capturing video with a webcam

[rajibnsu]

While searching for capturing video with a webcam I god the following code.It gives two errors.Says:The type or namespace name 'WebcamEventArgs' does not exit in the namespace 'WebCam_Capture' (are you missing an assembly reference?)

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace WebCam_Capture
{
    /// <summary>
    /// Summary description for UserControl1.
    /// </summary>
    [System.Drawing.ToolboxBitmap(typeof(WebCamCapture), "CAMERA.ICO")] // 
    [Designer("Sytem.Windows.Forms.Design.ParentControlDesigner,System.Design", typeof(System.ComponentModel.Design.IDesigner))] // 
    public class WebCamCapture : System.Windows.Forms.UserControl
    {
        private System.ComponentModel.IContainer components;
        private System.Windows.Forms.Timer timer1;
        // 
        private int m_TimeToCapture_milliseconds = 100;
        private int m_Width = 320;
        private int m_Height = 240;
        private int mCapHwnd;
        private ulong m_FrameNumber = 0;
        // 
        private WebCam_Capture.WebcamEventArgs x = new WebCam_Capture.WebcamEventArgs();
        private IDataObject tempObj;
        private System.Drawing.Image tempImg;
        private bool bStopped = true;
        // 
        public delegate void WebCamEventHandler(object source, WebCam_Capture.WebcamEventArgs e);
        // 
        public event WebCamEventHandler ImageCaptured;
        #region API Declarations
        [DllImport("user32", EntryPoint = "SendMessage")]
        public static extern int SendMessage(int hWnd, uint Msg, int wParam, int lParam);
        [DllImport("avicap32.dll", EntryPoint = "capCreateCaptureWindowA")]
        public static extern int capCreateCaptureWindowA(string lpszWindowName, int dwStyle, int X, int Y, int nWidth, int nHeight, int hwndParent, int nID);
        [DllImport("user32", EntryPoint = "OpenClipboard")]
        public static extern int OpenClipboard(int hWnd);
        [DllImport("user32", EntryPoint = "EmptyClipboard")]
        public static extern int EmptyClipboard();
        [DllImport("user32", EntryPoint = "CloseClipboard")]
        public static extern int CloseClipboard();
        #endregion
        #region API Constants
        public const int WM_USER = 1024;
        public const int WM_CAP_CONNECT = 1034;
        public const int WM_CAP_DISCONNECT = 1035;
        public const int WM_CAP_GET_FRAME = 1084;
        public const int WM_CAP_COPY = 1054;
        public const int WM_CAP_START = WM_USER;
        public const int WM_CAP_DLG_VIDEOFORMAT = WM_CAP_START + 41;
        public const int WM_CAP_DLG_VIDEOSOURCE = WM_CAP_START + 42;
        public const int WM_CAP_DLG_VIDEODISPLAY = WM_CAP_START + 43;
        public const int WM_CAP_GET_VIDEOFORMAT = WM_CAP_START + 44;
        public const int WM_CAP_SET_VIDEOFORMAT = WM_CAP_START + 45;
        public const int WM_CAP_DLG_VIDEOCOMPRESSION = WM_CAP_START + 46;
        public const int WM_CAP_SET_PREVIEW = WM_CAP_START + 50;
        #endregion
        #region NOTES
 
        #endregion
 
        public WebCamCapture()
        {
                    InitializeComponent();
        }
        /// <summary>
        /// Override the class's finalize method, so we can stop
        /// the video capture on exit
        /// </summary>
        ~WebCamCapture()
        {
            this.Stop();
        }
                protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
                if (components != null)
                    components.Dispose();
            }
            base.Dispose(disposing);
        }
        #region Component Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify 
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.components = new System.ComponentModel.Container();
            this.timer1 = new System.Windows.Forms.Timer(this.components);
            this.timer1.Tick += new System.EventHandler(this.timer1_Tick);
            this.Name = "WebCamCapture";
            this.Size = new System.Drawing.Size(342, 252);
            this.Load += new System.EventHandler(this.WebCamCapture_Load);
        }
        #endregion
        #region Control Properties
        public int TimeToCapture_milliseconds
        {
            get
            { return m_TimeToCapture_milliseconds; }
            set
            { m_TimeToCapture_milliseconds = value; }
        }
        /// <summary>
        /// The height of the video capture image
        /// </summary>
        public int CaptureHeight
        {
            get
            { return m_Height; }
 
            set
            { m_Height = value; }
        }
        /// <summary>
        /// </summary>
        public int CaptureWidth
        {
            get
            { return m_Width; }
            set
            { m_Width = value; }
        }
        /// <summary>
        /// </summary>
        public ulong FrameNumber
        {
            get
            { return m_FrameNumber; }
            set
            { m_FrameNumber = value; }
        }
        #endregion
        #region Start and Stop Capture Functions
        /// <summary>
        /// </summary>
        /// <param name="FrameNumber">the frame number to start at. 
        /// Set to 0 to let the control allocate the frame number</param>
        public void Start(ulong FrameNum)
        {
            try
            {
                this.Stop();
                mCapHwnd = capCreateCaptureWindowA("WebCap", 0, 0, 0, m_Width, m_Height, this.Handle.ToInt32(), 0);
                Application.DoEvents();
                SendMessage(mCapHwnd, WM_CAP_CONNECT, 0, 0);
                SendMessage(mCapHwnd, WM_CAP_SET_PREVIEW, 0, 0);
                m_FrameNumber = FrameNum;
                this.timer1.Interval = m_TimeToCapture_milliseconds;
                bStopped = false;
                this.timer1.Start();
            }
            catch (Exception excep)
            {
                MessageBox.Show("An error ocurred while starting the video capture. Check that your webcamera is connected properly and turned on.\r\n\n" + excep.Message);
                this.Stop();
            }
        }
        /// <summary>
        /// Stops the video capture
        /// </summary>
        public void Stop()
        {
            try
            {
                bStopped = true;
                this.timer1.Stop();
                Application.DoEvents();
                SendMessage(mCapHwnd, WM_CAP_DISCONNECT, 0, 0);
            }
            catch (Exception excep)
            {             }
        }
        #endregion
        #region Video Capture Code
        /// <summary>
        /// Capture the next frame from the video feed
        /// </summary>
        private void timer1_Tick(object sender, System.EventArgs e)
        {
            try
            {
                              this.timer1.Stop();
                              SendMessage(mCapHwnd, WM_CAP_GET_FRAME, 0, 0);
                              SendMessage(mCapHwnd, WM_CAP_COPY, 0, 0);
                              if (ImageCaptured != null)
                {
                                  tempObj = Clipboard.GetDataObject();
                    tempImg = (System.Drawing.Bitmap)tempObj.GetData(System.Windows.Forms.DataFormats.Bitmap);
 
                    x.WebCamImage = tempImg.GetThumbnailImage(m_Width, m_Height, null, System.IntPtr.Zero);
                                  this.ImageCaptured(this, x);
                }
                              Application.DoEvents();
                if (!bStopped)
                    this.timer1.Start();
            }
            catch (Exception excep)
            {
                MessageBox.Show("An error ocurred while capturing the video image. The video capture will now be terminated.\r\n\n" + excep.Message);
                this.Stop();             }
        }
        #endregion
        private void WebCamCapture_Load(object sender, System.EventArgs e)
        {
 
        }
    }
}

Can anybody help me?

[brien86]

I had the same problem. I changed the code, this works for me...

using System;
using System.Collections;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Windows.Forms;
using System.Runtime.InteropServices;
 
namespace WebcamWhiteboard
{
    /// <summary>
    /// Summary description for UserControl1.
    /// </summary>
    [System.Drawing.ToolboxBitmap(typeof(WebCamCapture), "CAMERA.ICO")] // toolbox bitmap
    [Designer("Sytem.Windows.Forms.Design.ParentControlDesigner,System.Design", typeof(System.ComponentModel.Design.IDesigner))] // make composite
    public class WebCamCapture : System.Windows.Forms.UserControl
    {
        private System.ComponentModel.IContainer components;
        private System.Windows.Forms.Timer timer1;
 
        // property variables
        private int m_TimeToCapture_milliseconds = 100;
        private int m_Width = 320;
        private int m_Height = 240;
        private int mCapHwnd;
        private ulong m_FrameNumber = 0;
 
        /// <summary>
        /// This was missing.
        /// </summary>
        private class WebcamEventArgs
        {
            public Image WebCamImage;
        }
 
        // global variables to make the video capture go faster
        private WebCamCapture.WebcamEventArgs x = new WebCamCapture.WebcamEventArgs();
        private IDataObject tempObj;
        private System.Drawing.Image tempImg;
        private bool bStopped = true;
 
        // event delegate
        public delegate void WebCamEventHandler(object source, WebCamCapture.WebcamEventArgs e);
        // fired when a new image is captured
        public event WebCamEventHandler ImageCaptured;
 
        #region API Declarations
 
        [DllImport("user32", EntryPoint = "SendMessage")]
        public static extern int SendMessage(int hWnd, uint Msg, int wParam, int lParam);
 
        [DllImport("avicap32.dll", EntryPoint = "capCreateCaptureWindowA")]
        public static extern int capCreateCaptureWindowA(string lpszWindowName, int dwStyle, int X, int Y, int nWidth, int nHeight, int hwndParent, int nID);
 
        [DllImport("user32", EntryPoint = "OpenClipboard")]
        public static extern int OpenClipboard(int hWnd);
 
        [DllImport("user32", EntryPoint = "EmptyClipboard")]
        public static extern int EmptyClipboard();
 
        [DllImport("user32", EntryPoint = "CloseClipboard")]
        public static extern int CloseClipboard();
 
        #endregion
 
        #region API Constants
 
        public const int WM_USER = 1024;
 
        public const int WM_CAP_CONNECT = 1034;
        public const int WM_CAP_DISCONNECT = 1035;
        public const int WM_CAP_GET_FRAME = 1084;
        public const int WM_CAP_COPY = 1054;
 
        public const int WM_CAP_START = WM_USER;
 
        public const int WM_CAP_DLG_VIDEOFORMAT = WM_CAP_START + 41;
        public const int WM_CAP_DLG_VIDEOSOURCE = WM_CAP_START + 42;
        public const int WM_CAP_DLG_VIDEODISPLAY = WM_CAP_START + 43;
        public const int WM_CAP_GET_VIDEOFORMAT = WM_CAP_START + 44;
        public const int WM_CAP_SET_VIDEOFORMAT = WM_CAP_START + 45;
        public const int WM_CAP_DLG_VIDEOCOMPRESSION = WM_CAP_START + 46;
        public const int WM_CAP_SET_PREVIEW = WM_CAP_START + 50;
 
        #endregion
 
        #region NOTES
 
        /*
   * If you want to allow the user to change the display size and 
   * color format of the video capture, call:
   * SendMessage (mCapHwnd, WM_CAP_DLG_VIDEOFORMAT, 0, 0);
   * You will need to requery the capture device to get the new settings
  */
 
        #endregion
 
 
        public WebCamCapture()
        {
            // This call is required by the Windows.Forms Form Designer.
            InitializeComponent();
        }
 
        /// <summary>
        /// Override the class's finalize method, so we can stop
        /// the video capture on exit
        /// </summary>
        ~WebCamCapture()
        {
            this.Stop();
        }
 
        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        protected override void Dispose(bool disposing)
        {
            if (disposing)
            {
 
                if (components != null)
                    components.Dispose();
            }
            base.Dispose(disposing);
        }
 
        #region Component Designer generated code
        /// <summary>
        /// Required method for Designer support - do not modify 
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            this.components = new System.ComponentModel.Container();
            this.timer1 = new System.Windows.Forms.Timer(this.components);
            // 
            // timer1
            // 
            this.timer1.Tick += new System.EventHandler(this.timer1_Tick);
            // 
            // WebCamCapture
            // 
            this.Name = "WebCamCapture";
            this.Size = new System.Drawing.Size(342, 252);
            this.Load += new System.EventHandler(this.WebCamCapture_Load);
 
        }
        #endregion
 
        #region Control Properties
 
        /// <summary>
        /// The time intervale between frame captures
        /// </summary>
        public int TimeToCapture_milliseconds
        {
            get
            { return m_TimeToCapture_milliseconds; }
 
            set
            { m_TimeToCapture_milliseconds = value; }
        }
 
        /// <summary>
        /// The height of the video capture image
        /// </summary>
        public int CaptureHeight
        {
            get
            { return m_Height; }
 
            set
            { m_Height = value; }
        }
 
        /// <summary>
        /// The width of the video capture image
        /// </summary>
        public int CaptureWidth
        {
            get
            { return m_Width; }
 
            set
            { m_Width = value; }
        }
 
        /// <summary>
        /// The sequence number to start at for the frame number. OPTIONAL
        /// </summary>
        public ulong FrameNumber
        {
            get
            { return m_FrameNumber; }
 
            set
            { m_FrameNumber = value; }
        }
 
        #endregion
 
        #region Start and Stop Capture Functions
 
        /// <summary>
        /// Starts the video capture
        /// </summary>
        /// <param name="FrameNumber">the frame number to start at. 
        /// Set to 0 to let the control allocate the frame number</param>
        public void Start(ulong FrameNum)
        {
            try
            {
                // for safety, call stop, just in case we are already running
                this.Stop();
 
                // setup a capture window
                mCapHwnd = capCreateCaptureWindowA("WebCap", 0, 0, 0, m_Width, m_Height, this.Handle.ToInt32(), 0);
 
                // connect to the capture device
                Application.DoEvents();
                SendMessage(mCapHwnd, WM_CAP_CONNECT, 0, 0);
                SendMessage(mCapHwnd, WM_CAP_SET_PREVIEW, 0, 0);
 
                // set the frame number
                m_FrameNumber = FrameNum;
 
                // set the timer information
                this.timer1.Interval = m_TimeToCapture_milliseconds;
                bStopped = false;
                this.timer1.Start();
            }
 
            catch (Exception excep)
            {
                MessageBox.Show("An error ocurred while starting the video capture. Check that your webcamera is connected properly and turned on.\r\n\n" + excep.Message);
                this.Stop();
            }
        }
 
        /// <summary>
        /// Stops the video capture
        /// </summary>
        public void Stop()
        {
            try
            {
                // stop the timer
                bStopped = true;
                this.timer1.Stop();
 
                // disconnect from the video source
                Application.DoEvents();
                SendMessage(mCapHwnd, WM_CAP_DISCONNECT, 0, 0);
            }
 
            catch (Exception excep)
            { // don't raise an error here.
            }
 
        }
 
        #endregion
 
        #region Video Capture Code
 
        /// <summary>
        /// Capture the next frame from the video feed
        /// </summary>
        private void timer1_Tick(object sender, System.EventArgs e)
        {
            try
            {
                // pause the timer
                this.timer1.Stop();
 
                // get the next frame;
                SendMessage(mCapHwnd, WM_CAP_GET_FRAME, 0, 0);
 
                // copy the frame to the clipboard
                SendMessage(mCapHwnd, WM_CAP_COPY, 0, 0);
 
                // paste the frame into the event args image
                if (ImageCaptured != null)
                {
                    // get from the clipboard
                    tempObj = Clipboard.GetDataObject();
                    tempImg = (System.Drawing.Bitmap)tempObj.GetData(System.Windows.Forms.DataFormats.Bitmap);
 
                    /*
                    * For some reason, the API is not resizing the video
                    * feed to the width and height provided when the video
                    * feed was started, so we must resize the image here
                    */
                    x.WebCamImage = tempImg.GetThumbnailImage(m_Width, m_Height, null, System.IntPtr.Zero);
 
                    // raise the event
                    this.ImageCaptured(this, x);
                }
 
                // restart the timer
                Application.DoEvents();
                if (!bStopped)
                    this.timer1.Start();
            }
 
            catch (Exception excep)
            {
                MessageBox.Show("An error ocurred while capturing the video image. The video capture will now be terminated.\r\n\n" + excep.Message);
                this.Stop(); // stop the process
            }
        }
 
        #endregion
 
        private void WebCamCapture_Load(object sender, System.EventArgs e)
        {
 
        }
    }
}

While searching for capturing video with a webcam I god the following code.It gives two errors.Says:The type or namespace name 'WebcamEventArgs' does not exit in the namespace 'WebCam_Capture' (are you missing an assembly reference?)
Can anybody help me?

[Plater]

Very interesting, does this only work for a particular cam type or for all of them that windows recognizes?

[parshupooja]

it looks very nice, If you guys can post detail info or article for that, will be great