.

youtube_dl/extractor/youtube.py

@@ -2,7 +2,7 @@
 
 from __future__ import unicode_literals
 
-
+import requests
 import itertools
 import json
 import os.path
@@ -1780,6 +1780,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
                 # manifest pointed by get_video_info's dashmpd).
                 # The general idea is to take a union of itags of both DASH manifests (for example
                 # video with such 'manifest behavior' see https://github.com/ytdl-org/youtube-dl/issues/6093)
+                if self._downloader.params.get('youtube_extend_dash_manifest', False):
                     self.report_video_info_webpage_download(video_id)
                     for el in ('embedded', 'detailpage', 'vevo', ''):
                         query = {
@@ -1824,6 +1825,8 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
                             if not token:
                                 video_info = get_video_info
                             break
+                else:
+                    video_info = {'title': 'Unknown'}
 
         def extract_unavailable_message():
             messages = []