[jsonapi] apply rating meta update to media if supported through ffmp…

…eg AVDictionary api

src/httpd_jsonapi.c

@@ -3686,6 +3686,26 @@ track_sync_rating(const struct db_media_file_info *dbmfi, unsigned *updated, uns
     char rating[5] = { '\0' };
     char dest[PATH_MAX];
 
+    // keep in sync with scan_metadata_ffmpeg and incl types supported by ffmpeg AVDictionary interface
+    static const char *supported_meta[] = {
+      "mpeg", "flac", NULL
+    };
+    const char **supported = supported_meta;
+    while (*supported)
+      {
+	if (strcmp(dbmfi->codectype, *supported) == 0) {
+	    break;
+	}
+	++supported;
+      }
+    if (*supported == NULL)
+      {
+	// unsupported rating, dont bother
+	// using stream[x]->codecpar but this is already known in db and via dbmfi
+	DPRINTF(E_WARN, L_WEB, "unsupported metadata update for 'rating' on '%s' (%s) - skipping\n", dbmfi->path, dbmfi->codectype);
+	return ENOEXEC;
+      }
+
     AVFormatContext*  ctx = NULL;
     if ( (ret = avformat_open_input(&ctx, dbmfi->path, NULL, NULL)) != 0)
       {