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High Performance CVPixelBuffer capture in Xamarin
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Video Capture | |
previewLayer = new AVCaptureVideoPreviewLayer(captureSession); | |
//previewLayer.VideoGravity = AVLayerVideoGravity.ResizeAspectFill; | |
previewView.Layer.AddSublayer(previewLayer); | |
previewView.TranslatesAutoresizingMaskIntoConstraints = false; | |
var previewConstraints = new[] | |
{ | |
previewView.LeftAnchor.ConstraintEqualTo(View.LeftAnchor), | |
previewView.RightAnchor.ConstraintEqualTo(View.RightAnchor), | |
previewView.TopAnchor.ConstraintEqualTo(View.TopAnchor), | |
previewView.BottomAnchor.ConstraintEqualTo(View.BottomAnchor) | |
}; | |
NSLayoutConstraint.ActivateConstraints(previewConstraints); | |
topBlurView.TranslatesAutoresizingMaskIntoConstraints = false; | |
bottomBlurView.TranslatesAutoresizingMaskIntoConstraints = false; | |
var topBlurConstraints = new[] | |
{ | |
topBlurView.LeftAnchor.ConstraintEqualTo(View.LeftAnchor), | |
topBlurView.RightAnchor.ConstraintEqualTo(View.RightAnchor), | |
topBlurView.TopAnchor.ConstraintEqualTo(View.TopAnchor), | |
topBlurView.HeightAnchor.ConstraintEqualTo(150) | |
}; | |
var bottomBlurConstraints = new[] | |
{ | |
bottomBlurView.LeftAnchor.ConstraintEqualTo(View.LeftAnchor), | |
bottomBlurView.RightAnchor.ConstraintEqualTo(View.RightAnchor), | |
bottomBlurView.BottomAnchor.ConstraintEqualTo(View.BottomAnchor), | |
bottomBlurView.HeightAnchor.ConstraintEqualTo(150) | |
}; | |
NSLayoutConstraint.ActivateConstraints(topBlurConstraints); | |
NSLayoutConstraint.ActivateConstraints(bottomBlurConstraints); | |
topBlurView.BackgroundColor = UIColor.Orange; | |
bottomBlurView.BackgroundColor = UIColor.Blue; | |
previewView.BackgroundColor = UIColor.Red; | |
View.SendSubviewToBack(previewView); |
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// called 60 times per second (60fps) | |
unsafe void DisplayBackground(CVPixelBuffer capturedImage) | |
{ | |
capturedImage.Lock(CVPixelBufferLock.None); | |
var baseAddress = capturedImage.BaseAddress; | |
var format = capturedImage.PixelFormatType; //CV420YpCbCr8BiPlanarFullRange | |
var width = (int)capturedImage.Width; //1280 | |
var height = (int)capturedImage.Height; //720 | |
cameraTexture.SetData(0, 0, 0, width, height, (void*)baseAddress); | |
capturedImage.Unlock(CVPixelBufferLock.None); | |
//Workaround #1: | |
//CVPixelBufferRelease(capturedImage.Handle); | |
//GC.SuppressFinalize(capturedImage); | |
//Workaround #2: | |
GC.Collect(); | |
} | |
[DllImport("/System/Library/Frameworks/CoreVideo.framework/CoreVideo")] | |
private static extern void CVPixelBufferRelease(IntPtr handle); |
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