cg-image-creation.swift

func cgImageFromSampleBuffer(_ buffer: CMSampleBuffer) -> CGImage? {
    guard let pixelBuffer = CMSampleBufferGetImageBuffer(buffer) else {
        return nil
    }

    CVPixelBufferLockBaseAddress(pixelBuffer, .readOnly)

    let baseAddress = CVPixelBufferGetBaseAddress(pixelBuffer)
    let bytesPerRow = CVPixelBufferGetBytesPerRow(pixelBuffer)

    let width = CVPixelBufferGetWidth(pixelBuffer) // Preferably I'd like to hardcode this width
    let height = CVPixelBufferGetHeight(pixelBuffer) // and this height

    let context = CGContext(data: baseAddress, width: width, height: height, bitsPerComponent: 8, bytesPerRow: bytesPerRow, space: CGColorSpaceCreateDeviceRGB(), bitmapInfo: CGImageAlphaInfo.premultipliedFirst.rawValue)!

    let image = context.makeImage()!

    CVPixelBufferUnlockBaseAddress(pixelBuffer, .readOnly)

    return image
}