[youtube] Recognize new locale-based player URLs (fixes #12885)

ChangeLog

+version <unreleased>
+
+Extractor
+* [youtube] Recognize new locale-based player URLs (#12885)
+
+
 version 2017.04.26
 
 Core

youtube_dl/extractor/youtube.py

@@ -963,7 +963,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
 
     def _extract_signature_function(self, video_id, player_url, example_sig):
         id_m = re.match(
-            r'.*?-(?P<id>[a-zA-Z0-9_-]+)(?:/watch_as3|/html5player(?:-new)?|/base)?\.(?P<ext>[a-z]+)$',
+            r'.*?-(?P<id>[a-zA-Z0-9_-]+)(?:/watch_as3|/html5player(?:-new)?|(?:/[a-z]{2}_[A-Z]{2})?/base)?\.(?P<ext>[a-z]+)$',
             player_url)
         if not id_m:
             raise ExtractorError('Cannot identify player %r' % player_url)