[youtube] extract srv[1-3] subtitle formats(#20566)

diff --git a/youtube_dl/extractor/youtube.py b/youtube_dl/extractor/youtube.py
index 886fc15914e5c8ecc08bd6eb55a04fdfee5587f9..132572c88cf26b5d0d2fa3efc33aa290b3140755 100644 (file)
--- a/youtube_dl/extractor/youtube.py
+++ b/youtube_dl/extractor/youtube.py
@@ -484,7 +484,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
         # RTMP (unnamed)
         '_rtmp': {'protocol': 'rtmp'},
     }
-    _SUBTITLE_FORMATS = ('ttml', 'vtt')
+    _SUBTITLE_FORMATS = ('srv1', 'srv2', 'srv3', 'ttml', 'vtt')
 
     _GEO_BYPASS = False