[youtube] Extract chapters

youtube_dl/extractor/youtube.py

@@ -1257,6 +1257,35 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
         url = 'https://www.youtube.com/annotations_invideo?features=1&legacy=1&video_id=%s' % video_id
         return self._download_webpage(url, video_id, note='Searching for annotations.', errnote='Unable to download video annotations.')
 
+    @staticmethod
+    def _extract_chapters(description, duration):
+        if not description:
+            return None
+        chapter_lines = re.findall(
+            r'(?:^|<br\s*/>)([^<]*<a[^>]+onclick=["\']yt\.www\.watch\.player\.seekTo[^>]+>(\d{1,2}:\d{1,2}(?::\d{1,2})?)</a>[^>]*)(?=$|<br\s*/>)',
+            description)
+        if not chapter_lines:
+            return None
+        chapters = []
+        for next_num, (chapter_line, time_point) in enumerate(
+                chapter_lines, start=1):
+            start_time = parse_duration(time_point)
+            if start_time is None:
+                continue
+            end_time = (duration if next_num == len(chapter_lines)
+                        else parse_duration(chapter_lines[next_num][1]))
+            if end_time is None:
+                continue
+            chapter_title = re.sub(
+                r'<a[^>]+>[^<]+</a>', '', chapter_line).strip(' \t-')
+            chapter_title = re.sub(r'\s+', ' ', chapter_title)
+            chapters.append({
+                'start_time': start_time,
+                'end_time': end_time,
+                'title': chapter_title,
+            })
+        return chapters
+
     def _real_extract(self, url):
         url, smuggled_data = unsmuggle_url(url, {})
 
@@ -1399,9 +1428,9 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
             video_title = '_'
 
         # description
-        video_description = get_element_by_id("eow-description", video_webpage)
+        description_original = video_description = get_element_by_id("eow-description", video_webpage)
         if video_description:
-            video_description = re.sub(r'''(?x)
+            description_original = video_description = re.sub(r'''(?x)
                 <a\s+
                     (?:[a-zA-Z-]+="[^"]*"\s+)*?
                     (?:title|href)="([^"]+)"\s+
@@ -1558,6 +1587,8 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
         if self._downloader.params.get('writeannotations', False):
             video_annotations = self._extract_annotations(video_id)
 
+        chapters = self._extract_chapters(description_original, video_duration)
+
         if 'conn' in video_info and video_info['conn'][0].startswith('rtmp'):
             self.report_rtmp_download()
             formats = [{
@@ -1790,6 +1821,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
             'duration': video_duration,
             'age_limit': 18 if age_gate else 0,
             'annotations': video_annotations,
+            'chapters': chapters,
             'webpage_url': proto + '://www.youtube.com/watch?v=%s' % video_id,
             'view_count': view_count,
             'like_count': like_count,