iOS Audio Trimming

iOS Audio Trimming

Here's the code that I've used to trim audio from a pre-existing file. You'll need to change the M4A related constants if you've saved or are saving to another format.

- (BOOL)trimAudio
{
    float vocalStartMarker = <starting time>;
    float vocalEndMarker = <ending time>;

    NSURL *audioFileInput = <your pre-existing file>;
    NSURL *audioFileOutput = <the file you want to create>;

    if (!audioFileInput || !audioFileOutput)
    {
        return NO;
    }

    [[NSFileManager defaultManager] removeItemAtURL:audioFileOutput error:NULL];
    AVAsset *asset = [AVAsset assetWithURL:audioFileInput];

    AVAssetExportSession *exportSession = [AVAssetExportSession exportSessionWithAsset:asset
                                                                            presetName:AVAssetExportPresetAppleM4A];

    if (exportSession == nil)
    {        
        return NO;
    }

    CMTime startTime = CMTimeMake((int)(floor(vocalStartMarker * 100)), 100);
    CMTime stopTime = CMTimeMake((int)(ceil(vocalEndMarker * 100)), 100);
    CMTimeRange exportTimeRange = CMTimeRangeFromTimeToTime(startTime, stopTime);

    exportSession.outputURL = audioFileOutput;
    exportSession.outputFileType = AVFileTypeAppleM4A;
    exportSession.timeRange = exportTimeRange;

    [exportSession exportAsynchronouslyWithCompletionHandler:^
     {
         if (AVAssetExportSessionStatusCompleted == exportSession.status)
         {
             // It worked!
         } 
         else if (AVAssetExportSessionStatusFailed == exportSession.status)
         {
             // It failed...
         }
     }];

    return YES;
}

There's also Technical Q&A 1730, which gives a slightly more detailed approach.

iOS: trimming audio files with Swift?

Finally I find the answer for my question.It's working fine...I attached the code below. I added the trim audio code in it.It will be useful for those who are trying to merge and trim the audio(swift2.3):

func mixAudio()
{
    let currentTime = CFAbsoluteTimeGetCurrent()
    let composition = AVMutableComposition()
    let compositionAudioTrack = composition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: kCMPersistentTrackID_Invalid)
    compositionAudioTrack.preferredVolume = 0.8
    let avAsset = AVURLAsset.init(URL: soundFileURL, options: nil)
    print("\(avAsset)")
    var tracks = avAsset.tracksWithMediaType(AVMediaTypeAudio)
    let clipAudioTrack = tracks[0]
    do {
        try compositionAudioTrack.insertTimeRange(CMTimeRangeMake(kCMTimeZero, avAsset.duration), ofTrack: clipAudioTrack, atTime: kCMTimeZero)
    }
    catch _ {
    }
    let compositionAudioTrack1 = composition.addMutableTrackWithMediaType(AVMediaTypeAudio, preferredTrackID: kCMPersistentTrackID_Invalid)
    compositionAudioTrack.preferredVolume = 0.8

    let avAsset1 = AVURLAsset.init(URL: soundFileURL1)
    print(avAsset1)


    var tracks1 = avAsset1.tracksWithMediaType(AVMediaTypeAudio)
    let clipAudioTrack1 = tracks1[0]
    do {
        try compositionAudioTrack1.insertTimeRange(CMTimeRangeMake(kCMTimeZero, avAsset1.duration), ofTrack: clipAudioTrack1, atTime: kCMTimeZero)
    }
    catch _ {
    }
    var paths = NSSearchPathForDirectoriesInDomains(.LibraryDirectory, .UserDomainMask, true)
    let CachesDirectory = paths[0]
    let strOutputFilePath = CachesDirectory.stringByAppendingString("/Fav")
    print(" strOutputFilePath is \n \(strOutputFilePath)")

    let requiredOutputPath = CachesDirectory.stringByAppendingString("/Fav.m4a")
    print(" requiredOutputPath is \n \(requiredOutputPath)")

    soundFile1 = NSURL.fileURLWithPath(requiredOutputPath)
    print(" OUtput path is \n \(soundFile1)")
    var audioDuration = avAsset.duration
    var totalSeconds = CMTimeGetSeconds(audioDuration)
    var hours = floor(totalSeconds / 3600)
    var minutes = floor(totalSeconds % 3600 / 60)
    var seconds = Int64(totalSeconds % 3600 % 60)
    print("hours = \(hours), minutes = \(minutes), seconds = \(seconds)")

    let recordSettings:[String : AnyObject] = [

        AVFormatIDKey: Int(kAudioFormatMPEG4AAC),
        AVSampleRateKey: 12000,
        AVNumberOfChannelsKey: 1,
        AVEncoderAudioQualityKey: AVAudioQuality.Low.rawValue
    ]
    do {
        audioRecorder = try AVAudioRecorder(URL: soundFile1, settings: recordSettings)
        audioRecorder!.delegate = self
        audioRecorder!.meteringEnabled = true
        audioRecorder!.prepareToRecord()
    }

    catch let error as NSError
    {
        audioRecorder = nil
        print(error.localizedDescription)
    }

    do {

        try NSFileManager.defaultManager().removeItemAtURL(soundFile1)
    }
    catch _ {
    }
    let exporter = AVAssetExportSession(asset: composition, presetName: AVAssetExportPresetAppleM4A)
    exporter!.outputURL = soundFile1
    exporter!.outputFileType = AVFileTypeAppleM4A
    let duration = CMTimeGetSeconds(avAsset1.duration)
    print(duration)
    if (duration < 5.0) {
        print("sound is not long enough")
        return
    }
    // e.g. the first 30 seconds
    let startTime = CMTimeMake(0, 1)
    let stopTime = CMTimeMake(seconds,1)
    let exportTimeRange = CMTimeRangeFromTimeToTime(startTime, stopTime)
    print(exportTimeRange)
    exporter!.timeRange = exportTimeRange
    print(exporter!.timeRange)


    exporter!.exportAsynchronouslyWithCompletionHandler
        {() -> Void in
            print(" OUtput path is \n \(requiredOutputPath)")
            print("export complete: \(CFAbsoluteTimeGetCurrent() - currentTime)")
            var url:NSURL?
            if self.audioRecorder != nil
            {
                url = self.audioRecorder!.url
            }

            else
            {
                url = self.soundFile1!
                print(url)

            }

            print("playing \(url)")

    do
    {
        print(self.soundFile1)
        print(" OUtput path is \n \(requiredOutputPath)")
        self.setSessionPlayback()
        do {
                                        self.optData = try NSData(contentsOfURL: self.soundFile1!, options: NSDataReadingOptions.DataReadingMappedIfSafe)
                                        print(self.optData)
                                        self.recordencryption = self.optData.base64EncodedStringWithOptions(NSDataBase64EncodingOptions())

                                        //  print(self.recordencryption)
                                          self.myImageUploadRequest()


                                    }



        self.wasteplayer = try AVAudioPlayer(contentsOfURL: self.soundFile1)
        self.wasteplayer.numberOfLoops = 0
        self.wasteplayer.play()


    }

    catch _
    {
    }

    }
}

Audio cutter native iOS element

UI element for audio wave - https://stackoverflow.com/a/64709493/13296047. This post answers exactly how to create a audio wave from recorded audio.

UI element for cutting an audio wave - https://stackoverflow.com/a/52062837/13296047

UI element in the bottom for audio cutting feature - https://stackoverflow.com/a/40670853/13296047

This is a very good Voice Memos clone you can use for reference: https://github.com/HassanElDesouky/VoiceMemosClone

How I can add a audio trim on audio file which is stored on FileManager in swift iOS?

This solved my problem.

 func trimSelectedAudio(){ 

    let name = browseData.name!
    if let asset = AVURLAsset(url: getDirectory().appendingPathComponent("\(tfTitle.text!).m4a")) as? AVAsset{
        exportAsset(asset, fileName: name)
    }
}

func exportAsset(_ asset: AVAsset, fileName:String){
    let trimmedSoundFileUrl = getDirectory().appendingPathComponent("\(tfTitle.text!)_trimmed.m4a")
            print("Saving to \(trimmedSoundFileUrl.absoluteString)")


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

        let duration = CMTimeGetSeconds(asset.duration)
        if duration < 5.0{
            print("Audio is not song long")
            return
        }
        let startTime = CMTimeMake(Int64(selectAudioRange.selectedMinValue), 1)
        let stopTime = CMTimeMake(Int64(selectAudioRange.selectedMaxValue), 1)
        exporter.timeRange = CMTimeRangeFromTimeToTime(startTime, stopTime)

        exporter.exportAsynchronously(completionHandler: {
            print("export complete \(exporter.status)")

            switch exporter.status {
            case  AVAssetExportSessionStatus.failed:

                if let e = exporter.error {
                    print("export failed \(e)")
                }

            case AVAssetExportSessionStatus.cancelled:
                print("export cancelled \(String(describing: exporter.error))")
            default:
                print("export complete")
                self.deleteFileAlreadyPresent()
                // change core data data here
            }
        })
    } else{
        print("cannot create AVAssetExportSession for asset \(asset)")
    }
}

func deleteFileAlreadyPresent(){
    let PresentAudioUrl = getDirectory().appendingPathComponent("\(previousAudioName).m4a")
            if FileManager.default.fileExists(atPath: PresentAudioUrl.path){
                print("Sound exists, removing \(PresentAudioUrl.path)")
                do{
                    if try PresentAudioUrl.checkResourceIsReachable(){
                        print("is reachable")
                        self.deleteRecordingFile(audioName: "\(previousAudioName).m4a")
                        self.saveTrimmedData()
                    }
                   // try FileManager.default.removeItem(atPath: trimmedSoundFileUrl.absoluteString)
                } catch{
                    print("Could not remove \(PresentAudioUrl.absoluteString)")
                }
            }
}

func saveTrimmedData(){
    DispatchQueue.main.async {
        self.browseData.image = (self.imgToSave.image?.jpeg!)!
        self.browseData.note = self.tfNotes.text
         self.browseData.name = "\(self.tfTitle.text!)_trimmed"



    do{
        try self.context.save()
        self.goToParentVC()

    } catch let error as NSError{
        print("Could not save \(error) \(error.userInfo)")
    }

         }
}

Trim audio with iOS

How about using the AVFoundation? Import the audio file into an AVAsset (composition etc), then you can export it - setting preferred time + duration - to a file.

I wrote a stock function awhile ago that exports an asset to a file, you can also specify an audiomix. As below it exports all of the file, but you could add a NSTimeRange to exporter.timeRange and there you go. I haven't tested that though, but should work(?). Another alternative could be to adjust time ranges when creating the AVAsset + tracks. Of course the exporter only handles m4a (AAC). Sorry if this wasn't what you wanted.

-(void)exportAsset:(AVAsset*)asset toFile:(NSString*)filename overwrite:(BOOL)overwrite withMix:(AVAudioMix*)mix {
//NSArray* availablePresets = [AVAssetExportSession exportPresetsCompatibleWithAsset:asset];

AVAssetExportSession* exporter = [AVAssetExportSession exportSessionWithAsset:asset presetName:AVAssetExportPresetAppleM4A];

if (exporter == nil) {
    DLog(@"Failed creating exporter!");
    return;
}

DLog(@"Created exporter! %@", exporter);

// Set output file type
DLog(@"Supported file types: %@", exporter.supportedFileTypes);
for (NSString* filetype in exporter.supportedFileTypes) {
    if ([filetype isEqualToString:AVFileTypeAppleM4A]) {
        exporter.outputFileType = AVFileTypeAppleM4A;
        break;
    }
}
if (exporter.outputFileType == nil) {
    DLog(@"Needed output file type not found? (%@)", AVFileTypeAppleM4A);
    return;
}

// Set outputURL
NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString* parentDir = [NSString stringWithFormat:@"%@/", [paths objectAtIndex:0]];

NSString* outPath = [NSString stringWithFormat:@"%@%@", parentDir, filename];

NSFileManager* manager = [NSFileManager defaultManager];
if ([manager fileExistsAtPath:outPath]) {
    DLog(@"%@ already exists!", outPath);
    if (!overwrite) {
        DLog(@"Not overwriting, uh oh!");
        return;
    }
    else {
        // Overwrite
        DLog(@"Overwrite! (delete first)");
        NSError* error = nil;
        if (![manager removeItemAtPath:outPath error:&error]) {
            DLog(@"Failed removing %@, error: %@", outPath, error.description);
            return;
        }
        else {
            DLog(@"Removed %@", outPath);
        }
    }
}

NSURL* const outUrl = [NSURL fileURLWithPath:outPath];
exporter.outputURL = outUrl;
// Specify a time range in case only part of file should be exported
//exporter.timeRange =

if (mix != nil)
    exporter.audioMix = mix; // important

DLog(@"Starting export! (%@)", exporter.outputURL);
[exporter exportAsynchronouslyWithCompletionHandler:^(void) {
    // Export ended for some reason. Check in status
    NSString* message;
    switch (exporter.status) {
        case AVAssetExportSessionStatusFailed:
            message = [NSString stringWithFormat:@"Export failed. Error: %@", exporter.error.description];
            DLog(@"%@", message);
            [self showAlert:message];
            break;
        case AVAssetExportSessionStatusCompleted: {
            /*if (playfileWhenExportFinished) {
             DLog(@"playfileWhenExportFinished!");
             [self playfileAfterExport:exporter.outputURL];
             playfileWhenExportFinished = NO;
             }*/
            message = [NSString stringWithFormat:@"Export completed: %@", filename];
            DLog(@"%@", message);
            [self showAlert:message];
            break;
        }
        case AVAssetExportSessionStatusCancelled:
            message = [NSString stringWithFormat:@"Export cancelled!"];
            DLog(@"%@", message);
            [self showAlert:message];
            break;
        default:
            DLog(@"Export unhandled status: %d", exporter.status);
            break;
    }       
}];
}

Audiokit trim audio

Export asynchronously allows for setting the start and end samples:

https://github.com/AudioKit/AudioKit/blob/master/AudioKit/Common/Internals/Audio%20File/AKAudioFile%2BProcessingAsynchronously.swift#L267

/// Exports Asynchronously to a new AKAudiofile with trimming options.
///
...
///   - fromSample: start range in samples
///   - toSample: end range time in samples
...
public func exportAsynchronously(name: String,
                                 baseDir: BaseDirectory,
                                 exportFormat: ExportFormat,
                                 fromSample: Int64 = 0,
                                 toSample: Int64 = 0,
                                 callback: @escaping AsyncProcessCallback) {
    let fromFileExt = fileExt.lowercased()

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