[youtube] Adapt to new automatic captions rendition (closes #13467)

youtube_dl/extractor/youtube.py

@@ -1269,37 +1269,57 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
                     sub_lang_list[sub_lang] = sub_formats
                 return sub_lang_list
 
+            def make_captions(sub_url, sub_langs):
+                parsed_sub_url = compat_urllib_parse_urlparse(sub_url)
+                caption_qs = compat_parse_qs(parsed_sub_url.query)
+                captions = {}
+                for sub_lang in sub_langs:
+                    sub_formats = []
+                    for ext in self._SUBTITLE_FORMATS:
+                        caption_qs.update({
+                            'tlang': [sub_lang],
+                            'fmt': [ext],
+                        })
+                        sub_url = compat_urlparse.urlunparse(parsed_sub_url._replace(
+                            query=compat_urllib_parse_urlencode(caption_qs, True)))
+                        sub_formats.append({
+                            'url': sub_url,
+                            'ext': ext,
+                        })
+                    captions[sub_lang] = sub_formats
+                return captions
+
+            # New captions format as of 22.06.2017
+            player_response = args.get('player_response')
+            if player_response and isinstance(player_response, compat_str):
+                player_response = self._parse_json(
+                    player_response, video_id, fatal=False)
+                if player_response:
+                    renderer = player_response['captions']['playerCaptionsTracklistRenderer']
+                    base_url = renderer['captionTracks'][0]['baseUrl']
+                    sub_lang_list = []
+                    for lang in renderer['translationLanguages']:
+                        lang_code = lang.get('languageCode')
+                        if lang_code:
+                            sub_lang_list.append(lang_code)
+                    return make_captions(base_url, sub_lang_list)
+
             # Some videos don't provide ttsurl but rather caption_tracks and
             # caption_translation_languages (e.g. 20LmZk1hakA)
+            # Does not used anymore as of 22.06.2017
             caption_tracks = args['caption_tracks']
             caption_translation_languages = args['caption_translation_languages']
             caption_url = compat_parse_qs(caption_tracks.split(',')[0])['u'][0]
-            parsed_caption_url = compat_urllib_parse_urlparse(caption_url)
+            sub_lang_list = []
-            caption_qs = compat_parse_qs(parsed_caption_url.query)
-
-            sub_lang_list = {}
             for lang in caption_translation_languages.split(','):
                 lang_qs = compat_parse_qs(compat_urllib_parse_unquote_plus(lang))
                 sub_lang = lang_qs.get('lc', [None])[0]
-                if not sub_lang:
+                if sub_lang:
-                    continue
+                    sub_lang_list.append(sub_lang)
-                sub_formats = []
+            return make_captions(caption_url, sub_lang_list)
-                for ext in self._SUBTITLE_FORMATS:
-                    caption_qs.update({
-                        'tlang': [sub_lang],
-                        'fmt': [ext],
-                    })
-                    sub_url = compat_urlparse.urlunparse(parsed_caption_url._replace(
-                        query=compat_urllib_parse_urlencode(caption_qs, True)))
-                    sub_formats.append({
-                        'url': sub_url,
-                        'ext': ext,
-                    })
-                sub_lang_list[sub_lang] = sub_formats
-            return sub_lang_list
         # An extractor error can be raise by the download process if there are
         # no automatic captions but there are subtitles
-        except (KeyError, ExtractorError):
+        except (KeyError, IndexError, ExtractorError):
             self._downloader.report_warning(err_msg)
             return {}