youtube-dl https://www.youtube.com/watch?v=B7vFWy8NxIU --verbose

[avi-ram]

youtube-dl https://www.youtube.com/watch?v=B7vFWy8NxIU --verbose
[debug] System config: []
[debug] User config: []
[debug] Command-line args: ['https://www.youtube.com/watch?v=B7vFWy8NxIU', '--verbose']
[debug] Encodings: locale UTF-8, fs UTF-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2015.02.18
[debug] Python version 2.7.8 - Linux-3.16.0-30-generic-x86_64-with-Ubuntu-14.10-utopic
[debug] exe versions: avconv 11-6, avprobe 11-6, rtmpdump 2.4
[debug] Proxy map: {}
[youtube] B7vFWy8NxIU: Downloading webpage
[youtube] B7vFWy8NxIU: Extracting video information
[youtube] {22} signature length 40.41, html5 player en_US-vflKjOTVq
[youtube] B7vFWy8NxIU: Downloading js player en_US-vflKjOTVq
ERROR: Signature extraction failed: Traceback (most recent call last):
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 635, in _decrypt_signature
video_id, player_url, s
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 549, in _extract_signature_function
res = self._parse_sig_js(code)
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 613, in _parse_sig_js
initial_function = jsi.extract_function(funcname)
File "/usr/local/bin/youtube-dl/youtube_dl/jsinterp.py", line 244, in extract_function
raise ExtractorError('Could not find JS function %r' % funcname)
ExtractorError: Could not find JS function u'OF'; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; type youtube-dl -U to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
(caused by ExtractorError(u"Could not find JS function u'OF'; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; type youtube-dl -U to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.",)); please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; type youtube-dl -U to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
Traceback (most recent call last):
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 635, in _decrypt_signature
video_id, player_url, s
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 549, in _extract_signature_function
res = self._parse_sig_js(code)
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 613, in _parse_sig_js
initial_function = jsi.extract_function(funcname)
File "/usr/local/bin/youtube-dl/youtube_dl/jsinterp.py", line 244, in extract_function
raise ExtractorError('Could not find JS function %r' % funcname)
ExtractorError: Could not find JS function u'OF'; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; type youtube-dl -U to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
Traceback (most recent call last):
File "/usr/local/bin/youtube-dl/youtube_dl/YoutubeDL.py", line 643, in extract_info
ie_result = ie.extract(url)
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/common.py", line 269, in extract
return self._real_extract(url)
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1066, in _real_extract
encrypted_sig, video_id, player_url, age_gate)
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 645, in _decrypt_signature
'Signature extraction failed: ' + tb, cause=e)
ExtractorError: Signature extraction failed: Traceback (most recent call last):
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 635, in _decrypt_signature
video_id, player_url, s
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 549, in _extract_signature_function
res = self._parse_sig_js(code)
File "/usr/local/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 613, in _parse_sig_js
initial_function = jsi.extract_function(funcname)
File "/usr/local/bin/youtube-dl/youtube_dl/jsinterp.py", line 244, in extract_function
raise ExtractorError('Could not find JS function %r' % funcname)
ExtractorError: Could not find JS function u'OF'; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; type youtube-dl -U to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
(caused by ExtractorError(u"Could not find JS function u'OF'; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; type youtube-dl -U to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.",)); please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; type youtube-dl -U to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.

[phihag]

Thank you for the report. I believe this issue to be fixed in youtube-dl version 2015.02.18.1 and newer. See our FAQ if you have trouble updating.