[SOLVED] ERROR: unable to download video

when you download with youtube-dl, you get an error as this :

[youtube] Setting language
[youtube] pgEFfZOV9GQ: Downloading video webpage
[youtube] pgEFfZOV9GQ: Downloading video info webpage
[youtube] pgEFfZOV9GQ: Extracting video information
[youtube] pgEFfZOV9GQ: Encrypted signatures detected.

ERROR: unable to download video

then you try to solve by this command : 

sudo youtube-dl -U

you just get this message : 

It looks like you installed youtube-dl with a package manager, pip, setup.py or a tarball. Please use that to update.

well, the solution is :

sudo pip install --upgrade youtube-dl

Downloading/unpacking youtube-dl from https://pypi.python.org/packages/source/y/youtube_dl/youtube_dl-2014.02.26.tar.gz#md5=941720c118544cb0d00dde072b8667f7

  Downloading youtube_dl-2014.02.26.tar.gz (311kB): 311kB downloaded

  Running setup.py egg_info for package youtube-dl

    

Installing collected packages: youtube-dl

  Found existing installation: youtube-dl 2013.08.29

    Uninstalling youtube-dl:

      Successfully uninstalled youtube-dl

  Running setup.py install for youtube-dl

    

    Installing youtube-dl script to /usr/local/bin

Successfully installed youtube-dl

Cleaning up...

then everything will run properly.

..show all:.

.

when you download with youtube-dl, you get an error as this :

[youtube] Setting language
[youtube] pgEFfZOV9GQ: Downloading video webpage
[youtube] pgEFfZOV9GQ: Downloading video info webpage
[youtube] pgEFfZOV9GQ: Extracting video information
[youtube] pgEFfZOV9GQ: Encrypted signatures detected.

ERROR: unable to download video

then you try to solve by this command : 

sudo youtube-dl -U

you just get this message : 

It looks like you installed youtube-dl with a package manager, pip, setup.py or a tarball. Please use that to update.

well, the solution is :

sudo pip install --upgrade youtube-dl

Downloading/unpacking youtube-dl from https://pypi.python.org/packages/source/y/youtube_dl/youtube_dl-2014.02.26.tar.gz#md5=941720c118544cb0d00dde072b8667f7

  Downloading youtube_dl-2014.02.26.tar.gz (311kB): 311kB downloaded

  Running setup.py egg_info for package youtube-dl

    

Installing collected packages: youtube-dl

  Found existing installation: youtube-dl 2013.08.29

    Uninstalling youtube-dl:

      Successfully uninstalled youtube-dl

  Running setup.py install for youtube-dl

    

    Installing youtube-dl script to /usr/local/bin

Successfully installed youtube-dl

Cleaning up...

then everything will run properly.