C#，每 5 秒从网络摄像头连续保存帧

Question

当运行基于 GUI 的代码实际上打开网络摄像头提要并每 5 秒保存一次帧时，在运行dom 运行时间（可能是 5 分钟）之后或 20 分钟）发生异常“'Object in use by another process'”，可能与当前帧的保存有关。任何想法导致问题的原因以及应该进行哪些代码修改？

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

如果您从不同的线程访问对象，您需要一个锁。
当您从不同线程访问控件时也使用调用。

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();
}

也如@TheGeneral所说，保存后处理pictureBox2.Image。

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