[extractor/common] Simplify _extract_m3u8_formats

youtube_dl/extractor/common.py

@@ -1201,8 +1201,8 @@ class InfoExtractor(object):
                 'protocol': entry_protocol,
                 'preference': preference,
             }]
-        last_info = None
-        last_media = None
+        last_info = {}
+        last_media = {}
         for line in m3u8_doc.splitlines():
             if line.startswith('#EXT-X-STREAM-INF:'):
                 last_info = parse_m3u8_attributes(line)
@@ -1232,17 +1232,13 @@ class InfoExtractor(object):
             elif line.startswith('#') or not line.strip():
                 continue
             else:
-                if last_info is None:
-                    formats.append({'url': format_url(line)})
-                    continue
                 tbr = int_or_none(last_info.get('AVERAGE-BANDWIDTH') or last_info.get('BANDWIDTH'), scale=1000)
                 format_id = []
                 if m3u8_id:
                     format_id.append(m3u8_id)
-                last_media_name = last_media.get('NAME') if last_media else None
                 # Despite specification does not mention NAME attribute for
                 # EXT-X-STREAM-INF it still sometimes may be present
-                stream_name = last_info.get('NAME') or last_media_name
+                stream_name = last_info.get('NAME') or last_media.get('NAME')
                 # Bandwidth of live streams may differ over time thus making
                 # format_id unpredictable. So it's better to keep provided
                 # format_id intact.
@@ -1275,6 +1271,7 @@ class InfoExtractor(object):
                 f.update(parse_codecs(last_info.get('CODECS')))
                 formats.append(f)
                 last_info = {}
+                last_media = {}
         return formats
 
     @staticmethod