CMSampleBuffer extension to convert to UIImage: Too expensive on memory - ios

Question

I'm trying to convert a CMSampleBuffer to an UIImage with Swift 3.0. A popular solution is to write an extension for the CMSampleBuffer class and add a getter to convert the buffer to an image. This is what it looks like:
import Foundation
import AVFoundation
extension CMSampleBuffer {
#available(iOS 9.0, *)
var uiImage: UIImage? {
guard let imageBuffer = CMSampleBufferGetImageBuffer(self) else { return nil }
let ciimage: CIImage = CIImage(cvImageBuffer: imageBuffer)
let image:UIImage = UIImage(ciImage: ciimage)
return image
}
}
It works fine but it's taking up a lot of memory, 40% of the total app memory. Is there a more memory efficient solution?
EDIT:
I have changed my code and it looks like this:
var uiImage: UIImage? {
guard let imageBuffer = CMSampleBufferGetImageBuffer(self) else { return nil }
CVPixelBufferLockBaseAddress(imageBuffer, CVPixelBufferLockFlags(rawValue: 0))
let baseAddress = CVPixelBufferGetBaseAddress(imageBuffer)
let bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer)
let width = CVPixelBufferGetWidth(imageBuffer)
let height = CVPixelBufferGetHeight(imageBuffer)
let colorSpace = CGColorSpaceCreateDeviceRGB()
let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.noneSkipFirst.rawValue | CGBitmapInfo.byteOrder32Little.rawValue)
var image: UIImage?
autoreleasepool(invoking: {() -> () in
guard let context = CGContext(data: baseAddress,
width: width,
height: height,
bitsPerComponent: 8,
bytesPerRow: bytesPerRow,
space: colorSpace,
bitmapInfo: bitmapInfo.rawValue) else { return }
guard let cgImage = context.makeImage() else { return }
image = UIImage(cgImage: cgImage)
})
CVPixelBufferUnlockBaseAddress(imageBuffer,CVPixelBufferLockFlags(rawValue: 0));
return image
}
The memory leak has something to do with the CGContext. Is there any other way I can free/release/deallocate it besides using an autoreleasepool?