[vrt] Prefix format ids

youtube_dl/extractor/vrt.py

@@ -73,11 +73,11 @@ class VRTIE(InfoExtractor):
         if mobj:
             formats.extend(self._extract_m3u8_formats(
                 '%s/%s' % (mobj.group('server'), mobj.group('path')),
-                video_id, 'mp4'))
+                video_id, 'mp4', m3u8_id='hls'))
         mobj = re.search(r'data-video-src="(?P<src>[^"]+)"', webpage)
         if mobj:
             formats.extend(self._extract_f4m_formats(
-                '%s/manifest.f4m' % mobj.group('src'), video_id))
+                '%s/manifest.f4m' % mobj.group('src'), video_id, f4m_id='hds'))
         self._sort_formats(formats)
 
         title = self._og_search_title(webpage)