diff --git a/libavformat/matroska.c b/libavformat/matroska.c
index 9b0cc06dcf..382534e9bd 100644
--- a/libavformat/matroska.c
+++ b/libavformat/matroska.c
@@ -68,6 +68,6 @@ const CodecTags ff_mkv_codec_tags[]={
     {"S_SSA"            , CODEC_ID_SSA},
     {"S_VOBSUB"         , CODEC_ID_DVD_SUBTITLE},
 
-    {NULL               , CODEC_ID_NONE}
+    {""                 , CODEC_ID_NONE}
 /* TODO: AC3-9/10 (?), Real, Musepack, Quicktime */
 };
diff --git a/libavformat/matroska.h b/libavformat/matroska.h
index b8d39bbcee..43fbb9e9c5 100644
--- a/libavformat/matroska.h
+++ b/libavformat/matroska.h
@@ -181,7 +181,7 @@ typedef enum {
  */
 
 typedef struct CodecTags{
-    const char *str;
+    char str[16];
     enum CodecID id;
 }CodecTags;
 
diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index ccf636b597..cc45e9599c 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -2048,7 +2048,7 @@ matroska_read_header (AVFormatContext    *s,
             if (track->codec_id == NULL)
                 continue;
 
-            for(j=0; ff_mkv_codec_tags[j].str; j++){
+            for(j=0; ff_mkv_codec_tags[j].id != CODEC_ID_NONE; j++){
                 if(!strncmp(ff_mkv_codec_tags[j].str, track->codec_id,
                             strlen(ff_mkv_codec_tags[j].str))){
                     codec_id= ff_mkv_codec_tags[j].id;