- (void) setUpAndAddAudioAtPath:(NSURL*)assetURL toComposition:(AVMutableComposition *)composition start:(CMTime)start dura:(CMTime)dura offset:(CMTime)offset{
AVURLAsset *songAsset = [AVURLAsset URLAssetWithURL:assetURL options:nil];
AVMutableCompositionTrack *track = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
AVAssetTrack *sourceAudioTrack = [[songAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0];
NSError *error = nil;
BOOL ok = NO;
CMTime startTime = start;
CMTime trackDuration = dura;
CMTimeRange tRange = CMTimeRangeMake(startTime, trackDuration);
//Set Volume
AVMutableAudioMixInputParameters *trackMix = [AVMutableAudioMixInputParameters audioMixInputParametersWithTrack:track];
[trackMix setVolume:0.8f atTime:startTime];
[audioMixParams addObject:trackMix];
//Insert audio into track //offset CMTimeMake(0, 44100)
ok = [track insertTimeRange:tRange ofTrack:sourceAudioTrack atTime:offset error:&error];
}
- (void) exportAudio {
AVMutableComposition *composition = [AVMutableComposition composition];
audioMixParams = [[NSMutableArray alloc] initWithObjects:nil];
//Add Audio Tracks to Composition
NSString *path = [[NSBundle mainBundle] pathForResource:@"recordedFile" ofType:@"caf"];
NSURL *assetURL1 = [NSURL fileURLWithPath:path];
AVURLAsset *songAsset = [AVURLAsset URLAssetWithURL:assetURL1 options:nil];
CMTime startTime = CMTimeMakeWithSeconds(0, 1);
CMTime trackDuration = songAsset.duration;
[self setUpAndAddAudioAtPath:assetURL1 toComposition:composition start:startTime dura:trackDuration offset:CMTimeMake(14*44100, 44100)];
path = [[NSBundle mainBundle] pathForResource:@"1286" ofType:@"mp3"];
NSURL *assetURL2 = [NSURL fileURLWithPath:path];
[self setUpAndAddAudioAtPath:assetURL2 toComposition:composition start:startTime dura:trackDuration offset:CMTimeMake(0, 44100)];
AVMutableAudioMix *audioMix = [AVMutableAudioMix audioMix];
audioMix.inputParameters = [NSArray arrayWithArray:audioMixParams];
//If you need to query what formats you can export to, here's a way to find out
NSLog (@"compatible presets for songAsset: %@",
[AVAssetExportSession exportPresetsCompatibleWithAsset:composition]);
AVAssetExportSession *exporter = [[AVAssetExportSession alloc]
initWithAsset: composition
presetName: AVAssetExportPresetAppleM4A];
exporter.audioMix = audioMix;
exporter.outputFileType = @"com.apple.m4a-audio";
NSString *fileName = @"someFilename";
NSString *exportFile = [NSHomeDirectory() stringByAppendingFormat: @"/%@.m4a", fileName];
// set up export
if ([[NSFileManager defaultManager] fileExistsAtPath:exportFile]) {
[[NSFileManager defaultManager] removeItemAtPath:exportFile error:nil];
}
NSURL *exportURL = [NSURL fileURLWithPath:exportFile];
exporter.outputURL = exportURL;
// do the export
[exporter exportAsynchronouslyWithCompletionHandler:^{
int exportStatus = exporter.status;
switch (exportStatus) {
case AVAssetExportSessionStatusFailed:{
NSError *exportError = exporter.error;
NSLog (@"AVAssetExportSessionStatusFailed: %@", exportError);
break;
}
case AVAssetExportSessionStatusCompleted: NSLog (@"AVAssetExportSessionStatusCompleted"); break;
case AVAssetExportSessionStatusUnknown: NSLog (@"AVAssetExportSessionStatusUnknown"); break;
case AVAssetExportSessionStatusExporting: NSLog (@"AVAssetExportSessionStatusExporting"); break;
case AVAssetExportSessionStatusCancelled: NSLog (@"AVAssetExportSessionStatusCancelled"); break;
case AVAssetExportSessionStatusWaiting: NSLog (@"AVAssetExportSessionStatusWaiting"); break;
default: NSLog (@"didn't get export status"); break;
}
}];
// // start up the export progress bar
// progressView.hidden = NO;
// progressView.progress = 0.0;
// [NSTimer scheduledTimerWithTimeInterval:0.1
// target:self
// selector:@selector (updateExportProgress:)
// userInfo:exporter
// repeats:YES];
}
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