re-size mp4,3gp,rm,3g2,mpg,wmv video file using c#

Question

Hi all,
I need to re-size mp4,3gp,rm,3g2,mpg,wmv video file in my given size.
Let a mother mp4 or 3gp video file file have 300x400 pixel.I want to re-size it 100x120,240x300,120x320 size.How can i re-size the video file in my given size USING C#.Pls help or guide me to do it.
Thanks in advance.
Riad