diff --git a/youtube_dl/extractor/common.py b/youtube_dl/extractor/common.py
index f9e8e2bad1..e5245ec3f2 100644
--- a/youtube_dl/extractor/common.py
+++ b/youtube_dl/extractor/common.py
@@ -1062,6 +1062,9 @@ class InfoExtractor(object):
     def _get_automatic_captions(self, *args, **kwargs):
         raise NotImplementedError("This method must be implemented by subclasses")
 
+    def _subtitles_timecode(self, seconds):
+        return '%02d:%02d:%02d.%03d' % (seconds / 3600, (seconds % 3600) / 60, seconds % 60, (seconds % 1) * 1000)
+
 
 class SearchInfoExtractor(InfoExtractor):
     """