C#, Saving frames from webcam continuously every 5s

Question

When ran the code which is GUI based and it actually opens a webcamera feed and saves frame every 5s, after a random running time(it could be 5 min or 20 min) there is an exception occuring ''Object in use by another process'' possibly related to the saving of the current frame. Any ideas what causes the problem and what code modifications should be done?

public partial class Form1 : Form
    {
        private FilterInfoCollection CaptureDevices;
        private VideoCaptureDevice videoSource;
        bool blncapturing;

        public Form1()
        {
            InitializeComponent();
            timer1.Enabled = false;
            timer1.Interval = 5000;
            blncapturing = false;
        }



        private void button1_Click(object sender, EventArgs e)
        {
            videoSource = new VideoCaptureDevice(CaptureDevices[comboBox1.SelectedIndex].MonikerString);
            videoSource.NewFrame += new NewFrameEventHandler(VideoSource_NewFrame);
            videoSource.Start();
            timer1.Enabled = true;
        }


        private void VideoSource_NewFrame(object sender, NewFrameEventArgs eventArgs)
        {
            if (pictureBox1.Image != null)
                ((IDisposable)pictureBox1.Image).Dispose();


            pictureBox1.Image = (Bitmap)eventArgs.Frame.Clone();
        }

        private void Form1_Load_1(object sender, EventArgs e)
        {

            CaptureDevices = new FilterInfoCollection(FilterCategory.VideoInputDevice);
            foreach (FilterInfo Device in CaptureDevices)
            {
                comboBox1.Items.Add(Device.Name);
            }
            comboBox1.SelectedIndex = 0;
            videoSource = new VideoCaptureDevice();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            videoSource.Stop();
            pictureBox1.Image = null;
            pictureBox1.Invalidate();
            pictureBox2.Image = null;
            pictureBox2.Invalidate();

        }

        private void button3_Click(object sender, EventArgs e)
        {
            Capturing();
        }

        private void button4_Click(object sender, EventArgs e)
        {
            if (videoSource.IsRunning == true)
            {
                videoSource.Stop();
            }
            Application.Exit(null);
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            timer1.Stop();
            Capturing();
            timer1.Start();
        }

        private void Capturing()
        {
            try
            {
                if (blncapturing == false)
                {
                    blncapturing = true;

                    pictureBox2.Image = (Bitmap)pictureBox1.Image.Clone();

                    string strGrabFileName = String.Format("C:\\Users\\echristo\\Desktop\\trial\\Snapshot_{0:yyyyMMdd_hhmmss.fff}.bmp", DateTime.Now);
                    pictureBox2.Image.Save(strGrabFileName, System.Drawing.Imaging.ImageFormat.Jpeg) ;
                    blncapturing = false;

                }
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);                
            }


        }

Answer 1

If you access objects from different threads you need a lock.
Also use invoke when you access a control from a different thread.

private readonly object myLock = new object();

private void VideoSource_NewFrame(object sender, NewFrameEventArgs eventArgs)
{
    lock (myLock) {
        this.Invoke((Action)(() => {
            if (pictureBox1.Image != null)
                ((IDisposable)pictureBox1.Image).Dispose();


            pictureBox1.Image = (Bitmap)eventArgs.Frame.Clone();        

        }));
    }
}

private void timer1_Tick(object sender, EventArgs e)
{
    timer1.Stop();

    // you can try with timer1 inside the lock
    lock (myLock) {
        // you don't need invoke here, because the winforms timer runs on the main thread.
        Capturing();    
    }

    timer1.Start();
}

Also as @TheGeneral said, dispose pictureBox2.Image after saving.