1

在 form1 顶部我做了：

private volatile bool _workersEnabled;
private ConcurrentQueue<Bitmap> _imageBuffer;
Thread threadA;
Thread threadB;

然后在构造函数中：

_workersEnabled = false;
_imageBuffer = new ConcurrentQueue<Bitmap>();

threadA = new Thread(CaptureScreensEntryPoint);
threadB = new Thread(ConsumeScreensEntryPoint);

然后在按钮单击事件中：

private void StartRecording_Click(object sender, EventArgs e)
{
    ffmp.Start("test.avi", 25);
    _workersEnabled = true;
    threadA.Start();
    threadA.Start();

    //Disable the button, so we eliminate the possibility to start this twice (would throw an exception anyway).
    StartRecording.Enabled = false;
}

然后在它之后我添加：

private void CaptureScreensEntryPoint()
{
    while(_workersEnabled)
    {
        Bitmap bitmap = (Bitmap)ScreenCapture.CaptureScreen(true);

        //Just add it to the queue.
        _imageBuffer.Enqueue(bitmap);

        //Wait a bit
        Thread.Sleep(40);
    }
}

private void ConsumeScreensEntryPoint()
{
    while (_workersEnabled)
    {
        Bitmap workItem = null;
        if (_imageBuffer.TryDequeue(out workItem))
        {
            ffmp.PushFrame(workItem);
            workItem.Dispose();
        }

        //Also wait a bit here. Don't want to eat up the entire processor.
        Thread.Sleep(10);
    }
}

例外是threadA.Start();：

ThreadStateException ：线程正在运行或终止；它无法重新启动

System.Threading.ThreadStateException was unhandled
  HResult=-2146233056
  Message=Thread is running or terminated; it cannot restart.
  Source=mscorlib
  StackTrace:
       at System.Threading.Thread.StartupSetApartmentStateInternal()
       at System.Threading.Thread.Start(StackCrawlMark& stackMark)
       at System.Threading.Thread.Start()
       at ScreenVideoRecorder.Form1.StartRecording_Click(Object sender, EventArgs e) in d:\C-Sharp\ScreenVideoRecorder\ScreenVideoRecorderWorkingVersion\Form1.cs:line 152
       at System.Windows.Forms.Control.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnClick(EventArgs e)
       at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
       at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
       at System.Windows.Forms.Control.WndProc(Message& m)
       at System.Windows.Forms.ButtonBase.WndProc(Message& m)
       at System.Windows.Forms.Button.WndProc(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
       at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       at System.Windows.Forms.Application.Run(Form mainForm)
       at ScreenVideoRecorder.Program.Main() in d:\C-Sharp\ScreenVideoRecorder\ScreenVideoRecorderWorkingVersion\Program.cs:line 18
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException:

我该如何解决？

4

2 回答 2

1

我不确定哪一个需要更长的时间：ScreenCapture.CaptureScreen或ffmp.PushFrame(bitmap). 由于它是位图，我假设 ffmp 不能那么快并且它会占用一些时间。

我会采用生产者/消费者的方法。您有线程 A 执行屏幕截图，将它们推送到 aConcurrentQueue并从那里被线程 B 拾取，并将它们推送到 ffmp。

一些示例代码（未经测试，也不能保证完全正常工作，因此您可能需要进行一些调整）：

//We need this thread for cross-thread access, so we don't want it cached. 
private volatile bool _workersEnabled;
private ConcurrentQueue<Bitmap> _imageBuffer;

public Form1()
{
  InitializeComponent();
  ffmp = new Ffmpeg();
  sc = new ScreenCapture();

  _workersEnabled = false; 
  _imageBuffer = new ConcurrentQueue<Bitmpap>();

  threadA = new Thread(CaptureScreensEntryPoint);
  threadB = new Thread(ConsumeScreensEntryPoint);
}

private void StartRecording_Click(object sender, EventArgs e)
{
  _workersEnabled = true; 
  threadA.Start();
  threadB.Start();

  //Disable the button, so we eliminate the possibility to start this twice (would throw an exception anyway).
  StartRecording.Enabled = false;
}

private void CaptureScreensEntryPoint() 
{
  while(_workersEnabled)
  {
    Bitmap bitmap = (Bitmap)ScreenCapture.CaptureScreen(true);

    //just add it to the queue.
    _imageBuffer.Enqueue(bitmap);

    //wait a bit
    Thread.Sleep(40);
  }
}

private void ConsumeScreensEntryPoint() 
{
  while(_workersEnabled)
  {
    Bitmap workItem = null;
    if(_imageBuffer.TryDequeue(out workItem))
    { 
      ffmp.PushFrame(workItem);
      workItem.Dispose();
    }

    //Also wait a bit here. Don't want to eat up the entire processor.
    Thread.Sleep(10);
  }
}

确保设置_workersEnabled为false您想要停止工作人员的时间，例如当表单关闭时，或者您可能有一个专用按钮。您可能还想添加一些错误处理并为两个线程配置睡眠周期。

笔记

我想我可以用 TPL 完成它，但这有点快发布。随意调整解决方案或发布新的解决方案。

于 2013-05-30T21:12:29.537 回答
0

尝试将捕获代码放在单独的线程中。我为桌面捕获应用程序做了类似的事情，并且能够获得大约 60 FPS。

于 2013-05-30T20:29:16.203 回答