вы можете использовать эту SDAVAssetExportSession со следующим кодом для экспорта многих файлов в 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");
}