How to code a screen recording software?

Question

hello,
I would like to assing myself a new project to deal with as a hobby
I just want to code a software in c#, that records the screen activities as avi, or mpeg format.
I want to use it for training, or educational purposes so that it could be more helpful than reading hands on labs.
I would be happy, if you can point me where to start!
thanks

bilnaad · Answer

I believe the first thing to do is looking for some graphic api's like openGL or DirectX wich are speedy enough to capture something and work with large images.