[ie/youtube] Fix nsig fixup

test/test_youtube_signature.py

@@ -252,6 +252,10 @@ _NSIG_TESTS = [
         'https://www.youtube.com/s/player/4fcd6e4a/player_ias.vflset/en_US/base.js',
         'o_L251jm8yhZkWtBW', 'lXoxI3XvToqn6A',
     ),
+    (
+        'https://www.youtube.com/s/player/20830619/tv-player-ias.vflset/tv-player-ias.js',
+        'ir9-V6cdbCiyKxhr', '9YE85kNjZiS4',
+    ),
 ]
 
 

yt_dlp/extractor/youtube/_video.py

@@ -2215,7 +2215,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
         else:
             self.write_debug('No global array variable found in player JS')
         return argnames, re.sub(
-            rf';\s*if\s*\(\s*typeof\s+[a-zA-Z0-9_$]+\s*===?\s*(?:(["\'])undefined\1|{varname}\[\d+\])\s*\)\s*return\s+{argnames[0]};',
+            rf';\s*if\s*\(\s*typeof\s+[a-zA-Z0-9_$]+\s*===?\s*(?:(["\'])undefined\1|{re.escape(varname)}\[\d+\])\s*\)\s*return\s+{re.escape(argnames[0])};',
             ';', code)
 
     def _extract_n_function_code(self, video_id, player_url):