[ie/youtube] Fix `n` function name extraction for player `b12cc44b` (#10668)

Authored by: seproDev

test/test_youtube_signature.py

@@ -179,6 +179,10 @@ _NSIG_TESTS = [
         'https://www.youtube.com/s/player/20dfca59/player_ias.vflset/en_US/base.js',
         '-fLCxedkAk4LUTK2', 'O8kfRq1y1eyHGw',
     ),
+    (
+        'https://www.youtube.com/s/player/b12cc44b/player_ias.vflset/en_US/base.js',
+        'keLa5R2U00sR9SQK', 'N1OGyujjEwMnLw',
+    ),
 ]
 
 

yt_dlp/extractor/youtube.py

@@ -3180,6 +3180,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
         # *  b=String.fromCharCode(110),c=a.get(b))&&c=narray[idx](c)
         # *  a.D&&(b="nn"[+a.D],c=a.get(b))&&(c=narray[idx](c),a.set(b,c),narray.length||nfunc("")
         # *  a.D&&(PL(a),b=a.j.n||null)&&(b=narray[0](b),a.set("n",b),narray.length||nfunc("")
+        # *  a.D&&(b="nn"[+a.D],vL(a),c=a.j[b]||null)&&(c=narray[idx](c),a.set(b,c),narray.length||nfunc("")
         funcname, idx = self._search_regex(
             r'''(?x)
             (?:
@@ -3187,7 +3188,13 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
                 (?:
                     b=String\.fromCharCode\(110\)|
                     (?P<str_idx>[a-zA-Z0-9_$.]+)&&\(b="nn"\[\+(?P=str_idx)\]
-                ),c=a\.get\(b\)\)&&\(c=|
+                )
+                (?:
+                    ,[a-zA-Z0-9_$]+\(a\))?,c=a\.
+                    (?:
+                        get\(b\)|
+                        [a-zA-Z0-9_$]+\[b\]\|\|null
+                    )\)&&\(c=|
                 \b(?P<var>[a-zA-Z0-9_$]+)=
             )(?P<nfunc>[a-zA-Z0-9_$]+)(?:\[(?P<idx>\d+)\])?\([a-zA-Z]\)
             (?(var),[a-zA-Z0-9_$]+\.set\("n"\,(?P=var)\),(?P=nfunc)\.length)''',