I need to capture video from a webcam. Are there any classes in C#/.NET that can help me with this. I am only interested in real time data.
And are there any good C#/.NET books that I can study to gain deep knowledge on the language and the platform?
This is what I use. You need a first class to iterate your devices:
public class DeviceManager
{
[DllImport("avicap32.dll")]
protected static extern bool capGetDriverDescriptionA(short wDriverIndex,
[MarshalAs(UnmanagedType.VBByRefStr)]ref String lpszName,
int cbName, [MarshalAs(UnmanagedType.VBByRefStr)] ref String lpszVer, int cbVer);
static ArrayList devices = new ArrayList();
public static TCamDevice[] GetAllDevices()
{
String dName = "".PadRight(100);
String dVersion = "".PadRight(100);
for (short i = 0; i < 10; i++)
{
if (capGetDriverDescriptionA(i, ref dName, 100, ref dVersion, 100))
{
TCamDevice d = new TCamDevice(i);
d.Name = dName.Trim();
d.Version = dVersion.Trim();
devices.Add(d);
}
}
return (TCamDevice[])devices.ToArray(typeof(TCamDevice));
}
public static TCamDevice GetDevice(int deviceIndex)
{
return (TCamDevice)devices[deviceIndex];
}
}
ANd this one to control the cam.
public class TCamDevice
{
private const short WM_CAP = 0x400;
private const int WM_CAP_DRIVER_CONNECT = 0x40a;
private const int WM_CAP_DRIVER_DISCONNECT = 0x40b;
private const int WM_CAP_EDIT_COPY = 0x41e;
private const int WM_CAP_SET_PREVIEW = 0x432;
private const int WM_CAP_SET_OVERLAY = 0x433;
private const int WM_CAP_SET_PREVIEWRATE = 0x434;
private const int WM_CAP_SET_SCALE = 0x435;
private const int WS_CHILD = 0x40000000;
private const int WS_VISIBLE = 0x10000000;
[DllImport("avicap32.dll")]
protected static extern int capCreateCaptureWindowA([MarshalAs(UnmanagedType.VBByRefStr)] ref string lpszWindowName,
int dwStyle, int x, int y, int nWidth, int nHeight, int hWndParent, int nID);
[DllImport("user32", EntryPoint = "SendMessageA")]
protected static extern int SendMessage(int hwnd, int wMsg, int wParam, [MarshalAs(UnmanagedType.AsAny)] object lParam);
[DllImport("user32")]
protected static extern int SetWindowPos(int hwnd, int hWndInsertAfter, int x, int y, int cx, int cy, int wFlags);
[DllImport("user32")]
protected static extern bool DestroyWindow(int hwnd);
int index;
int deviceHandle;
public TCamDevice(int index)
{
this.index = index;
}
private string _name;
public string Name
{
get { return _name; }
set { _name = value; }
}
private string _version;
public string Version
{
get { return _version; }
set { _version = value; }
}
public override string ToString()
{
return this.Name;
}
/// <summary>
/// To Initialize the device
/// </summary>
/// <param name="windowHeight">Height of the Window</param>
/// <param name="windowWidth">Width of the Window</param>
/// <param name="handle">The Control Handle to attach the device</param>
public void Init(int windowHeight, int windowWidth, int handle)
{
string deviceIndex = Convert.ToString(this.index);
deviceHandle = capCreateCaptureWindowA(ref deviceIndex, WS_VISIBLE | WS_CHILD, 0, 0, windowWidth, windowHeight, handle, 0);
if (SendMessage(deviceHandle, WM_CAP_DRIVER_CONNECT, this.index, 0) > 0)
{
SendMessage(deviceHandle, WM_CAP_SET_SCALE, -1, 0);
SendMessage(deviceHandle, WM_CAP_SET_PREVIEWRATE, 0x42, 0);
SendMessage(deviceHandle, WM_CAP_SET_PREVIEW, -1, 0);
SetWindowPos(deviceHandle, 1, 0, 0, windowWidth, windowHeight, 6);
}
}
/// <summary>
/// Shows the webcam preview in the control
/// </summary>
/// <param name="windowsControl">Control to attach the webcam preview</param>
public void ShowWindow(global::System.Windows.Forms.Control windowsControl)
{
Init(windowsControl.Height, windowsControl.Width, windowsControl.Handle.ToInt32());
}
/// <summary>
/// Stop the webcam and destroy the handle
/// </summary>
public void Stop()
{
SendMessage(deviceHandle, WM_CAP_DRIVER_DISCONNECT, this.index, 0);
DestroyWindow(deviceHandle);
}
}
The ShowWindow takes your PictureBox as parameter.
I would recommend you to use 3rd party library. It would be the best solution instead of inventing your own bicycle. Here, I used AForge.Net. Though it has some problems concerning performance, but I tweaked the library myself when performance became a critical issue for me. The AForge.Net code is open source and you can tweak it to your needs.
As for books you definitely should look at Jeffrey Richter's "CLR via C#" and John Skeet's "C# in Depth".
You can use Microsoft Expression Encoder 4 SP2. This is a great library that you can add to your project and get live preview, snapshots, and video recording. More details are included a sample project by Massimo Conti: How to use a web cam in C# with .NET Framework 4.0 and Microsoft Expression Encoder 4
Use WebCam_Capture.dll for capturing Photos and videos. Here is Link here is source code for that LINK
