diff --git a/libavformat/riff.c b/libavformat/riff.c
index cf5a2ffa5a01f4b9ab57ef12a4d2d5e915561907..2641a531ecab68b51c793ea3fd175e5e5205432a 100644
--- a/libavformat/riff.c
+++ b/libavformat/riff.c
@@ -113,6 +113,7 @@ const AVCodecTag ff_codec_bmp_tags[] = {
     { AV_CODEC_ID_MPEG4,        MKTAG('G', 'L', 'V', '4') },
     { AV_CODEC_ID_MPEG4,        MKTAG('G', 'M', 'P', '4') }, /* GeoVision camera */
     { AV_CODEC_ID_MPEG4,        MKTAG('M', 'N', 'M', '4') }, /* March Networks DVR */
+    { AV_CODEC_ID_MPEG4,        MKTAG('G', 'T', 'M', '4') }, /* Telefactor */
     { AV_CODEC_ID_MSMPEG4V3,    MKTAG('M', 'P', '4', '3') },
     { AV_CODEC_ID_MSMPEG4V3,    MKTAG('D', 'I', 'V', '3') },
     { AV_CODEC_ID_MSMPEG4V3,    MKTAG('M', 'P', 'G', '3') },