extractor/abematv: extract more metadata and add fallback for an epis…

…ode of a series

yt_dlp/extractor/abematv.py

@@ -479,6 +479,16 @@ def _real_extract(self, url):
             ondemand_types = traverse_obj(api_response, ('terms', ..., 'onDemandType'))
             if 3 not in ondemand_types:
                 self.report_warning('This is a premium-only stream. You need a premium subscription to download')
+            info.update(traverse_obj(api_response, {
+                'series': ('series', 'title'),
+                'season': ('season', 'title'),
+                'season_number': ('season', 'sequence'),
+                'episode_number': ('episode', 'number'),
+            }))
+            if not title:
+                title = traverse_obj(api_response, ('episode', 'title'))
+            if not description:
+                description = traverse_obj(api_response, ('episode', 'content'))
 
             m3u8_url = f'https://vod-abematv.akamaized.net/program/{video_id}/playlist.m3u8'
         elif video_type == 'slots':