Question

我试图在拍摄图像后直接访问像素数据。因此我想我需要CVImageBufferRef，但它总是0x00000000为什么？

    [stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error)
 {
     if(imageSampleBuffer){

         CVImageBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(imageSampleBuffer);
         CVPixelBufferLockBaseAddress(pixelBuffer, 0);

由于

Answer 1

您必须设置kCVPixelBufferPixelFormatTypeKey的outputSettings的键AVCaptureStillImageOutput：

  _stillImageOutput = [AVCaptureStillImageOutput new];
  NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:[NSNumber numberWithUnsignedInt:kCVPixelFormatType_420YpCbCr8BiPlanarFullRange], kCVPixelBufferPixelFormatTypeKey, nil];
  [_stillImageOutput setOutputSettings:outputSettings];

  if ([_captureSession canAddOutput:_stillImageOutput])
    [_captureSession addOutput:_stillImageOutput];

要设置两个可能的键(AVVideoCodecKey and kCVPixelBufferPixelFormatTypeKey)，但它们是互斥的。（在iOS 6及更高版本中，如果使用AVVideoCodecKey，还可以设置图像质量键AVVideoQualityKey。）

无法在captureStillImageAsynchronouslyFromConnection中获取CVImageBufferRef？

1 个答案: