Remove warning for videos with an empty title

yt_dlp/YoutubeDL.py

@@ -2335,12 +2335,16 @@ class YoutubeDL:
         # TODO: move sanitization here
         if is_video:
             # playlists are allowed to lack "title"
-            info_dict['fulltitle'] = info_dict.get('title')
-            if 'title' not in info_dict:
+            title = info_dict.get('title', NO_DEFAULT)
+            if title is NO_DEFAULT:
                 raise ExtractorError('Missing "title" field in extractor result',
                                      video_id=info_dict['id'], ie=info_dict['extractor'])
-            elif not info_dict.get('title'):
-                self.report_warning('Extractor failed to obtain "title". Creating a generic title instead')
+            info_dict['fulltitle'] = title
+            if not title:
+                if title == '':
+                    self.write_debug('Extractor gave empty title. Creating a generic title')
+                else:
+                    self.report_warning('Extractor failed to obtain "title". Creating a generic title instead')
                 info_dict['title'] = f'{info_dict["extractor"].replace(":", "-")} video #{info_dict["id"]}'
 
         if info_dict.get('duration') is not None:

yt_dlp/extractor/common.py

@@ -103,7 +103,9 @@ class InfoExtractor:
     For a video, the dictionaries must include the following fields:
 
     id:             Video identifier.
-    title:          Video title, unescaped.
+    title:          Video title, unescaped. Set to an empty string if video has
+                    no title as opposed to "None" which signifies that the
+                    extractor failed to obtain a title
 
     Additionally, it must contain either a formats entry or a url one: