xubuntu 12.04 from official repository: doesn't work

[unixman72]

unixman@malphas:/Videos$ python --version
Python 2.7.3
unixman@malphas:/Videos$ youtube-dl -t "http://www.youtube.com/watch?feature=player_embedded&v=a4BKuH8mqw4"
[youtube] Setting language
[youtube] a4BKuH8mqw4: Downloading video webpage
[youtube] a4BKuH8mqw4: Downloading video info webpage
[youtube] a4BKuH8mqw4: Extracting video information
Traceback (most recent call last):
File "/usr/bin/youtube-dl", line 4645, in
main()
File "/usr/bin/youtube-dl", line 4636, in main
_real_main()
File "/usr/bin/youtube-dl", line 4620, in _real_main
retcode = fd.download(all_urls)
File "/usr/bin/youtube-dl", line 869, in download
ie.extract(url)
File "/usr/bin/youtube-dl", line 1135, in extract
return self._real_extract(url)
File "/usr/bin/youtube-dl", line 1406, in _real_extract
url_map = dict((ud['itag'][0], ud['url'][0] + '&signature=' + ud['sig'][0]) for ud in url_data)
File "/usr/bin/youtube-dl", line 1406, in
url_map = dict((ud['itag'][0], ud['url'][0] + '&signature=' + ud['sig'][0]) for ud in url_data)
KeyError: 'sig'

[phihag]

There's little we can do about that, the version of youtube-dl in Ubuntu 12.04 is 2012.02.27. Since then, YouTube has significantly modified its API at least twice.

What you can do is use an up-to-date version of youtube-dl, either by typing sudo youtube-dl -U once to use our built-in updating mechanism, or by pinning youtube-dl to a more modern disitribution, or by installing youtube-dl by hand instead of via a package manager.