+        for cc_kind in ('subtitles', 'automatic_captions'):
+            cc = info_dict.get(cc_kind)
+            if cc:
+                for _, subtitle in cc.items():
+                    for subtitle_format in subtitle:
+                        if subtitle_format.get('url'):
+                            subtitle_format['url'] = sanitize_url(subtitle_format['url'])
+                        if subtitle_format.get('ext') is None:
+                            subtitle_format['ext'] = determine_ext(subtitle_format['url']).lower()
+
+        automatic_captions = info_dict.get('automatic_captions')