diff --git a/libavformat/mtv.c b/libavformat/mtv.c
index fff72b4739..7a68ea97f3 100644
--- a/libavformat/mtv.c
+++ b/libavformat/mtv.c
@@ -104,6 +104,7 @@ static int mtv_read_header(AVFormatContext *s, AVFormatParameters *ap)
     av_set_pts_info(st, 64, 1, mtv->video_fps);
     st->codec->codec_type      = CODEC_TYPE_VIDEO;
     st->codec->codec_id        = CODEC_ID_RAWVIDEO;
+    st->codec->codec_tag       = MKTAG('R', 'G', 'B', mtv->img_bpp);
     st->codec->width           = mtv->img_width;
     st->codec->height          = mtv->img_height;
     st->codec->bits_per_sample = mtv->img_bpp;