Youtube backend fails on some videos

[gsilvis]

It seems to only happen on music

[debug] System config: []
[debug] User config: []
[debug] Command-line args: ['https://www.youtube.com/watch?v=hiwi7d0f91Y', '--verbose']
[debug] Encodings: locale UTF-8, fs UTF-8, out None, pref UTF-8
[debug] youtube-dl version 2014.08.05
[debug] Python version 2.7.9 - Linux-3.16.0-4-amd64-x86_64-with-debian-8.1
[debug] Proxy map: {}
[youtube] Setting language
[youtube] hiwi7d0f91Y: Downloading webpage
[youtube] hiwi7d0f91Y: Downloading video info webpage
[youtube] hiwi7d0f91Y: Extracting video information
[youtube] hiwi7d0f91Y: Encrypted signatures detected.
[youtube] {43} signature length 41.42, html5 player en_US-vflVsMRd_
[youtube] hiwi7d0f91Y: Downloading js player vflVsMRd_
ERROR: Signature extraction failed: Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 479, in _decrypt_signature
    video_id, player_url, s
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 383, in _extract_signature_function
    res = self._parse_sig_js(code)
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 454, in _parse_sig_js
    u'Initial JS player signature function name')
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/common.py", line 391, in _search_regex
    raise RegexNotFoundError(u'Unable to extract %s' % _name)
RegexNotFoundError: Unable to extract Initial JS player signature function name; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type  youtube-dl -U  to update.
; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type  youtube-dl -U  to update.
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 479, in _decrypt_signature
    video_id, player_url, s
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 383, in _extract_signature_function
    res = self._parse_sig_js(code)
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 454, in _parse_sig_js
    u'Initial JS player signature function name')
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/common.py", line 391, in _search_regex
    raise RegexNotFoundError(u'Unable to extract %s' % _name)
RegexNotFoundError: Unable to extract Initial JS player signature function name; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type  youtube-dl -U  to update.
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/youtube_dl/YoutubeDL.py", line 516, in extract_info
    ie_result = ie.extract(url)
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/common.py", line 170, in extract
    return self._real_extract(url)
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 860, in _real_extract
    encrypted_sig, video_id, player_url, age_gate)
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 489, in _decrypt_signature
    u'Signature extraction failed: ' + tb, cause=e)
ExtractorError: Signature extraction failed: Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 479, in _decrypt_signature
    video_id, player_url, s
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 383, in _extract_signature_function
    res = self._parse_sig_js(code)
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/youtube.py", line 454, in _parse_sig_js
    u'Initial JS player signature function name')
  File "/usr/lib/python2.7/dist-packages/youtube_dl/extractor/common.py", line 391, in _search_regex
    raise RegexNotFoundError(u'Unable to extract %s' % _name)
RegexNotFoundError: Unable to extract Initial JS player signature function name; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type  youtube-dl -U  to update.
; please report this issue on https://yt-dl.org/bug . Be sure to call youtube-dl with the --verbose flag and include its complete output. Make sure you are using the latest version; type  youtube-dl -U  to update.

[yan12125]

You need to update youtube-dl. Current version is 2015.07.07 while yours is 2014.08.15. Have a look at this FAQ entry if you have any problem.

[gsilvis]

The hash -r in the installation instructions is important, it would seem. Thanks for the help.