ytdl-org/youtube-dl · error · ExtractorError

Invalid metadata XML file

Error message

Invalid metadata XML file

What it means

Raised by StanfordOpenClassRoomIE after downloading the per-video metadata XML from openclassroom.stanford.edu. The XML parsed successfully, but mdoc.findall('./title')[0] or mdoc.findall('./videoFile')[0] raised IndexError, meaning the XML root lacks a <title> or <videoFile> child. Only the IndexError is caught; a malformed (non-parsing) XML surfaces as a download/XML error instead.

Source

Thrown at youtube_dl/extractor/stanfordoc.py:46

        mobj = re.match(self._VALID_URL, url)

        if mobj.group('course') and mobj.group('video'):  # A specific video
            course = mobj.group('course')
            video = mobj.group('video')
            info = {
                'id': course + '_' + video,
                'uploader': None,
                'upload_date': None,
            }

            baseUrl = 'http://openclassroom.stanford.edu/MainFolder/courses/' + course + '/videos/'
            xmlUrl = baseUrl + video + '.xml'
            mdoc = self._download_xml(xmlUrl, info['id'])
            try:
                info['title'] = mdoc.findall('./title')[0].text
                info['url'] = baseUrl + mdoc.findall('./videoFile')[0].text
            except IndexError:
                raise ExtractorError('Invalid metadata XML file')
            return info
        elif mobj.group('course'):  # A course page
            course = mobj.group('course')
            info = {
                'id': course,
                '_type': 'playlist',
                'uploader': None,
                'upload_date': None,
            }

            coursepage = self._download_webpage(
                url, info['id'],
                note='Downloading course info page',
                errnote='Unable to download course info page')

            info['title'] = self._html_search_regex(
                r'<h1>([^<]+)</h1>', coursepage, 'title', default=info['id'])

View on GitHub (pinned to 956b8c5855)

Solutions

1. Verify the XML URL manually (http://openclassroom.stanford.edu/MainFolder/courses/<course>/videos/<video>.xml) and confirm it contains <title> and <videoFile>.
2. Find the lecture on Stanford's current hosting (e.g. edX/Stanford Online or YouTube channel).
3. If maintaining the extractor, check findall length before indexing and raise a clearer error.

Example fix

# before
info['title'] = mdoc.findall('./title')[0].text
info['url'] = baseUrl + mdoc.findall('./videoFile')[0].text
# after
titles = mdoc.findall('./title')
files = mdoc.findall('./videoFile')
if not titles or not files:
    raise ExtractorError('Invalid metadata XML file: missing title or videoFile')
info['title'] = titles[0].text
info['url'] = baseUrl + files[0].text

# Verify metadata XML has required children before extracting
import urllib.request, xml.etree.ElementTree as ET
xml = ET.fromstring(urllib.request.urlopen(xmlUrl).read())
if xml.find('./title') is None or xml.find('./videoFile') is None:
    skip('invalid metadata XML for %s' % vid)

try:
    info = ydl.extract_info(url)
except ExtractorError as e:
    if 'Invalid metadata XML file' in str(e):
        log.warning('stanfordoc metadata incomplete for %s', url)
        return None
    raise

When it happens

Trigger: Requesting a course video page whose .xml metadata file exists but has no <title> or <videoFile> element (e.g. an empty or template XML returned by the server).

Common situations: Stanford OpenClassroom is largely defunct; many course XML endpoints now return placeholder or error pages with 200 status, so this fires on most legacy playlist crawls.

Related errors

• Missing "id" field in extractor result
• Missing "title" field in extractor result
• No video formats found!
• Failed to get the video URL
• Invalid rendition field.

AI-assisted analysis of ytdl-org/youtube-dl@956b8c5855 (2026-08-14). Data as JSON: /api/errors/43b9003a956dcb16. Report an issue: GitHub.