(Cocoa error -1) When attempting to save video created with AVCaptureSession - swift

Question

I'm generating a video using an AVCapture session and then using an AVVideoCompositionCoreAnimationTool to add a simple overlay. I then use an AVAssetExportSession to output the file. This all seems to work but then when I attempt to save it to the Photo Library using PHPhotoLibrary (because ALAssetsLibrary has been depreciated) is fails with the message:"Cant complete operation cocoa error -1". After extensive Google use and checking the docs I can't work out whats going wrong.
Any help would be great thanks.
func videoOutput() {
videoToMake = AVAsset(URL: videoToMakeURL!)
if (videoToMake == nil) {
return
}
//This holds the different tracks of the video like audio and the layers
let mixComposition = AVMutableComposition()
let videoTrack = mixComposition.addMutableTrackWithMediaType(AVMediaTypeVideo, preferredTrackID: Int32(kCMPersistentTrackID_Invalid))
print("The duration of the video to create is \(videoToMake!.duration.seconds)")
do{
try videoTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero,videoToMake!.duration), ofTrack: videoToMake!.tracksWithMediaType(AVMediaTypeVideo)[0], atTime: kCMTimeZero)
}catch let error as NSError{
print("Error inserting time range on video track \(error.localizedDescription)")
return
}catch{
print("An unknown error occured")
}
//Make the instructions for the other layers
let mainInstrucation = AVMutableVideoCompositionInstruction()
mainInstrucation.timeRange = CMTimeRangeMake(kCMTimeZero, videoToMake!.duration)
//Create the layer instructions
let videoLayerInstruction = AVMutableVideoCompositionLayerInstruction(assetTrack: videoTrack)
let videoAssetTrack = videoToMake!.tracksWithMediaType(AVMediaTypeVideo)[0]
let assetInfo = orientationFromTransform(videoAssetTrack.preferredTransform)
// sort size it in respect to the video orientation.
videoLayerInstruction.setTransform(videoAssetTrack.preferredTransform, atTime: kCMTimeZero)
videoLayerInstruction.setOpacity(0.0, atTime:videoToMake!.duration)
//Add the instructions
mainInstrucation.layerInstructions = [videoLayerInstruction]
let mainCompositionInst = AVMutableVideoComposition()
var naturalSize:CGSize
if assetInfo.isPortrait {
naturalSize = CGSizeMake(videoAssetTrack.naturalSize.height, videoAssetTrack.naturalSize.width);
}else{
naturalSize = videoAssetTrack.naturalSize
}
let renderWidth = naturalSize.width
let renderHeight = naturalSize.height
mainCompositionInst.renderSize = CGSizeMake(renderWidth, renderHeight)
mainCompositionInst.instructions = [mainInstrucation]
mainCompositionInst.frameDuration = CMTimeMake(1, 30);
//So now the main composition has been created add the video affects
applyVideoEffectsToComposition(mainCompositionInst, size: naturalSize)
let paths = NSSearchPathForDirectoriesInDomains(.DocumentDirectory,.UserDomainMask, true)
let documentsDirectory = paths[0]
let random = Int(arc4random_uniform(1000))
let url = NSURL(fileURLWithPath:documentsDirectory).URLByAppendingPathComponent("FinalVideo\(random)")
//Create the exporter
let exporter = AVAssetExportSession(asset: mixComposition, presetName:AVAssetExportPresetHighestQuality)
exporter!.outputURL = url
exporter!.outputFileType = AVFileTypeMPEG4
exporter!.shouldOptimizeForNetworkUse = true
exporter!.videoComposition = mainCompositionInst
//Perform the export
exporter!.exportAsynchronouslyWithCompletionHandler() {
dispatch_async(dispatch_get_main_queue(), { () -> Void in
self.exportDidFinish(exporter!)
})
}
}

Answer 1

Well it turns out I was missing the extension from the end of my movie name:
let url = NSURL(fileURLWithPath:documentsDirectory).URLByAppendingPathComponent("FinalVideo\(random)")
So it should have been "FinalVideo(random).mov"
Hope this helps somebody one day.