Error NSLocalizedDescription=Cannot Save

Question

I was trying to merge audio and Video. I was following this link. I am getting a error but I don't understand what's wrong.

failed Optional(Error Domain=AVFoundationErrorDomain Code=-11823 "Cannot Save" UserInfo={NSLocalizedDescription=Cannot Save, NSLocalizedRecoverySuggestion=Try saving again.})

This my code:

import UIKit
import AVFoundation
import AVKit
import AssetsLibrary

class ViewController: UIViewController {
    func mergeFilesWithUrl(videoUrl:NSURL, audioUrl:NSURL)
    {
        let mixComposition : AVMutableComposition = AVMutableComposition()
        var mutableCompositionVideoTrack : [AVMutableCompositionTrack] = []
        var mutableCompositionAudioTrack : [AVMutableCompositionTrack] = []
        let totalVideoCompositionInstruction : AVMutableVideoCompositionInstruction = AVMutableVideoCompositionInstruction()

        //start merge
        let aVideoAsset : AVAsset = AVAsset(url: videoUrl as URL)
        let aAudioAsset : AVAsset = AVAsset(url: audioUrl as URL)

        mutableCompositionVideoTrack.append(mixComposition.addMutableTrack(withMediaType: AVMediaTypeVideo, preferredTrackID: kCMPersistentTrackID_Invalid))
        mutableCompositionAudioTrack.append( mixComposition.addMutableTrack(withMediaType: AVMediaTypeAudio, preferredTrackID: kCMPersistentTrackID_Invalid))

        let aVideoAssetTrack : AVAssetTrack = aVideoAsset.tracks(withMediaType: AVMediaTypeVideo)[0]
        let aAudioAssetTrack : AVAssetTrack = aAudioAsset.tracks(withMediaType: AVMediaTypeAudio)[0]

        do{
            try mutableCompositionVideoTrack[0].insertTimeRange(CMTimeRangeMake(kCMTimeZero, aVideoAssetTrack.timeRange.duration), of: aVideoAssetTrack, at: kCMTimeZero)

            //In my case my audio file is longer then video file so i took videoAsset duration
            //instead of audioAsset duration

            try mutableCompositionAudioTrack[0].insertTimeRange(CMTimeRangeMake(kCMTimeZero, aVideoAssetTrack.timeRange.duration), of: aAudioAssetTrack, at: kCMTimeZero)

            //Use this instead above line if your audiofile and video file's playing durations are same

            //            try mutableCompositionAudioTrack[0].insertTimeRange(CMTimeRangeMake(kCMTimeZero, aVideoAssetTrack.timeRange.duration), ofTrack: aAudioAssetTrack, atTime: kCMTimeZero)
        }catch{
        }

        totalVideoCompositionInstruction.timeRange = CMTimeRangeMake(kCMTimeZero,aVideoAssetTrack.timeRange.duration )

        let mutableVideoComposition : AVMutableVideoComposition = AVMutableVideoComposition()
        mutableVideoComposition.frameDuration = CMTimeMake(1, 30)
        mutableVideoComposition.renderSize = CGSize(width: 1280, height: 720)

        //find your video on this URl
        let savePathUrl : NSURL = NSURL(fileURLWithPath: NSHomeDirectory() + "/Documents/newVideo.mp4")

        let assetExport: AVAssetExportSession = AVAssetExportSession(asset: mixComposition, presetName: AVAssetExportPresetHighestQuality)!
        assetExport.outputFileType = AVFileTypeMPEG4
        assetExport.outputURL = savePathUrl as URL
        assetExport.shouldOptimizeForNetworkUse = true

        assetExport.exportAsynchronously { () -> Void in
            switch assetExport.status {

            case AVAssetExportSessionStatus.completed:
                //Uncomment this if u want to store your video in asset
                //let assetsLib = ALAssetsLibrary()
                //assetsLib.writeVideoAtPathToSavedPhotosAlbum(savePathUrl, completionBlock: nil)

                print("success")
            case  AVAssetExportSessionStatus.failed:
                print("failed \(String(describing: assetExport.error))")
            case AVAssetExportSessionStatus.cancelled:
                print("cancelled \(String(describing: assetExport.error))")
            default:
                print("complete")
            }
        }
    }

    @IBAction func marge(_ sender: Any) {
        let videoUrl : NSURL =  NSURL(fileURLWithPath: Bundle.main.path(forResource: "desp", ofType: "mp4")!)
        let audioUrl : NSURL = NSURL(fileURLWithPath: Bundle.main.path(forResource: "Desp", ofType: "mp3")!)

        mergeFilesWithUrl(videoUrl: videoUrl, audioUrl: audioUrl)
    }
}

This happens typically when there is already a file existing at the output URL. Check for the file before starting the export session and delete or modify it if necessary. — Nareshkumar, Jan 22 '18 at 09:24

score 29 · Answer 1 · answered Jul 10 '18 at 03:43

29

I ran into this problem, too. Try to add these couple lines of code and it shall solve the problem.

do { // delete old video
        try FileManager.default.removeItem(at: savePathUrl)
    } catch { print(error.localizedDescription) }

It will delete the old file in this directory.

answered Jul 10 '18 at 03:43

Bo Ni

575
6
10

9

One of the most disgusting things about how Apple create on purpose, crap APIs, is why the error does not say "cannot overwrite file", or "file already exists with that name" and why the API does not offer the overwrite option. Instead it displays "Error 11823, cannot save file" and screw the developer. – Duck Jul 19 '20 at 03:02
1

best comment I've ever read in StackOverFlow ^^^ – BennyTheNerd May 27 '21 at 19:03

Error NSLocalizedDescription=Cannot Save

1 Answers1