dvr-ms video decoding support

Originally committed as revision 3631 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/asf.c

@@ -295,6 +295,8 @@ static int asf_read_header(AVFormatContext *s, AVFormatParameters *ap)
 
                 st->codec.codec_tag = tag1;
 		st->codec.codec_id = codec_get_id(codec_bmp_tags, tag1);
+                if(tag1 == MKTAG('D', 'V', 'R', ' '))
+                    st->need_parsing = 1;
             }
             pos2 = url_ftell(pb);
             url_fskip(pb, gsize - (pos2 - pos1 + 24));

libavformat/avienc.c

@@ -134,6 +134,7 @@ const CodecTag codec_bmp_tags[] = {
     { CODEC_ID_MPEG1VIDEO, MKTAG('V', 'C', 'R', '2') }, 
     { CODEC_ID_MPEG1VIDEO, 0x10000001 }, 
     { CODEC_ID_MPEG2VIDEO, 0x10000002 }, 
+    { CODEC_ID_MPEG2VIDEO, MKTAG('D', 'V', 'R', ' ') },
     { CODEC_ID_MJPEG, MKTAG('M', 'J', 'P', 'G') },
     { CODEC_ID_MJPEG, MKTAG('L', 'J', 'P', 'G') },
     { CODEC_ID_LJPEG, MKTAG('L', 'J', 'P', 'G') },