To understand pixelBufferFromCGImage with Swift

I have 2 problems. one is black screen and another is abnormal pxbuffer image.

black screen problem is because Changing UIImage to CGImage.

abnormal pxbuffer image problem is below.

left one is abnormal pxbuffer image, right one is source image.

The cause was bytesPerRow.

I tested an image with 100px image. but pxbuffer's bytesPerRow was 448.

So I solved like below. (source: https://github.com/seoddong/SamplePixelBuffer)

//
//  File.swift
//  BurstAnimator
//
//  Created by SeoDongHee on 2016. 5. 2..
//  Copyright © 2016년 SeoDongHee. All rights reserved.
//

import Foundation
import AVFoundation
import UIKit

class ImagesToVideo {
    
    var sender: AnyObject
    
    init(sender: AnyObject) {
        self.sender = sender
    }
    
    
    func pixelBufferFromImage(image: UIImage) {
        var outputSize: CGSize
        
        outputSize = CGSizeMake(image.size.width, image.size.height)
        
        debugPrint("arrayImages[0] = \(image)")
        debugPrint("outputSize = \(outputSize)")
        
        let tempPath = NSTemporaryDirectory().stringByAppendingString("temp.mp4")
        do {
            try NSFileManager.defaultManager().removeItemAtPath(tempPath)
            debugPrint("removeItemAtPath = success..")
        }
        catch {
            debugPrint("removeItemAtPath = error occured...")
        }
        // It's not easy that "Change UIImage to CGImage", if you would try even to change NSArray to CGImage, you get black screen finally. so you have to step below.
        let ciimage = CIImage(image: image)
        let cgimage = convertCIImageToCGImage(ciimage!)

        /*
         NSDictionary *options = @{(id)kCVPixelBufferCGImageCompatibilityKey: @YES,
         (id)kCVPixelBufferCGBitmapContextCompatibilityKey: @YES};
        */
        // stupid CFDictionary stuff
        let cfnumPointer = UnsafeMutablePointer>.alloc(1)
        let cfnum = CFNumberCreate(kCFAllocatorDefault, .IntType, cfnumPointer)
        let keys: [CFStringRef] = [kCVPixelBufferCGImageCompatibilityKey, kCVPixelBufferCGBitmapContextCompatibilityKey, kCVPixelBufferBytesPerRowAlignmentKey]
        let values: [CFTypeRef] = [kCFBooleanTrue, kCFBooleanTrue, cfnum]
        let keysPointer = UnsafeMutablePointer>.alloc(1)
        let valuesPointer =  UnsafeMutablePointer>.alloc(1)
        keysPointer.initialize(keys)
        valuesPointer.initialize(values)

        let options = CFDictionaryCreate(kCFAllocatorDefault, keysPointer, valuesPointer, keys.count, nil, nil)


        let width = CGImageGetWidth(cgimage)
        let height = CGImageGetHeight(cgimage)
        
        let pxbuffer = UnsafeMutablePointer.alloc(1)
        // if pxbuffer = nil, you will get status = -6661
        var status = CVPixelBufferCreate(kCFAllocatorDefault, width, height,
                                         kCVPixelFormatType_32ARGB, options, pxbuffer)
        debugPrint("status = \(status)")
        status = CVPixelBufferLockBaseAddress(pxbuffer.memory!, 0);
        
        let bufferAddress = CVPixelBufferGetBaseAddress(pxbuffer.memory!);
        debugPrint("pxbuffer.memory = \(pxbuffer.memory)")
        
        let rgbColorSpace = CGColorSpaceCreateDeviceRGB();
        //debugPrint("rgbColorSpace = \(rgbColorSpace)")
        let bytesperrow = CVPixelBufferGetBytesPerRow(pxbuffer.memory!)
        let context = CGBitmapContextCreate(bufferAddress, width,
                                            height, 8, bytesperrow, rgbColorSpace,
                                            CGImageAlphaInfo.NoneSkipFirst.rawValue);
        //debugPrint("context = \(context.debugDescription)")
        CGContextDrawImage(context, CGRectMake(0, 0, CGFloat(width), CGFloat(height)), cgimage);
        

        // check context
        if let contextImage = CGBitmapContextCreateImage(context) {
            let checkImage1 = UIImage.init(CGImage: contextImage)
            let parentVC = sender as! ViewController
            //parentVC.imageview.image = checkImage1
            
            let checkImage2 = CIImage.init(CVPixelBuffer: pxbuffer.memory!)
            parentVC.imageview.image = UIImage.init(CIImage: checkImage2)
            
            //UIImageWriteToSavedPhotosAlbum(checkImage1, nil, nil, nil)
            //debugPrint("save..")
        }
        else {
            debugPrint("why context is null?")
        }

        status = CVPixelBufferUnlockBaseAddress(pxbuffer.memory!, 0);
        
    }
    
    func convertCIImageToCGImage(inputImage: CIImage) -> CGImage! {
        let context = CIContext(options: nil)
        
        return context.createCGImage(inputImage, fromRect: inputImage.extent)

    }

    /*
    // below is for debug, it's not working
    func drawOutput(pixelbuffer: UnsafeMutablePointer, width: Int, height: Int) {
        let pixels = pixelbuffer
        for var ii in 0...height {
            for var jj in 0...width {
                let color = pixels.memory! as Int
                print("\(r8(color)+g8(color)+b8(color)/3.0)")
                pixels ++
            }
            print("\n");
        }
    }
    func mask8(int: Int) -> Int {
        return int & 0xFF
    }
    func r8(int: Int) -> Int {
        return mask8(int)
    }
    func g8(int: Int) -> Int {
        return mask8(int) >> 8
    }
    func b8(int: Int) -> Int {
        return mask8(int) >> 16
    }
    */
    
}