diff --git a/youtube_dl/extractor/generic.py b/youtube_dl/extractor/generic.py
index 51516a38a..b483eba65 100644
--- a/youtube_dl/extractor/generic.py
+++ b/youtube_dl/extractor/generic.py
@@ -1739,7 +1739,7 @@ class GenericIE(InfoExtractor):
 
         # Look for UDN embeds
         mobj = re.search(
-            r'<iframe[^>]+src="(?P<url>%s)"' % UDNEmbedIE._VALID_URL, webpage)
+            r'<iframe[^>]+src="(?P<url>%s)"' % UDNEmbedIE._PROTOCOL_RELATIVE_VALID_URL, webpage)
         if mobj is not None:
             return self.url_result(
                 compat_urlparse.urljoin(url, mobj.group('url')), 'UDNEmbed')
diff --git a/youtube_dl/extractor/udn.py b/youtube_dl/extractor/udn.py
index 2151f8338..ee35b7227 100644
--- a/youtube_dl/extractor/udn.py
+++ b/youtube_dl/extractor/udn.py
@@ -12,7 +12,8 @@ from ..compat import compat_urlparse
 
 class UDNEmbedIE(InfoExtractor):
     IE_DESC = '聯合影音'
-    _VALID_URL = r'https?://video\.udn\.com/(?:embed|play)/news/(?P<id>\d+)'
+    _PROTOCOL_RELATIVE_VALID_URL = r'//video\.udn\.com/(?:embed|play)/news/(?P<id>\d+)'
+    _VALID_URL = r'https?:' + _PROTOCOL_RELATIVE_VALID_URL
     _TESTS = [{
         'url': 'http://video.udn.com/embed/news/300040',
         'md5': 'de06b4c90b042c128395a88f0384817e',