[prosiebensat1] Extend _VALID_URL (closes #15520)

diff --git a/youtube_dl/extractor/prosiebensat1.py b/youtube_dl/extractor/prosiebensat1.py
index 48757fd4f71de7ee0c2682f818f3976d72080741..7efff45662906b7a861ba6e22fc1a840f82635f6 100644 (file)
--- a/youtube_dl/extractor/prosiebensat1.py
+++ b/youtube_dl/extractor/prosiebensat1.py
@@ -129,6 +129,7 @@ class ProSiebenSat1IE(ProSiebenSat1BaseIE):
                     https?://
                         (?:www\.)?
                         (?:
+                            (?:beta\.)?
                             (?:
                                 prosieben(?:maxx)?|sixx|sat1(?:gold)?|kabeleins(?:doku)?|the-voice-of-germany|7tv|advopedia
                             )\.(?:de|at|ch)|