diff --git a/youtube_dl/extractor/ard.py b/youtube_dl/extractor/ard.py
index 915f8862e..ef73d5a93 100644
--- a/youtube_dl/extractor/ard.py
+++ b/youtube_dl/extractor/ard.py
@@ -5,6 +5,7 @@
 
 from .common import InfoExtractor
 from .generic import GenericIE
+from ..compat import compat_str
 from ..utils import (
     determine_ext,
     ExtractorError,
@@ -126,6 +127,8 @@ def _extract_formats(self, media_info, video_id):
                 quality = stream.get('_quality')
                 server = stream.get('_server')
                 for stream_url in stream_urls:
+                    if not isinstance(stream_url, compat_str) or '//' not in stream_url:
+                        continue
                     ext = determine_ext(stream_url)
                     if quality != 'auto' and ext in ('f4m', 'm3u8'):
                         continue
@@ -146,13 +149,11 @@ def _extract_formats(self, media_info, video_id):
                                 'play_path': stream_url,
                                 'format_id': 'a%s-rtmp-%s' % (num, quality),
                             }
-                        elif stream_url.startswith('http'):
+                        else:
                             f = {
                                 'url': stream_url,
                                 'format_id': 'a%s-%s-%s' % (num, ext, quality)
                             }
-                        else:
-                            continue
                         m = re.search(r'_(?P<width>\d+)x(?P<height>\d+)\.mp4$', stream_url)
                         if m:
                             f.update({