Merge audio files on iPhone

Question

I want to combine the .caf file and the .mp3 file into the .mp3 file on the iPhone, or I can convert them to .aac and then combine them. How can i do this? (Like Kala OK, I want to combine my voice and music together)

Answer 1

You need to decode both files in LPCM (plain old ints), add / mix them together, and then transcode. The iPhone SDK does not support MP3 encoding, so you must transcode to AAC.

Apple's iPhoneExtAudioFileConvertTest sample code would be a good start.

Answer 2

You can use this method

- (BOOL) combineVoices1 { NSError *error = nil; BOOL ok = NO; NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; CMTime nextClipStartTime = kCMTimeZero; //Create AVMutableComposition Object.This object will hold our multiple AVMutableCompositionTrack. AVMutableComposition *composition = [[AVMutableComposition alloc] init]; AVMutableCompositionTrack *compositionAudioTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid]; [compositionAudioTrack setPreferredVolume:0.8]; NSString *soundOne =[[NSBundle mainBundle]pathForResource:@"test1" ofType:@"caf"]; NSURL *url = [NSURL fileURLWithPath:soundOne]; AVAsset *avAsset = [AVURLAsset URLAssetWithURL:url options:nil]; NSArray *tracks = [avAsset tracksWithMediaType:AVMediaTypeAudio]; AVAssetTrack *clipAudioTrack = [[avAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0]; [compositionAudioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, avAsset.duration) ofTrack:clipAudioTrack atTime:kCMTimeZero error:nil]; AVMutableCompositionTrack *compositionAudioTrack1 = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid]; [compositionAudioTrack setPreferredVolume:0.3]; NSString *soundOne1 =[[NSBundle mainBundle]pathForResource:@"test" ofType:@"caf"]; NSURL *url1 = [NSURL fileURLWithPath:soundOne1]; AVAsset *avAsset1 = [AVURLAsset URLAssetWithURL:url1 options:nil]; NSArray *tracks1 = [avAsset1 tracksWithMediaType:AVMediaTypeAudio]; AVAssetTrack *clipAudioTrack1 = [[avAsset1 tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0]; [compositionAudioTrack1 insertTimeRange:CMTimeRangeMake(kCMTimeZero, avAsset.duration) ofTrack:clipAudioTrack1 atTime:kCMTimeZero error:nil]; AVMutableCompositionTrack *compositionAudioTrack2 = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid]; [compositionAudioTrack2 setPreferredVolume:1.0]; NSString *soundOne2 =[[NSBundle mainBundle]pathForResource:@"song" ofType:@"caf"]; NSURL *url2 = [NSURL fileURLWithPath:soundOne2]; AVAsset *avAsset2 = [AVURLAsset URLAssetWithURL:url2 options:nil]; NSArray *tracks2 = [avAsset2 tracksWithMediaType:AVMediaTypeAudio]; AVAssetTrack *clipAudioTrack2 = [[avAsset2 tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0]; [compositionAudioTrack1 insertTimeRange:CMTimeRangeMake(kCMTimeZero, avAsset2.duration) ofTrack:clipAudioTrack2 atTime:kCMTimeZero error:nil]; AVAssetExportSession *exportSession = [AVAssetExportSession exportSessionWithAsset:composition presetName:AVAssetExportPresetAppleM4A]; if (nil == exportSession) return NO; NSString *soundOneNew = [documentsDirectory stringByAppendingPathComponent:@"combined10.m4a"]; //NSLog(@"Output file path - %@",soundOneNew); // configure export session output with all our parameters exportSession.outputURL = [NSURL fileURLWithPath:soundOneNew]; // output path exportSession.outputFileType = AVFileTypeAppleM4A; // output file type // perform the export [exportSession exportAsynchronouslyWithCompletionHandler:^{ if (AVAssetExportSessionStatusCompleted == exportSession.status) { NSLog(@"AVAssetExportSessionStatusCompleted"); } else if (AVAssetExportSessionStatusFailed == exportSession.status) { // a failure may happen because of an event out of your control // for example, an interruption like a phone call comming in // make sure and handle this case appropriately NSLog(@"AVAssetExportSessionStatusFailed"); } else { NSLog(@"Export Session Status: %d", exportSession.status); } }]; return YES; } 

Answer 3

you can use 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"); } 

Answer 4

merging two audio file files

 -(void)mergeTwoAudioFile { NSError * error; NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"Music_Directory"]; //first audio path NSString *firstPath= [documentsDirectory stringByAppendingPathComponent:@"audio01.m4a"]; NSURL *audioUrl1 = [NSURL fileURLWithPath:firstPath]; AVMutableComposition *mixComposition = [AVMutableComposition composition]; AVMutableCompositionTrack *audioCompositionTrack1 =[[AVMutableCompositionTrack alloc]init]; AVURLAsset *audioasset1 = [[AVURLAsset alloc]initWithURL:audioUrl1 options:nil]; AVAssetTrack *audioAssetTrack1= [[audioasset1 tracksWithMediaType:AVMediaTypeAudio] lastObject]; audioCompositionTrack1 = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid]; CMTime tempTime1= mixComposition.duration; [audioCompositionTrack1 insertTimeRange:CMTimeRangeMake(kCMTimeZero, audioasset1.duration) ofTrack:audioAssetTrack1 atTime:tempTime1 error:&error]; //========second audio NSString *secondPath= [documentsDirectory stringByAppendingPathComponent:@"audio02.m4a"]; NSURL *audioUrl2 = [NSURL fileURLWithPath:secondPath]; AVMutableCompositionTrack *audioCompositionTrack2 =[[AVMutableCompositionTrack alloc]init]; AVURLAsset *audioasset2 = [[AVURLAsset alloc]initWithURL:audioUrl2 options:nil]; AVAssetTrack *audioAssetTrack2= [[audioasset2 tracksWithMediaType:AVMediaTypeAudio] lastObject]; audioCompositionTrack2 = [mixComposition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid]; CMTime tempTime2 = mixComposition.duration; [audioCompositionTrack2 insertTimeRange:CMTimeRangeMake(kCMTimeZero, audioasset2.duration) ofTrack:audioAssetTrack2 atTime:tempTime2 error:&error]; NSString * pathToSave = [NSString stringWithFormat:@"finalTest.m4a"]; pathToSave =[documentsDirectory stringByAppendingPathComponent:pathToSave]; NSURL *movieUrl = [NSURL fileURLWithPath:pathToSave]; AVAssetExportSession *exporter =[[AVAssetExportSession alloc] initWithAsset:mixComposition presetName:AVAssetExportPresetAppleM4A]; exporter.shouldOptimizeForNetworkUse = YES; exporter.outputURL = movieUrl; exporter.outputFileType = AVFileTypeAppleM4A; //==================================================================== float audioStartTime=0; CMTime assetTime1 = [audioasset1 duration]; Float64 duration1 = CMTimeGetSeconds(assetTime1); CMTime assetTime2 = [audioasset2 duration]; Float64 duration2 = CMTimeGetSeconds(assetTime2); float audioEndTime=duration1+duration2; CMTime startTime = CMTimeMake((int)(floor(audioStartTime * 100)), 100); CMTime stopTime = CMTimeMake((int)(ceil(audioEndTime * 100)), 100); CMTimeRange exportTimeRange = CMTimeRangeFromTimeToTime(startTime, stopTime); exporter.timeRange =exportTimeRange; //==================================================================== [exporter exportAsynchronouslyWithCompletionHandler:^(void) { NSString* message; switch (exporter.status) { case AVAssetExportSessionStatusFailed: message = [NSString stringWithFormat:@"Export failed. Error: %@", exporter.error.description]; NSLog(@"%@", message); break; case AVAssetExportSessionStatusCompleted: message = [NSString stringWithFormat:@"Export completed"]; NSLog(@"%@", message); break; case AVAssetExportSessionStatusCancelled: message = [NSString stringWithFormat:@"Export cancelled!"]; NSLog(@"%@", message); break; default: NSLog(@"Export unhandled status: %ld", (long)exporter.status); break; } }]; }