UIImage from CMSampleBuffer has a blue tint

Question

I am displaying a video feed of CMSampleBuffers converted to UIImages inside a UIImageView. In the photo below, the background layer is an AVCapturePreviewLayer and the center is the buffer feed. My goal is to remove the blue tint.

Here is the CMSampleBuffer to UIImage code

extension CMSampleBuffer {
  func imageRepresentation() -> UIImage? {

    let imageBuffer: CVImageBufferRef = CMSampleBufferGetImageBuffer(self)!

    CVPixelBufferLockBaseAddress(imageBuffer, 0)
    let address = CVPixelBufferGetBaseAddressOfPlane(imageBuffer, 0)
    let bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer)
    let width = CVPixelBufferGetWidth(imageBuffer)
    let height = CVPixelBufferGetHeight(imageBuffer)

    let colorSpace = CGColorSpaceCreateDeviceRGB()

    let context = CGBitmapContextCreate(address, width, height, 8, bytesPerRow, colorSpace, CGImageAlphaInfo.NoneSkipFirst.rawValue)
    let imageRef = CGBitmapContextCreateImage(context)

    CVPixelBufferUnlockBaseAddress(imageBuffer, 0)
    let resultImage: UIImage = UIImage(CGImage: imageRef!)

    return resultImage
  }
}

AVCaptureVideoDataOutput setup:

class MovieRecorder: NSObject {
  // vars
  private let captureVideoDataOutput = AVCaptureVideoDataOutput()

  // capture session boilerplate setup...

  captureVideoDataOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey: Int(kCVPixelFormatType_32BGRA)]
  captureVideoDataOutput.alwaysDiscardsLateVideoFrames = true
  captureVideoDataOutput.setSampleBufferDelegate(self, queue: captureDataOutputQueue)
}

score 4 · Accepted Answer · answered Nov 24 '15 at 18:53

The problem was with the bitmapInfo. This bitmap info fixed it.

let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.NoneSkipFirst.rawValue | CGBitmapInfo.ByteOrder32Little.rawValue)
let context = CGBitmapContextCreate(address, width, height, 8, bytesPerRow, colorSpace, bitmapInfo.rawValue)

UIImage from CMSampleBuffer has a blue tint

1 Answers1