[youtube] Skip WebVTT in DASH manifest (#5297)

youtube_dl/extractor/youtube.py

@@ -788,10 +788,16 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
             errnote='Could not download DASH manifest')
 
         formats = []
-        for r in dash_doc.findall('.//{urn:mpeg:DASH:schema:MPD:2011}Representation'):
+        for a in dash_doc.findall('.//{urn:mpeg:DASH:schema:MPD:2011}AdaptationSet'):
+            mime_type = a.attrib.get('mimeType')
+            for r in a.findall('{urn:mpeg:DASH:schema:MPD:2011}Representation'):
                 url_el = r.find('{urn:mpeg:DASH:schema:MPD:2011}BaseURL')
                 if url_el is None:
                     continue
+                if mime_type == 'text/vtt':
+                    # TODO implement WebVTT downloading
+                    pass
+                elif mime_type.startswith('audio/') or mime_type.startswith('video/'):
                     format_id = r.attrib['id']
                     video_url = url_el.text
                     filesize = int_or_none(url_el.attrib.get('{http://youtube.com/yt/2012/10/10}contentLength'))
@@ -815,6 +821,8 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
                         formats.append(full_info)
                     else:
                         existing_format.update(f)
+                else:
+                    self.report_warning('Unknown MIME type %s in DASH manifest' % mime_type)
         return formats
 
     def _real_extract(self, url):