javascript error youtube

[vendforce]

I cant downloadload or extract music from some youtube videos

youtube-dl --extract-audio --audio-format mp3 https://www.youtube.com/watch?v=JOkzV9CEjcE --verbose

[debug] System config: []
[debug] User config: []
[debug] Command-line args: ['--extract-audio', '--audio-format', 'mp3', 'https://www.youtube.com/watch?v=JOkzV9CEjcE', '--verbose']
[debug] Encodings: locale UTF-8, fs utf-8, out UTF-8, pref UTF-8
[debug] youtube-dl version 2015.11.24
[debug] Python version 3.5.1 - Linux-4.1.15-1-lts-x86_64-with-arch
[debug] exe versions: ffmpeg 2.8.4, ffprobe 2.8.4, rtmpdump 2.4
[debug] Proxy map: {}
[youtube] JOkzV9CEjcE: Downloading webpage
[youtube] JOkzV9CEjcE: Downloading video info webpage
[youtube] JOkzV9CEjcE: Extracting video information
[youtube] {22} signature length 43.43, html5 player en_US-vflrSqbyh
[youtube] JOkzV9CEjcE: Downloading player https://s.ytimg.com/yts/jsbin/player-en_US-vflrSqbyh/base.js
ERROR: Signature extraction failed: Traceback (most recent call last):
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 856, in _decrypt_signature
video_id, player_url, s
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 771, in _extract_signature_function
res = self._parse_sig_js(code)
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 834, in _parse_sig_js
initial_function = jsi.extract_function(funcname)
File "/usr/lib/python3.5/site-packages/youtube_dl/jsinterp.py", line 241, in extract_function
raise ExtractorError('Could not find JS function %r' % funcname)
youtube_dl.utils.ExtractorError: Could not find JS function 'gr'; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
(caused by ExtractorError("Could not find JS function 'gr'; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how 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; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
Traceback (most recent call last):
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 856, in _decrypt_signature
video_id, player_url, s
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 771, in _extract_signature_function
res = self._parse_sig_js(code)
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 834, in _parse_sig_js
initial_function = jsi.extract_function(funcname)
File "/usr/lib/python3.5/site-packages/youtube_dl/jsinterp.py", line 241, in extract_function
raise ExtractorError('Could not find JS function %r' % funcname)
youtube_dl.utils.ExtractorError: Could not find JS function 'gr'; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
Traceback (most recent call last):
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 856, in _decrypt_signature
video_id, player_url, s
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 771, in _extract_signature_function
res = self._parse_sig_js(code)
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 834, in _parse_sig_js
initial_function = jsi.extract_function(funcname)
File "/usr/lib/python3.5/site-packages/youtube_dl/jsinterp.py", line 241, in extract_function
raise ExtractorError('Could not find JS function %r' % funcname)
youtube_dl.utils.ExtractorError: Could not find JS function 'gr'; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/usr/lib/python3.5/site-packages/youtube_dl/YoutubeDL.py", line 663, in extract_info
ie_result = ie.extract(url)
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/common.py", line 290, in extract
return self._real_extract(url)
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 1410, in _real_extract
encrypted_sig, video_id, player_url, age_gate)
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 866, in _decrypt_signature
'Signature extraction failed: ' + tb, cause=e)
youtube_dl.utils.ExtractorError: Signature extraction failed: Traceback (most recent call last):
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 856, in _decrypt_signature
video_id, player_url, s
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 771, in _extract_signature_function
res = self._parse_sig_js(code)
File "/usr/lib/python3.5/site-packages/youtube_dl/extractor/youtube.py", line 834, in _parse_sig_js
initial_function = jsi.extract_function(funcname)
File "/usr/lib/python3.5/site-packages/youtube_dl/jsinterp.py", line 241, in extract_function
raise ExtractorError('Could not find JS function %r' % funcname)
youtube_dl.utils.ExtractorError: Could not find JS function 'gr'; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.
(caused by ExtractorError("Could not find JS function 'gr'; please report this issue on https://yt-dl.org/bug . Make sure you are using the latest version; see https://yt-dl.org/update on how 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; see https://yt-dl.org/update on how to update. Be sure to call youtube-dl with the --verbose flag and include its complete output.

[dstftw]

You are using an outdated version of youtube-dl. Read our FAQ if you have troubles updating.

[zerolagtime]

Agreed. I was having trouble too until I updated my copy via git and then recompiled.