AVAssetExportSession errors when exporting .m4a

Question

I'm able to record and play audio and though I'm trying to save the file after trimming, note that this function will re-save the file regardless of being trimmed. Here is the error being thrown.

failed Error Domain=AVFoundationErrorDomain Code=-11800 "The operation could not be completed" UserInfo={NSUnderlyingError=0x600001635aa0 {Error Domain=NSOSStatusErrorDomain Code=-16979 "(null)"}, NSLocalizedFailureReason=An unknown error occurred (-16979)

Here is my setup

var recordingURL: URL!
let fileName = "\(NSUUID().uuidString).m4a"

func startRecording() {
 recordingURL = FileManager.getDocumentsDirectory().appendingPathComponent(fileName)
    let settings = [
        AVFormatIDKey: Int(kAudioFormatMPEG4AAC),
        AVSampleRateKey: 12000,
        AVNumberOfChannelsKey: 1,
        AVEncoderAudioQualityKey: AVAudioQuality.high.rawValue
    ]
    do {
        audioRecorder = try AVAudioRecorder(url: recordingURL, settings:       settings)
        audioRecorder.delegate = self
        audioRecorder.record()
    } catch {
        finishRecording(success: false)
    }
}

func saveAudiofile() {
    let asset = AVAsset(url: recordingURL)
    exportAsset(asset) 
}

func exportAsset(_ asset: AVAsset) {
    let documentsDirectory = FileManager.getDocumentsDirectory()
    let fileURL = documentsDirectory.appendingPathComponent(fileName)
    print("Here is the file Path \(fileURL.path)")

    let filePath = fileURL.path
    let fileManager = FileManager.default
    if fileManager.fileExists(atPath: filePath) {
        do {
            try fileManager.removeItem(atPath: filePath)
        }
        catch {
            print("Couldn't remove existing destination file: \(error)")
        }
    }
    print("creating export session")

    if let exporter = AVAssetExportSession(asset: asset, presetName: AVAssetExportPresetAppleM4A) {
        exporter.outputFileType = AVFileType.m4a
        exporter.outputURL = fileURL


        if wastrimmed {
            let start = CMTime(seconds: startTime, preferredTimescale: 1)
            let stop = CMTime(seconds: endTime, preferredTimescale: 1)
            exporter.timeRange = CMTimeRangeFromTimeToTime(start: start, end: stop)
        } else {
            let startTime = CMTime(seconds: 0, preferredTimescale: 1)
            let endTime = CMTime(seconds: recordingSnapshot, preferredTimescale: 1)
            exporter.timeRange = CMTimeRangeFromTimeToTime(start: startTime, end: endTime)
            print("The duration is: \(exporter.timeRange.duration)")
        }

        let trimmedDuration = CMTimeGetSeconds(exporter.timeRange.duration)

        if trimmedDuration < 10.0 {
            print("Audio is not long enough: \(trimmedDuration)")
            return
        }

        exporter.exportAsynchronously(completionHandler: {
            switch exporter.status {
            case AVAssetExportSessionStatus.failed:
                print("failed \(exporter.error!)")
            case AVAssetExportSessionStatus.cancelled:
                print("cancelled \(exporter.error!)")
            case AVAssetExportSessionStatus.unknown:
                print("unknown\(exporter.error!)")
            case AVAssetExportSessionStatus.waiting:
                print("waiting\(exporter.error!)")
            case AVAssetExportSessionStatus.exporting:
                print("exporting\(exporter.error!)")
            default:
                print("complete")
                User.draftEpisodes?.append(self.fileName)
            }
        })
    } else {
        print("cannot create AVAssetExportSession for asset \(asset)")
    }
}

The output:

Success recording Here is the file Path /Users/waylansands/Library/Developer/CoreSimulator/Devices/E919B236-0B88-4CA4-A7EF-03E668AE716E/data/Containers/Data/Application/E6410C85-49EF-4F65-83D2-C470C166BBAE/Documents/16E8D6E6-DB81-48DA-8766-7A60981031EC.m4a

creating export session 2020-04-20 20:53:00.218660+1000 Dune[4381:496890] CMTimeMakeWithSeconds(11.173 seconds, timescale 1): warning: error of -0.173 introduced due to very low timescale

The duration is: CMTime(value: 11, timescale: 1, flags: __C.CMTimeFlags(rawValue: 3), epoch: 0)

failed Error Domain=AVFoundationErrorDomain Code=-11800 "The operation could not be completed" UserInfo={NSUnderlyingError=0x600001635aa0 {Error Domain=NSOSStatusErrorDomain Code=-16979 "(null)"}, NSLocalizedFailureReason=An unknown error occurred (-16979), NSURL=file:///Users/waylansands/Library/Developer/CoreSimulator/Devices/E919B236-0B88-4CA4-A7EF-03E668AE716E/data/Containers/Data/Application/E6410C85-49EF-4F65-83D2-C470C166BBAE/Documents/16E8D6E6-DB81-48DA-8766-7A60981031EC.m4a, NSLocalizedDescription=The operation could not be completed}

Found the problem, this works when I add the file extension as followed. — Waylan Sands

Waylan Sands Waylan Sands · Accepted Answer · 2020-04-21T11:45:04

Found the solution, this works when I add the file extension within my start recording function

recordingURL = FileManager.getDocumentsDirectory().appendingPathComponent(fileName + ".m4a")

AVAssetExportSession errors when exporting .m4a

1 Answers