diff --git a/youtube_dl/extractor/discovery.py b/youtube_dl/extractor/discovery.py
index 7c554ec140..55853f76f9 100644
--- a/youtube_dl/extractor/discovery.py
+++ b/youtube_dl/extractor/discovery.py
@@ -71,7 +71,7 @@ def _real_extract(self, url):
         entries = []
 
         for idx, video_info in enumerate(info['playlist']):
-            subtitles = []
+            subtitles = {}
             caption_url = video_info.get('captionsUrl')
             if caption_url:
                 subtitles = {