IOS Video Compression Swift iOS 8 corrupt video file

Question

I am trying to compress video taken with the users camera from UIImagePickerController (Not an existing video but one on the fly) to upload to my server and take a small amo

Answer 1

Figured it out! Ok so there were 2 problems: 1 problem was with the videoWriter.finishWritingWithCompletionHandler function call. when this completion block gets executed it DOES NOT MEAN that the video writer has finished writing to the output url. So i had to check if the status was completed before i uploaded the actual video file. It's kind of a hack but this is what i did

   videoWriter.finishWritingWithCompletionHandler({() -> Void in

          while true
          {
            if videoWriter.status == .Completed 
            {
               var data = NSData(contentsOfURL: outputURL)!

               println("Finished: Byte Size After Compression: \(data.length / 1048576) mb")

               Networking().uploadVideo(data, fileName: "Video")

               self.dismissViewControllerAnimated(true, completion: nil)
               break
              }
            }
        })

The second problem I was having was a Failed status and that was because i kept writing to the same temp directory as shown in the code for the UIImagePickerController didFinishSelectingMediaWithInfo method in my question. So i just used the current date as a directory name so it would be unique.

var uploadUrl = NSURL.fileURLWithPath(NSTemporaryDirectory().stringByAppendingPathComponent("\(NSDate())").stringByAppendingString(".mov"))

[EDIT]: BETTER SOLUTION

Ok so after a lot of experimenting and months later I've found a damn good and much simpler solution for getting a video down from 45 mb down to 1.42 mb with pretty good quality.

Below is the function to call instead of the original convertVideo function. note that i had to write my own completion handler paramater which is called after the asynchronous export has finished. i just called it handler.

 func compressVideo(inputURL: NSURL, outputURL: NSURL, handler:(session: AVAssetExportSession)-> Void)
{
    var urlAsset = AVURLAsset(URL: inputURL, options: nil)

    var exportSession = AVAssetExportSession(asset: urlAsset, presetName: AVAssetExportPresetMediumQuality)

    exportSession.outputURL = outputURL

    exportSession.outputFileType = AVFileTypeQuickTimeMovie

    exportSession.shouldOptimizeForNetworkUse = true

    exportSession.exportAsynchronouslyWithCompletionHandler { () -> Void in

        handler(session: exportSession)
    }

}

And here is the code in the uiimagepickercontrollerDidFinisPickingMediaWithInfo function.

self.compressVideo(inputURL!, outputURL: uploadUrl!, handler: { (handler) -> Void in

                if handler.status == AVAssetExportSessionStatus.Completed
                {
                    var data = NSData(contentsOfURL: uploadUrl!)

                    println("File size after compression: \(Double(data!.length / 1048576)) mb")

                    self.picker.dismissViewControllerAnimated(true, completion: nil)


                }

                else if handler.status == AVAssetExportSessionStatus.Failed
                {
                        let alert = UIAlertView(title: "Uh oh", message: " There was a problem compressing the video maybe you can try again later. Error: \(handler.error.localizedDescription)", delegate: nil, cancelButtonTitle: "Okay")

                        alert.show()

                    })
                }
             })