Get Audio (mp3) From MOV File iOS - ios

Question

How can I extract the Audio (preferably .mp3) from a .MOV file I got from the user's camera roll?
I extract the MOV file here:
- (void) imagePickerController: (UIImagePickerController *) picker
didFinishPickingMediaWithInfo: (NSDictionary *) info {
NSString *mediaType = [info objectForKey: UIImagePickerControllerMediaType];
[self dismissViewControllerAnimated:NO completion:nil];
if (CFStringCompare ((__bridge_retained CFStringRef)mediaType, kUTTypeMovie, 0)
== kCFCompareEqualTo) {
NSString *fileName = [[info objectForKey:
UIImagePickerControllerMediaURL] path];
NSData *data = [[NSData alloc] initWithContentsOfFile:moviePath];
[self dismissViewControllerAnimated:YES completion:nil];
}
}
Please let me know if more code need be provided but I think this is a sufficient amount of information.
I have tried a few things but gotten absolutely nowhere. Any help is appreciated. Thank you

Answer 1

I extract m4a file using the following piece of code and write the file application documents directory
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
AVMutableComposition *newAudioAsset = [AVMutableComposition composition];
AVMutableCompositionTrack *dstCompositionTrack = [newAudioAsset addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid];
// 1 - Get media type
NSString *mediaType = [info objectForKey: UIImagePickerControllerMediaType];
// 2 - Dismiss image picker
[self dismissViewControllerAnimated:YES completion:nil];
// 3 - Handle video selection
if (CFStringCompare ((__bridge_retained CFStringRef) mediaType, kUTTypeMovie, 0) == kCFCompareEqualTo) {
videoAsset = [AVAsset assetWithURL:[info objectForKey:UIImagePickerControllerMediaURL]];
// NSLog(#"track = %#",[videoAsset tracksWithMediaType:AVMediaTypeAudio]);
NSArray *trackArray = [videoAsset tracksWithMediaType:AVMediaTypeAudio];
if(!trackArray.count){
NSLog(#"Track returns empty array for mediatype AVMediaTypeAudio");
return;
}
AVAssetTrack *srcAssetTrack = [trackArray objectAtIndex:0];
//Extract time range
CMTimeRange timeRange = srcAssetTrack.timeRange;
NSError *err = nil;
if(NO == [dstCompositionTrack insertTimeRange:timeRange ofTrack:srcAssetTrack atTime:kCMTimeZero error:&err]){
NSLog(#"Failed to insert audio from the video to mutable avcomposition track");
return;
}
//Export the avcompostion track to destination path
NSString *documentsDirectory = [NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex: 0];
NSString *dstPath = [documentsDirectory stringByAppendingString:#"/sample_audio.m4a"];
NSURL *dstURL = [NSURL fileURLWithPath:dstPath];
//Remove if any file already exists
[[NSFileManager defaultManager] removeItemAtURL:dstURL error:nil];
AVAssetExportSession *exportSession = [[AVAssetExportSession alloc]initWithAsset:newAudioAsset presetName:AVAssetExportPresetPassthrough];
NSLog(#"support file types= %#", [exportSession supportedFileTypes]);
exportSession.outputFileType = AVFileTypeAppleM4A;
exportSession.outputURL = dstURL;
[exportSession exportAsynchronouslyWithCompletionHandler:^{
AVAssetExportSessionStatus status = exportSession.status;
if(AVAssetExportSessionStatusCompleted != status){
NSLog(#"Export status not yet completed. Error: %#", exportSession.error.description);
}
}];
// UIAlertView *alert = [[UIAlertView alloc] initWithTitle:#"Asset Loaded" message:#"Video Asset Loaded"
// delegate:nil cancelButtonTitle:#"OK" otherButtonTitles:nil];
// [alert show];
}
}