matroska: add support for A_QUICKTIME/QDM2 codec

Originally committed as revision 14430 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/matroska.c

@@ -59,6 +59,7 @@ const CodecTags ff_mkv_codec_tags[]={
     {"A_REAL/ATRC"      , CODEC_ID_ATRAC3},
     {"A_REAL/COOK"      , CODEC_ID_COOK},
 //    {"A_REAL/SIPR"      , CODEC_ID_SIPRO},
+    {"A_QUICKTIME/QDM2" , CODEC_ID_QDM2},
 
     {"S_TEXT/UTF8"      , CODEC_ID_TEXT},
     {"S_TEXT/ASCII"     , CODEC_ID_TEXT},

libavformat/matroska.h

@@ -210,7 +210,7 @@ typedef enum {
  */
 
 typedef struct CodecTags{
-    char str[16];
+    char str[20];
     enum CodecID id;
 }CodecTags;