youtube-dl version confusion [Was: Unsupported JS expression u'$y(a,7)']

[sarkiaponius]

No description provided.

[sarkiaponius]

Several videos show this issue, but others do not.
Here is the output

michele@debian:~$ youtube-dl --verbose "http://www.youtube.com/watch?feature=player_detailpage&v=sfR_HWMzgyc"
[debug] System config: []
[debug] User config: []
[debug] Command-line args: ['--verbose', 'http://www.youtube.com/watch?feature=player_detailpage&v=sfR_HWMzgyc']
[debug] youtube-dl version 2013.11.22.2
[debug] Python version 2.7.3 - Linux-3.2.0-4-amd64-x86_64-with-debian-7.3
[debug] Proxy map: {}
[youtube] Setting language
[youtube] sfR_HWMzgyc: Downloading video webpage
[youtube] sfR_HWMzgyc: Downloading video info webpage
[youtube] sfR_HWMzgyc: Extracting video information
[youtube] sfR_HWMzgyc: Encrypted signatures detected.
[youtube] encrypted signature length 90 (46.43), itag 43, html5 player vfle-mVwz
[youtube] sfR_HWMzgyc: Downloading js player mVwz
WARNING: Writing cache to u'/home/michele/.cache/youtube-dl/youtube-sigfuncs/js_mVwz_90.json' failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 453, in _extract_signature_function
cache_res = res(test_string)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 90 (46.43), itag 18, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 90 (46.43), itag 5, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 90 (46.43), itag 36, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 90 (46.43), itag 17, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 86 (45.40), itag 135, html5 player vfle-mVwz
[youtube] sfR_HWMzgyc: Downloading js player mVwz
WARNING: Writing cache to u'/home/michele/.cache/youtube-dl/youtube-sigfuncs/js_mVwz_86.json' failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 453, in _extract_signature_function
cache_res = res(test_string)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 86 (45.40), itag 134, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 86 (45.40), itag 133, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 86 (45.40), itag 160, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 86 (45.40), itag 140, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 86 (45.40), itag 171, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 90 (46.43), itag 135, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 90 (46.43), itag 134, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 90 (46.43), itag 133, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 90 (46.43), itag 160, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 90 (46.43), itag 140, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
[youtube] encrypted signature length 90 (46.43), itag 171, html5 player vfle-mVwz
WARNING: Automatic signature extraction failed: Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 1046, in _decrypt_signature
return func(s)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 614, in
return lambda s: initial_function([s])
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 609, in resf
res = interpret_statement(stmt, local_vars)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 544, in interpret_statement
v = interpret_expression(expr, local_vars, allow_recursion)
File "/opt/bin/youtube-dl/youtube_dl/extractor/youtube.py", line 597, in interpret_expression
raise ExtractorError(u'Unsupported JS expression %r' % expr)
ExtractorError: Unsupported JS expression u'$y(a,7)'; 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.

WARNING: Warning: Falling back to static signature algorithm
ERROR: unable to download video data: HTTP Error 403: Forbidden
Traceback (most recent call last):
File "/opt/bin/youtube-dl/youtube_dl/YoutubeDL.py", line 758, in process_info
success = self.fd._do_download(filename, info_dict)
File "/opt/bin/youtube-dl/youtube_dl/FileDownloader.py", line 469, in _do_download
data = compat_urllib_request.urlopen(request)
File "/usr/lib/python2.7/urllib2.py", line 127, in urlopen
return _opener.open(url, data, timeout)
File "/usr/lib/python2.7/urllib2.py", line 407, in open
response = meth(req, response)
File "/usr/lib/python2.7/urllib2.py", line 520, in http_response
'http', request, response, code, msg, hdrs)
File "/usr/lib/python2.7/urllib2.py", line 445, in error
return self._call_chain(_args)
File "/usr/lib/python2.7/urllib2.py", line 379, in _call_chain
result = func(_args)
File "/usr/lib/python2.7/urllib2.py", line 528, in http_error_default
raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
HTTPError: HTTP Error 403: Forbidden

[sarkiaponius]

Sorry, it's my first issue!

[phihag]

You are using an outdated version of youtube-dl. Type sudo youtube-dl -U to update to version 2014.02.04.1 or newer, where this problem has been fixed.

[sarkiaponius]

I'm using version 2014.02.05. I ran youtube-dl -U several times as root, and always got:
youtube-dl is up-to-date (2014.02.05)
Thank you anyway for your answer.

[phihag]

@sarkiaponius Maybe you have installed youtube-dl as root separately? In any case, you can call youtube-dl --version to see the version of youtube-dl. The above output is from an older version of youtube-dl. Can you post the full output you get with youtube-dl 2014.02.05?

[sarkiaponius]

You're right, there is some confusion with version. As user "root" or "michele" my version is 2013.11.22.2, while as user "andrea" is the 2014.02.06.2. Also, the former users use /opt/bin/youtube-dl, while the latter use ~/bin/youtube-dl.
I just copied the last version into /opt/bin/ and now it seems to work. I just hope it will keep up to date.
Maybe the issue can be closed.
I thank you very much for your kind help.
Best regards.