We can not fetch videos from this type of page.
Your URL was: http://save-video.mp4?http%3A%2F%2Fv17.lscache6.googlevideo.com%2Fvideoplayback%3Fid%3D6ae1831e2449eb55%26itag%3D18%26sparams%3Did%252Cexpire%252Cip%252Cipbits%252Citag%26ip%3D174.36.175.210%26signature%3D44940DCBCB3FB589674E6E1BCDC645F78D941B01.2EC84ABBED8226E293E37278ACEDE05E8031F3D5%26sver%3D3%26expire%3D1239986016%26key%3Dyt1%26ipbits%3D0
The URL must be like http://www.youtube.com/watch?v=KPtX7hak0Qs
https://www.
and replace with pwn
Example: