diff --git a/youtube_dl/extractor/youtube.py b/youtube_dl/extractor/youtube.py
index a7f8c968e..1fef4cfd4 100644
--- a/youtube_dl/extractor/youtube.py
+++ b/youtube_dl/extractor/youtube.py
@@ -918,7 +918,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
             if lang in sub_lang_list:
                 continue
             sub_formats = []
-            for ext in ['sbv', 'vtt', 'srt']:
+            for ext in ['vtt', 'ttml']:
                 params = compat_urllib_parse.urlencode({
                     'lang': lang,
                     'v': video_id,