morean51 wrote:

then what is the direct way to download youtube video thank you in advance

First install the script youtube-dl mentioned earlier in the thread; on Ubuntu the command is

sudo apt-get install youtube-dl

You can then use youtube-dl to download the clip associated with a given youtube URL, e.g.:

youtube-dl "http://www.youtube.com/watch?v=a9xAKttWgP4"

The output file is a flash video, and should be playable with e.g. mplayer and vlc, or you can convert it to other formats using ffmpeg or mencoder.