攝像頭的視頻幀在iOS中使用AVFoundation框架？

Question

我從來沒有與AVFoundation框架合作過，我想從後置攝像頭獲取視頻幀並使用這些幀進行處理。任何人都可以幫助我，您的經驗將不勝感激。由於

Answer 1

您可以使用下面的代碼與AVFoundation啓動相機會以拍攝靜止圖像：

AVCaptureSession *session; 
AVCaptureStillImageOutput *stillImageOutput; 

session = [[AVCaptureSession alloc] init]; 
[session setSessionPreset:AVCaptureSessionPresetPhoto]; 

AVCaptureDevice *inputDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo]; 
NSError *error; 
AVCaptureDeviceInput *deviceInput = [AVCaptureDeviceInput deviceInputWithDevice:inputDevice error:&error]; 

if ([session canAddInput:deviceInput]) { 
    [session addInput:deviceInput]; 
} 

AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:session]; 
[previewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill]; 
CALayer *rootLayer = [[self view] layer]; 
[rootLayer setMasksToBounds:YES]; 
CGRect frame = self.frameForCapture.frame; 
[previewLayer setFrame:frame]; 
[rootLayer insertSublayer:previewLayer atIndex:0]; 

stillImageOutput = [[AVCaptureStillImageOutput alloc] init]; 
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:AVVideoCodecJPEG, AVVideoCodecKey, nil]; 
[stillImageOutput setOutputSettings:outputSettings]; 
[session addOutput:stillImageOutput]; 

[session startRunning]; 

然後，以實際拍攝的圖像，你可以用一個按鈕具有以下代碼：

- (IBAction)takePhoto:(id)sender { 
    AVCaptureConnection *videoConnection = nil; 
    for (AVCaptureConnection *connection in stillImageOutput.connections) { 
     for (AVCaptureInputPort *port in [connection inputPorts]) { 
      if ([[port mediaType] isEqual:AVMediaTypeVideo]) { 
       videoConnection = connection; 
       break; 
      } 
     } 
     if (videoConnection) { 
      break; 
     } 
    } 
    [stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection 
                completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) { 
                 if (imageDataSampleBuffer != NULL) { 
                  NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer]; 
                  UIImage *image = [UIImage imageWithData:imageData]; 
                 } 
                }]; 
} 

然後，你可以做任何你想做的事情與保存的圖像。