lower case div3

Originally committed as revision 1218 to svn://svn.ffmpeg.org/ffmpeg/trunk

libav/avienc.c

@@ -71,6 +71,7 @@ const CodecTag codec_bmp_tags[] = {
     { CODEC_ID_MPEG4, MKTAG('m', '4', 's', '2') },
     { CODEC_ID_MPEG4, MKTAG(0x04, 0, 0, 0) }, /* some broken avi use this */
     { CODEC_ID_MSMPEG4V3, MKTAG('D', 'I', 'V', '3'), .invalid_asf = 1 }, /* default signature when using MSMPEG4 */
+    { CODEC_ID_MSMPEG4V3, MKTAG('d', 'i', 'v', '3'), .invalid_asf = 1 },
     { CODEC_ID_MSMPEG4V3, MKTAG('M', 'P', '4', '3') }, 
     { CODEC_ID_MSMPEG4V2, MKTAG('M', 'P', '4', '2') }, 
     { CODEC_ID_MSMPEG4V1, MKTAG('M', 'P', 'G', '4') },