diff --git a/src/s_sound.c b/src/s_sound.c
index e614f929..00f0eadd 100644
--- a/src/s_sound.c
+++ b/src/s_sound.c
@@ -718,16 +718,9 @@ void S_ChangeMusic(int musicnum, int looping)
 
     // load & register it
     music->data = W_CacheLumpNum(music->lumpnum, PU_STATIC);
-    if (extra_music && trakinfo_found)
+    if (extra_music)
     {
-        const char *extra =
-            S_GetExtra(music->data, W_LumpLength(music->lumpnum), extra_music);
-        if (extra)
-        {
-            music->lumpnum = W_GetNumForName(extra);
-            Z_Free(music->data);
-            music->data = W_CacheLumpNum(music->lumpnum, PU_STATIC);
-        }
+        S_GetExtra(music, extra_music);
     }
     // julian: added lump length
     music->handle = I_RegisterSong(music->data, W_LumpLength(music->lumpnum));
@@ -782,16 +775,9 @@ void S_ChangeMusInfoMusic(int lumpnum, int looping)
     music->lumpnum = lumpnum;
 
     music->data = W_CacheLumpNum(music->lumpnum, PU_STATIC);
-    if (extra_music && trakinfo_found)
+    if (extra_music)
     {
-        const char *extra =
-            S_GetExtra(music->data, W_LumpLength(music->lumpnum), extra_music);
-        if (extra)
-        {
-            music->lumpnum = W_GetNumForName(extra);
-            Z_Free(music->data);
-            music->data = W_CacheLumpNum(music->lumpnum, PU_STATIC);
-        }
+        S_GetExtra(music, extra_music);
     }
     music->handle = I_RegisterSong(music->data, W_LumpLength(music->lumpnum));
 
diff --git a/src/s_trakinfo.c b/src/s_trakinfo.c
index bb9c14b9..da79769c 100644
--- a/src/s_trakinfo.c
+++ b/src/s_trakinfo.c
@@ -21,6 +21,8 @@
 #include "m_json.h"
 #include "m_misc.h"
 #include "sha1.h"
+#include "sounds.h"
+#include "w_wad.h"
 
 boolean trakinfo_found;
 
@@ -70,15 +72,21 @@ void S_ParseTrakInfo(int lumpnum)
     trakinfo_found = true;
 }
 
-const char *S_GetExtra(byte *data, int length, extra_music_t type)
+void S_GetExtra(musicinfo_t *music, extra_music_t type)
 {
+    if (!trakinfo_found)
+    {
+        return;
+    }
+
     sha1_context_t sha1_context;
     sha1_digest_t digest;
 
     SHA1_Init(&sha1_context);
-    SHA1_Update(&sha1_context, data, length);
+    SHA1_Update(&sha1_context, music->data, W_LumpLength(music->lumpnum));
     SHA1_Final(digest, &sha1_context);
 
+    const char *extra = NULL;
     trakinfo_t *trak;
     array_foreach(trak, trakinfo)
     {
@@ -86,13 +94,28 @@ const char *S_GetExtra(byte *data, int length, extra_music_t type)
         {
             if (type == EXMUS_REMIX)
             {
-                return trak->remix;
+                extra = trak->remix;
             }
             else
             {
-                return trak->midi;
+                extra = trak->midi;
             }
+            break;
         }
     }
-    return NULL;
+    if (!extra)
+    {
+        I_Printf(VB_DEBUG, "TRAKINFO: extra track is not found");
+        return;
+    }
+
+    int lumpnum = W_GetNumForName(extra);
+    if (lumpnum < 0)
+    {
+        I_Printf(VB_ERROR, "TRAKINFO: lump '%s' is not found", extra);
+        return;
+    }
+    music->lumpnum = lumpnum;
+    Z_Free(music->data);
+    music->data = W_CacheLumpNum(music->lumpnum, PU_STATIC);
 }
diff --git a/src/s_trakinfo.h b/src/s_trakinfo.h
index 8557f2a1..fed73135 100644
--- a/src/s_trakinfo.h
+++ b/src/s_trakinfo.h
@@ -27,6 +27,8 @@ typedef enum
     EXMUS_ORIGINAL
 } extra_music_t;
 
-const char *S_GetExtra(byte *data, int length, extra_music_t type);
+struct musicinfo_s;
+
+void S_GetExtra(struct musicinfo_s *music, extra_music_t type);
 
 #endif
diff --git a/src/sounds.h b/src/sounds.h
index c3155d93..ca418d15 100644
--- a/src/sounds.h
+++ b/src/sounds.h
@@ -81,7 +81,8 @@ typedef struct sfxinfo_s
 // MusicInfo struct.
 //
 
-typedef struct {
+typedef struct musicinfo_s
+{
   // up to 6-character name
   char *name;