[youtube] Add a pseudo format for rtmp videos (#2123)

youtube_dl/extractor/youtube.py

@@ -213,6 +213,9 @@ class YoutubeIE(YoutubeBaseInfoExtractor, SubtitlesInfoExtractor):
         # Dash webm audio
         '171': {'ext': 'webm', 'vcodec': 'none', 'format_note': 'DASH webm audio', 'abr': 48, 'preference': -50},
         '172': {'ext': 'webm', 'vcodec': 'none', 'format_note': 'DASH webm audio', 'abr': 256, 'preference': -50},
+
+        # RTMP (unnamed)
+        '_rtmp': {'protocol': 'rtmp'},
     }
 
     IE_NAME = u'youtube'
@@ -1273,7 +1276,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor, SubtitlesInfoExtractor):
 
         if 'conn' in video_info and video_info['conn'][0].startswith('rtmp'):
             self.report_rtmp_download()
-            video_url_list = [(None, video_info['conn'][0])]
+            video_url_list = [('_rtmp', video_info['conn'][0])]
         elif len(video_info.get('url_encoded_fmt_stream_map', [])) >= 1 or len(video_info.get('adaptive_fmts', [])) >= 1:
             encoded_url_map = video_info.get('url_encoded_fmt_stream_map', [''])[0] + ',' + video_info.get('adaptive_fmts',[''])[0]
             if 'rtmpe%3Dyes' in encoded_url_map: