b/libavformat/avienc.c
@@ -108,6 +108,8 @@ const CodecTag codec_bmp_tags[] = {
     { CODEC_ID_MPEG4, MKTAG('W', 'V', '1', 'F') },
     { CODEC_ID_MPEG4, MKTAG('S', 'E', 'D', 'G') },
 
+    { CODEC_ID_MPEG4, MKTAG('R', 'M', 'P', '4') },
+
     { CODEC_ID_MSMPEG4V3, MKTAG('D', 'I', 'V', '3'), .invalid_asf = 1 }, /* default signature when using MSMPEG4 */
     { CODEC_ID_MSMPEG4V3, MKTAG('M', 'P', '4', '3') },