Ios 单击开始录制时，如何以相同的时间间隔开始视频录制？

我已经用avcapturesession实现了视频和音频录制。开始录音需要一些时间，通常需要1到2秒

如果需要更多信息，请随意评论。 设置捕获会话执行以下步骤：

• 添加捕获会话
• 添加视频输入
• 添加音频输入
• 添加视频预览层
• 添加电影输出
• 为输出连接设置摄像头配置
• 启动捕获会话
  -（无效）设置捕获会话{

   // Set up capture session
       captureSession = [AVCaptureSession new];
  
  //add video intput
  AVCaptureDevice *videoCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
  
     if (videoCaptureDevice) {
      NSError *error;
  
      videoInputDevice =  [AVCaptureDeviceInput deviceInputWithDevice:videoCaptureDevice error:&error];
      if(!error){
          if ([captureSession canAddInput:videoInputDevice]) {
              [captureSession addInput:videoInputDevice];
          }else{
              NSLog(@"Failed to add video input");
          }
      }else{
          NSLog(@"Failed to create video device");
      }
  }else{
      NSLog(@"Failed to create video capture device");
  }
  
  // add audio input
  AVCaptureDevice *audioCaptureDevie = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
  
  NSError *error = nil;
  
  AVCaptureDeviceInput *audioInputDevice = [AVCaptureDeviceInput deviceInputWithDevice:audioCaptureDevie error:&error];
  if (audioInputDevice) {
      [captureSession addInput:audioInputDevice];
  }
  
  // add outputs
  
  // add video preview layer
  NSLog(@"Adding video preview layer");
  
  [self setPreviewLayer:[[AVCaptureVideoPreviewLayer alloc] initWithSession:captureSession]];
  
  [[self previewLayer] setVideoGravity:AVLayerVideoGravityResizeAspectFill];
  
  //add movie ouput
  movieFileOutput = [[AVCaptureMovieFileOutput alloc] init];
  movieFileOutput.minFreeDiskSpaceLimit = 1024 * 1024;
  
  if ([captureSession canAddOutput:movieFileOutput])
      [captureSession addOutput:movieFileOutput];
  
  // set up camera configuration for output connection
  [self setUpCameraConfiguration];
  
  [captureSession setSessionPreset:AVCaptureSessionPresetMedium];
  if ([captureSession canSetSessionPreset:AVCaptureSessionPreset640x480])
      [captureSession setSessionPreset:AVCaptureSessionPreset640x480];
  
  
  
  //----- DISPLAY THE PREVIEW LAYER -----
  //Display it full screen under out view controller existing controls
  NSLog(@"Display the preview layer");
  CGRect layerRect = [[[self view] layer] bounds];
  [_previewLayer setBounds:layerRect];
  [_previewLayer setPosition:CGPointMake(CGRectGetMidX(layerRect),
                                         CGRectGetMidY(layerRect))];
  //[[[self view] layer] addSublayer:[[self CaptureManager] previewLayer]];
  //We use this instead so it goes on a layer behind our UI controls (avoids us having to manually bring each control to the front):
  UIView *cameraView = [[UIView alloc] init];
  [[self view] addSubview:cameraView];
  [self.view sendSubviewToBack:cameraView];
  
  [[cameraView layer] addSublayer:_previewLayer];
  
  
  //----- START THE CAPTURE SESSION RUNNING -----
  [captureSession startRunning];
  

  }

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1。添加会话配置代码。2.添加开始录制的代码。3.您是否创建了一个单独的DispatchGroup来处理AVCaptureSession？我想说，这可能与不在后台做事情有关，但我们首先需要更多信息。你能分享代码吗？请参考此链接，它可能会对你有所帮助。