Question

What is The Easiest, fastest Way to capture video stream from camera with C#?

Answer 1

Simpliest and easiest probably would be using Microsoft Expression Encoder SDK:

static void Main( string[] args )
{
    var job = new Microsoft.Expression.Encoder.Live.LiveJob();
    job.AddDeviceSource( job.VideoDevices[0],job.AudioDevices[0] );
    var w = new System.Windows.Forms.Form();
    w.Show();
    var source = job.DeviceSources[0];
    source.PreviewWindow = new Microsoft.Expression.Encoder.Live.PreviewWindow( new System.Runtime.InteropServices.HandleRef(w, w.Handle) );
    Console.ReadKey();
}