merge Audio files on iPhone

Question

I wanna merge a .caf file and a .mp3 file to a .mp3 file on iPhone,or I can convert them to .aac and then merge them.How can I do this ? (Just Like Kala OK,I wanna merge

Answer 1

you can use the this SDAVAssetExportSession with the following code to export many files to AAC:

-(void)mergeAudioFiles
{
    NSFileManager * fm = [[NSFileManager alloc] init];
    NSError * error;
    NSArray * filesNames = **NSArray of File Names;
    NSString * filePath = @"Dest File Name";
    NSString * pathToSave =[NSString stringWithFormat:@"%@%@",filePath,@".m4a"];

    CMTime startTime = kCMTimeZero;
    AVMutableComposition *composition = [AVMutableComposition composition];
    AVMutableCompositionTrack *compositionAudioTrack =[AVMutableCompositionTrack alloc];
    compositionAudioTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];

    float audioEndTime=0;
    for (NSString *fileName in filesNames) {
        NSURL *audioUrl = [NSURL fileURLWithPath:fileName];
        AVURLAsset *audioasset = [[AVURLAsset alloc]initWithURL:audioUrl options:nil];
        CMTimeRange timeRange  = CMTimeRangeMake(kCMTimeZero, audioasset.duration);
        AVAssetTrack *audioAssetTrack= [[audioasset tracksWithMediaType:AVMediaTypeAudio] lastObject];
       [compositionAudioTrack insertTimeRange:timeRange ofTrack:audioAssetTrack atTime:startTime error:&error];
       startTime = CMTimeAdd(startTime, timeRange.duration);
       CMTime assetTime2 = [audioasset duration];
       Float64 duration2 = CMTimeGetSeconds(assetTime2);
       audioEndTime+=duration2;
    }

    NSURL *exportUrl = [NSURL fileURLWithPath:pathToSave];

    float audioStartTime=0;
    CMTime startTime1 = CMTimeMake((int)(floor(audioStartTime * 100)), 100);
    CMTime stopTime = CMTimeMake((int)(ceil(audioEndTime * 100)), 100);
    CMTimeRange exportTimeRange = CMTimeRangeFromTimeToTime(startTime1, stopTime);


    SDAVAssetExportSession *encoder = [SDAVAssetExportSession.alloc initWithAsset:composition];
    encoder.outputFileType = AVFileTypeAppleM4A;
    encoder.outputURL = exportUrl;
    encoder.audioSettings = @
    {
       AVFormatIDKey: @(kAudioFormatMPEG4AAC),
       AVNumberOfChannelsKey: @2,
       AVSampleRateKey: @44100,
       AVEncoderBitRateKey: @128000,
    };
    encoder.timeRange = exportTimeRange;
    dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
    NSLog(@"Starting Audio Marge");
   [encoder exportAsynchronouslyWithCompletionHandler:^
   {
        if (encoder.status == AVAssetExportSessionStatusCompleted)
        {
            NSLog(@"Audio Marge succeeded");
            NSError * err = NULL;
            BOOL result = [fm moveItemAtPath:pathToSave toPath:filePath error:&err];
            if(!result) {
                NSLog(@"Error: %@", err);
            }
            NSLog(@"Audio Copied");
        } else if (encoder.status == AVAssetExportSessionStatusCancelled) {
            NSLog(@"Audio export cancelled");
        } else {
           NSLog(@"Audio export failed with error: %@ (%ld)", encoder.error.localizedDescription, encoder.error.code);
        }
        dispatch_semaphore_signal(semaphore);
   }];
   NSLog(@"Audio Wait to Finish");
   dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
  //cleanup
   for (NSString *fileName in filesNames) {
       [fm removeItemAtPath:fileName error:&error];
   }
   NSLog(@"Audio Marge Finished");
}