Visual-studio – create virtual webcam application which takes images as input and send it to any video chat application

It is possible through a virtual device, see

• Virtual webcam input as byte stream
• Is it possible to fake a video stream as virtual cam that is visible in Skype, Lync etc?

You will have hard time implementing this in C# only, as the APIs are for native code.

I use AForge.Video (find it here: code.google.com/p/aforge/) because it's a very fast c# implementation. i am very pleased with the performance and it effortlessly captures from two HD webcams at 30fps on an 8 year old PC. the data is supplied as a native IntPtr so it's ideal for further processing using native code or opencv.

opencv wrappers emgu and opencvsharp both implement a rudimentary video capture functionality which might be sufficient for your purposes. clearly if you are going perform image processing / computer vision you might want to use those anyway.