+        stream_url = asset.get('stream_url') or asset.get('streamUrl')
+        if stream_url:
+            youtube_url = self._search_regex(
+                r'(https?://www\.youtube\.com/watch\?v=.*)', stream_url, 'youtube URL', default=None)
+            if youtube_url:
+                return self.url_result(youtube_url, 'Youtube')
+
+        video_id = compat_str(asset['id'])
+        thumbnail = asset.get('thumbnail_url') or asset.get('thumbnailUrl')
+        duration = float_or_none(asset.get('data', {}).get('duration'))
+
+        formats = []
+
+        def extract_output_format(src):
+            return {
+                'url': src['url'],
+                'format_id': '%sp' % (src.get('height') or format_id),
+                'width': int_or_none(src.get('width')),
+                'height': int_or_none(src.get('height')),
+                'vbr': int_or_none(src.get('video_bitrate_in_kbps')),
+                'vcodec': src.get('video_codec'),
+                'fps': int_or_none(src.get('frame_rate')),
+                'abr': int_or_none(src.get('audio_bitrate_in_kbps')),
+                'acodec': src.get('audio_codec'),
+                'asr': int_or_none(src.get('audio_sample_rate')),
+                'tbr': int_or_none(src.get('total_bitrate_in_kbps')),
+                'filesize': int_or_none(src.get('file_size_in_bytes')),
+            }
+
+        outputs = asset.get('data', {}).get('outputs')
+        if not isinstance(outputs, dict):
+            outputs = {}
+
+        def add_output_format_meta(f, key):
+            output = outputs.get(key)
+            if isinstance(output, dict):
+                output_format = extract_output_format(output)
+                output_format.update(f)
+                return output_format
+            return f
+
+        download_urls = asset.get('download_urls')
+        if isinstance(download_urls, dict):
+            video = download_urls.get('Video')
+            if isinstance(video, list):
+                for format_ in video:
+                    video_url = format_.get('file')
+                    if not video_url:
+                        continue
+                    format_id = format_.get('label')
+                    f = {
+                        'url': format_['file'],
+                        'format_id': '%sp' % format_id,
+                        'height': int_or_none(format_id),
+                    }
+                    if format_id:
+                        # Some videos contain additional metadata (e.g.
+                        # https://www.udemy.com/ios9-swift/learn/#/lecture/3383208)
+                        f = add_output_format_meta(f, format_id)
+                    formats.append(f)
+
+        view_html = lecture.get('view_html')
+        if view_html:
+            view_html_urls = set()
+            for source in re.findall(r'<source[^>]+>', view_html):
+                attributes = extract_attributes(source)
+                src = attributes.get('src')
+                if not src:
+                    continue
+                res = attributes.get('data-res')
+                height = int_or_none(res)
+                if src in view_html_urls:
+                    continue
+                view_html_urls.add(src)
+                if attributes.get('type') == 'application/x-mpegURL' or determine_ext(src) == 'm3u8':
+                    m3u8_formats = self._extract_m3u8_formats(
+                        src, video_id, 'mp4', entry_protocol='m3u8_native',
+                        m3u8_id='hls', fatal=False)
+                    for f in m3u8_formats:
+                        m = re.search(r'/hls_(?P<height>\d{3,4})_(?P<tbr>\d{2,})/', f['url'])
+                        if m:
+                            if not f.get('height'):
+                                f['height'] = int(m.group('height'))
+                            if not f.get('tbr'):
+                                f['tbr'] = int(m.group('tbr'))
+                    formats.extend(m3u8_formats)
+                else:
+                    formats.append(add_output_format_meta({
+                        'url': src,
+                        'format_id': '%dp' % height if height else None,
+                        'height': height,
+                    }, res))
+
+        self._sort_formats(formats, field_preference=('height', 'width', 'tbr', 'format_id'))