[brightcove] Make _VALID_URL less greedy and check for empty URLs (#3541)

youtube_dl/extractor/brightcove.py

@@ -23,7 +23,7 @@ from ..utils import (
 
 
 class BrightcoveIE(InfoExtractor):
-    _VALID_URL = r'https?://.*brightcove\.com/(services|viewer).*\?(?P<query>.*)'
+    _VALID_URL = r'https?://.*brightcove\.com/(services|viewer).*?\?(?P<query>.*)'
     _FEDERATED_URL_TEMPLATE = 'http://c.brightcove.com/services/viewer/htmlFederated?%s'
 
     _TESTS = [
@@ -260,6 +260,8 @@ class BrightcoveIE(InfoExtractor):
             formats = []
             for rend in renditions:
                 url = rend['defaultURL']
+                if not url:
+                    continue
                 if rend['remote']:
                     # This type of renditions are served through akamaihd.net,
                     # but they don't use f4m manifests