[youtube:tab] Improve identity token extraction (closes #27197)

youtube_dl/extractor/youtube.py

@@ -3121,6 +3121,19 @@ class YoutubeTabIE(YoutubeBaseInfoExtractor):
             self._playlist_entries(playlist), playlist_id=playlist_id,
             playlist_title=title)
 
+    def _extract_identity_token(self, webpage, item_id):
+        ytcfg = self._parse_json(
+            self._search_regex(
+                r'ytcfg\.set\s*\(\s*({.+?})\s*\)\s*;', webpage, 'ytcfg',
+                default='{}'), item_id, fatal=False)
+        if ytcfg:
+            token = try_get(ytcfg, lambda x: x['ID_TOKEN'], compat_str)
+            if token:
+                return token
+        return self._search_regex(
+            r'\bID_TOKEN["\']\s*:\s*["\'](.+?)["\']', webpage,
+            'identity token', default=None)
+
     def _real_extract(self, url):
         item_id = self._match_id(url)
         url = compat_urlparse.urlunparse(
@@ -3135,9 +3148,7 @@ class YoutubeTabIE(YoutubeBaseInfoExtractor):
                 return self.url_result(video_id, ie=YoutubeIE.ie_key(), video_id=video_id)
             self.to_screen('Downloading playlist %s - add --no-playlist to just download video %s' % (playlist_id, video_id))
         webpage = self._download_webpage(url, item_id)
-        identity_token = self._search_regex(
+        identity_token = self._extract_identity_token(webpage, item_id)
-            r'\bID_TOKEN["\']\s*:\s*["\'](.+?)["\']', webpage,
-            'identity token', default=None)
         data = self._extract_yt_initial_data(item_id, webpage)
         tabs = try_get(
             data, lambda x: x['contents']['twoColumnBrowseResultsRenderer']['tabs'], list)