Video export incorrect video's length in Swift - ios

Question

I Have created Video successfully from array of images with frame time duration = 1 second for all images. but I want to use different duration time for each of images, exp : 0.1s, 0.2s But It's not work correctly.
while (!self.selectedPhotosArray.isEmpty) {
if (videoWriterInput.isReadyForMoreMediaData) {
let nextDicData = self.selectedPhotosArray.remove(at: 0)
if let nextImage = nextDicData["img"] as? UIImage
{
var frameDuration = CMTimeMake(Int64(0 * 10000), fps)
if let timeVl = nextDicData["time"] as? Float{
framePerSecond = Int64(timeVl * 10000)
}
frameDuration = CMTimeMake(framePerSecond ,fps)
let lastFrameTime = CMTimeMake(Int64(lastTimeVl), fps)
let presentationTime = frameCount == 0 ? lastFrameTime : CMTimeAdd(lastFrameTime, frameDuration)
var pixelBuffer: CVPixelBuffer? = nil
let status: CVReturn = CVPixelBufferPoolCreatePixelBuffer(kCFAllocatorDefault, pixelBufferAdaptor.pixelBufferPool!, &pixelBuffer)
if let pixelBuffer = pixelBuffer, status == 0 {
let managedPixelBuffer = pixelBuffer
CVPixelBufferLockBaseAddress(managedPixelBuffer, CVPixelBufferLockFlags(rawValue: CVOptionFlags(0)))
let data = CVPixelBufferGetBaseAddress(managedPixelBuffer)
let rgbColorSpace = CGColorSpaceCreateDeviceRGB()
let context = CGContext(data: data, width: Int(self.outputSize.width), height: Int(self.outputSize.height), bitsPerComponent: 8, bytesPerRow: CVPixelBufferGetBytesPerRow(managedPixelBuffer), space: rgbColorSpace, bitmapInfo: CGImageAlphaInfo.premultipliedFirst.rawValue)
context!.clear(CGRect(x: 0, y: 0, width: CGFloat(self.outputSize.width), height: CGFloat(self.outputSize.height)))
let horizontalRatio = CGFloat(self.outputSize.width) / nextImage.size.width
let verticalRatio = CGFloat(self.outputSize.height) / nextImage.size.height
//let aspectRatio = max(horizontalRatio, verticalRatio) // ScaleAspectFill
let aspectRatio = min(horizontalRatio, verticalRatio) // ScaleAspectFit
let newSize: CGSize = CGSize(width: nextImage.size.width, height: nextImage.size.height)
let x = newSize.width < self.outputSize.width ? (self.outputSize.width - newSize.width) / 2 : 0
let y = newSize.height < self.outputSize.height ? (self.outputSize.height - newSize.height) / 2 : 0
context?.draw(nextImage.cgImage!, in: CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height))
CVPixelBufferUnlockBaseAddress(managedPixelBuffer, CVPixelBufferLockFlags(rawValue: CVOptionFlags(0)))
appendSucceeded = pixelBufferAdaptor.append(pixelBuffer, withPresentationTime: presentationTime)
} else {
print("Failed to allocate pixel buffer")
appendSucceeded = false
}
}
}
if !appendSucceeded {
break
}
frameCount += 1
lastTimeVl += framePerSecond
}