[youtube] Skip get_video_info requests when --youtube-skip-dash-manifest is specified

youtube_dl/extractor/youtube.py

@@ -894,6 +894,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
                     # Convert to the same format returned by compat_parse_qs
                     video_info = dict((k, [v]) for k, v in args.items())
                     add_dash_mpd(video_info)
+            if not video_info or self._downloader.params.get('youtube_include_dash_manifest', True):
                 # We also try looking in get_video_info since it may contain different dashmpd
                 # URL that points to a DASH manifest with possibly different itag set (some itags
                 # are missing from DASH manifest pointed by webpage's dashmpd, some - from DASH