diff --git a/src/db.h b/src/db.h
index bf08c3ce..dc2a77b3 100644
--- a/src/db.h
+++ b/src/db.h
@@ -95,12 +95,13 @@ enum media_kind {
 };
 
 enum data_kind {
-  DATA_KIND_FILE = 0,
-  DATA_KIND_URL = 1,
-  DATA_KIND_SPOTIFY = 2,
-  DATA_KIND_PIPE = 3,
+  DATA_KIND_FILE = 0,    /* normal file */
+  DATA_KIND_URL = 1,     /* url/stream */
+  DATA_KIND_SPOTIFY = 2, /* iTunes has no spotify data kind, but we use 2 */
+  DATA_KIND_PIPE = 3,    /* iTunes has no pipe data kind, but we use 3 */
 };
 
+/* Note that fields marked as integers in the metadata map in filescanner_ffmpeg must be uint32_t here */
 struct media_file_info {
   char *path;
   uint32_t index;
diff --git a/src/filescanner.c b/src/filescanner.c
index 2c3ea855..ab6f7200 100644
--- a/src/filescanner.c
+++ b/src/filescanner.c
@@ -691,12 +691,12 @@ filescanner_process_media(char *path, time_t mtime, off_t size, int type, struct
 
   if (type & F_SCAN_TYPE_FILE)
     {
-      mfi->data_kind = DATA_KIND_FILE; /* real file */
+      mfi->data_kind = DATA_KIND_FILE;
       ret = scan_metadata_ffmpeg(path, mfi);
     }
   else if (type & F_SCAN_TYPE_URL)
     {
-      mfi->data_kind = DATA_KIND_URL; /* url/stream */
+      mfi->data_kind = DATA_KIND_URL;
       ret = scan_metadata_ffmpeg(path, mfi);
       if (ret < 0)
 	{
@@ -709,12 +709,12 @@ filescanner_process_media(char *path, time_t mtime, off_t size, int type, struct
     }
   else if (type & F_SCAN_TYPE_SPOTIFY)
     {
-      mfi->data_kind = DATA_KIND_SPOTIFY; /* iTunes has no spotify data kind, but we use 2 */
+      mfi->data_kind = DATA_KIND_SPOTIFY;
       ret = mfi->artist && mfi->album && mfi->title;
     }
   else if (type & F_SCAN_TYPE_PIPE)
     {
-      mfi->data_kind = DATA_KIND_PIPE; /* iTunes has no pipe data kind, but we use 3 */
+      mfi->data_kind = DATA_KIND_PIPE;
       mfi->type = strdup("wav");
       mfi->codectype = strdup("wav");
       mfi->description = strdup("PCM16 pipe");