+enum ChangeType
+{
+ CHANGE_TYPE_PENDING,
+ CHANGE_TYPE_DONE,
+ CHANGE_TYPE_CANCELLED
+};
+
+/** Type of captions.
+ *
+ * The generally accepted definitions seem to be:
+ * - subtitles: text for an audience who doesn't speak the film's language
+ * - captions: text for a hearing-impaired audience
+ * - open: on-screen
+ * - closed: only visible by some audience members
+ *
+ * At the moment DoM supports open subtitles and closed captions.
+ *
+ * There is some use of the word `subtitle' in the code which may mean
+ * caption in some contexts.
+ */