youtube-dl 'http://www.c-span.org/video/standalone/?323622-1/lawrence-lessig-campaign-finance' fails

[MBRosenthal]

I'm trying to use youtube-dl, version 2015.09.03 under OS X 10.8.5 to download a video from CSpan, but instead of downloading the video, youtube-dl produces an error. CSpan is listed as one of the sites supported by youtube-dl (http://rg3.github.io/youtube-dl contains a link labeled "more sites" which points to http://rg3.github.io/youtube-dl/supportedsites.html. That page lists CSpan.) Here are the details:

I just downloaded and installed youtube-dl by doing the following:

I navigated to http://rg3.github.io/youtube-dl/download.html to download youtube-dl. That page says:

To install it right away for all UNIX users (Linux, OS X, etc.), type:

    sudo curl https://yt-dl.org/downloads/2015.09.03/youtube-dl -o /usr/local/bin/youtube-dl
    sudo chmod a+rx /usr/local/bin/youtube-dl

I ran those commands. I then verified that the latest version of youtube-dl is installed:

bash-3.2$ youtube-dl -U
youtube-dl is up-to-date (2015.09.03)

I then ran youtube-dl as follows:

youtube-dl 'http://www.c-span.org/video/standalone/?323622-1/lawrence-lessig-campaign-finance'

It complained:

[generic] lawrence-lessig-campaign-finance: Requesting header
WARNING: Falling back on generic information extractor.
[generic] lawrence-lessig-campaign-finance: Downloading webpage
[generic] lawrence-lessig-campaign-finance: Extracting information
ERROR: Unsupported URL: http://www.c-span.org/video/standalone/?323622-1/lawrence-lessig-campaign-finance

I reran youtube-dl with the --verbose flag. Below are the commands I ran and the output from those commands.

bash-3.2$ youtube-dl --verbose 'http://www.c-span.org/video/standalone/?323622-1/lawrence-lessig-campaign-finance'
[debug] System config: []
[debug] User config: []
[debug] Command-line args: [u'--verbose', u'http://www.c-span.org/video/standalone/?323622-1/lawrence-lessig-campaign-finance']
[debug] Encodings: locale US-ASCII, fs utf-8, out US-ASCII, pref US-ASCII
[debug] youtube-dl version 2015.09.03
[debug] Python version 2.7.2 - Darwin-12.5.0-x86_64-i386-64bit
[debug] exe versions: none
[debug] Proxy map: {}
[generic] lawrence-lessig-campaign-finance: Requesting header
WARNING: Falling back on generic information extractor.
[generic] lawrence-lessig-campaign-finance: Downloading webpage
[generic] lawrence-lessig-campaign-finance: Extracting information
ERROR: Unsupported URL: http://www.c-span.org/video/standalone/?323622-1/lawrence-lessig-campaign-finance
Traceback (most recent call last):
  File "/usr/local/bin/youtube-dl/youtube_dl/extractor/generic.py", line 1222, in _real_extract
    doc = parse_xml(webpage)
  File "/usr/local/bin/youtube-dl/youtube_dl/utils.py", line 1599, in parse_xml
    tree = xml.etree.ElementTree.XML(s.encode('utf-8'), **kwargs)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/xml/etree/ElementTree.py", line 1282, in XML
    parser.feed(text)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/xml/etree/ElementTree.py", line 1624, in feed
    self._raiseerror(v)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/xml/etree/ElementTree.py", line 1488, in _raiseerror
    raise err
ParseError: not well-formed (invalid token): line 19, column 37
Traceback (most recent call last):
  File "/usr/local/bin/youtube-dl/youtube_dl/YoutubeDL.py", line 655, in extract_info
    ie_result = ie.extract(url)
  File "/usr/local/bin/youtube-dl/youtube_dl/extractor/common.py", line 287, in extract
    return self._real_extract(url)
  File "/usr/local/bin/youtube-dl/youtube_dl/extractor/generic.py", line 1820, in _real_extract
    raise UnsupportedError(url)
UnsupportedError: Unsupported URL: http://www.c-span.org/video/standalone/?323622-1/lawrence-lessig-campaign-finance

[MBRosenthal]

I just discovered how to get it working. I'd given youtube-dl an argument that points to the video rather than the webpage that contains the video plus all of C-Span's additional content (header, footer, description, etc.) Apparently youtube-dl searches for a particular node in the HTML tree to find the link to the video. Since the page at the URL I initially gave it (http://www.c-span.org/video/standalone/?323622-1/lawrence-lessig-campaign-finance) doesn't contain that HTML, it couldn't find the link to the video. When I instead ran youtube-dl 'http://www.c-span.org/video/?323622-1/lawrence-lessig-campaign-finance', it downloaded without a problem. In case the difference in the URLs is not obvious, the former contains the string "standalone". The latter does not.