(Partly) support Metasoft MJPEG Codec, fixes half of issue 1611.

Originally committed as revision 20796 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mjpegdec.c

@@ -1182,7 +1182,8 @@ static int mjpeg_decode_com(MJpegDecodeContext *s)
             else if(!strcmp(cbuf, "CS=ITU601")){
                 s->cs_itu601= 1;
             }
-            else if(len > 20 && !strncmp(cbuf, "Intel(R) JPEG Library", 21)){
+            else if((len > 20 && !strncmp(cbuf, "Intel(R) JPEG Library", 21)) ||
+                    (len > 19 && !strncmp(cbuf, "Metasoft MJPEG Codec", 20))){
                 s->flipped = 1;
             }
 

libavformat/riff.c

@@ -138,6 +138,7 @@ const AVCodecTag ff_codec_bmp_tags[] = {
     { CODEC_ID_MJPEG,        MKTAG('M', 'V', 'J', 'P') }, /* Midvid JPEG Video Codec */
     { CODEC_ID_MJPEG,        MKTAG('A', 'V', 'I', '1') },
     { CODEC_ID_MJPEG,        MKTAG('A', 'V', 'I', '2') },
+    { CODEC_ID_MJPEG,        MKTAG('M', 'T', 'S', 'J') },
     { CODEC_ID_HUFFYUV,      MKTAG('H', 'F', 'Y', 'U') },
     { CODEC_ID_FFVHUFF,      MKTAG('F', 'F', 'V', 'H') },
     { CODEC_ID_CYUV,         MKTAG('C', 'Y', 'U', 'V') },