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Playing a paused AVAudioRecorder file

in my program, I want the user to be able to:

  • record your voice
  • pause the recording process,
  • listen to what he recorded.
  • and then continue recording.

I managed to get to the point where I can record and play back recordings using AVAudioRecorder and AVAudioPlayer. But whenever I try to record, pause the recording and then play, the game part crashes without errors.

I can guess that the reason it is not playing is because the audio file has not yet been saved and is still in memory or something like that.

Is there a way to play paused recordings? If there is, please tell me how

I am using xcode 4.3.2

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RecordAudioViewController.h

#import <UIKit/UIKit.h> #import <AVFoundation/AVFoundation.h> #import <CoreAudio/CoreAudioTypes.h> @interface record_audio_testViewController : UIViewController <AVAudioRecorderDelegate> { IBOutlet UIButton * btnStart; IBOutlet UIButton * btnPlay; IBOutlet UIActivityIndicatorView * actSpinner; BOOL toggle; //Variables setup for access in the class: NSURL * recordedTmpFile; AVAudioRecorder * recorder; NSError * error; } @property (nonatomic,retain)IBOutlet UIActivityIndicatorView * actSpinner; @property (nonatomic,retain)IBOutlet UIButton * btnStart; @property (nonatomic,retain)IBOutlet UIButton * btnPlay; - (IBAction) start_button_pressed; - (IBAction) play_button_pressed; @end

RecordAudioViewController.m

  @synthesize actSpinner, btnStart, btnPlay; - (void)viewDidLoad { [super viewDidLoad]; //Start the toggle in true mode. toggle = YES; btnPlay.hidden = YES; //Instanciate an instance of the AVAudioSession object. AVAudioSession * audioSession = [AVAudioSession sharedInstance]; //Setup the audioSession for playback and record. //We could just use record and then switch it to playback leter, but //since we are going to do both lets set it up once. [audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error: &error]; //Activate the session [audioSession setActive:YES error: &error]; } - (IBAction) start_button_pressed{ if(toggle) { toggle = NO; [actSpinner startAnimating]; [btnStart setTitle:@"Stop Recording" forState: UIControlStateNormal ]; btnPlay.enabled = toggle; btnPlay.hidden = !toggle; //Begin the recording session. //Error handling removed. Please add to your own code. //Setup the dictionary object with all the recording settings that this //Recording sessoin will use //Its not clear to me which of these are required and which are the bare minimum. //This is a good resource: http://www.totodotnet.net/tag/avaudiorecorder/ NSMutableDictionary* recordSetting = [[NSMutableDictionary alloc] init]; [recordSetting setValue :[NSNumber numberWithInt:kAudioFormatAppleIMA4] forKey:AVFormatIDKey]; [recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey]; [recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey]; //Now that we have our settings we are going to instanciate an instance of our recorder instance. //Generate a temp file for use by the recording. //This sample was one I found online and seems to be a good choice for making a tmp file that //will not overwrite an existing one. //I know this is a mess of collapsed things into 1 call. I can break it out if need be. recordedTmpFile = [NSURL fileURLWithPath:[NSTemporaryDirectory() stringByAppendingPathComponent: [NSString stringWithFormat: @"%.0f.%@", [NSDate timeIntervalSinceReferenceDate] * 1000.0, @"caf"]]]; NSLog(@"Using File called: %@",recordedTmpFile); //Setup the recorder to use this file and record to it. recorder = [[ AVAudioRecorder alloc] initWithURL:recordedTmpFile settings:recordSetting error:&error]; //Use the recorder to start the recording. //Im not sure why we set the delegate to self yet. //Found this in antother example, but Im fuzzy on this still. [recorder setDelegate:self]; //We call this to start the recording process and initialize //the subsstems so that when we actually say "record" it starts right away. [recorder prepareToRecord]; //Start the actual Recording [recorder record]; //There is an optional method for doing the recording for a limited time see //[recorder recordForDuration:(NSTimeInterval) 10] } else { toggle = YES; [actSpinner stopAnimating]; [btnStart setTitle:@"Start Recording" forState:UIControlStateNormal ]; btnPlay.enabled = toggle; btnPlay.hidden = !toggle; NSLog(@"Using File called: %@",recordedTmpFile); //Stop the recorder. [recorder stop]; } } - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; // Release any cached data, images, etc that aren't in use. } -(IBAction) play_button_pressed{ //The play button was pressed... //Setup the AVAudioPlayer to play the file that we just recorded. AVAudioPlayer * avPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:recordedTmpFile error:&error]; [avPlayer prepareToPlay]; [avPlayer play]; } - (void)viewDidUnload { // Release any retained subviews of the main view. // eg self.myOutlet = nil; //Clean up the temp file. NSFileManager * fm = [NSFileManager defaultManager]; [fm removeItemAtPath:[recordedTmpFile path] error:&error]; //Call the dealloc on the remaining objects. [recorder dealloc]; recorder = nil; recordedTmpFile = nil; } - (void)dealloc { [super dealloc]; } @end

RecordAudioViewController.xib

take 2 buttons. 1 to start recording, and another to record playback

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If you want to play the recording, then yes, you must stop recording before you can load the file into an AVAudioPlayer instance.

If you want to play a recording, then add more to the recording after listening to it or say the recording in the middle. Then you have some problems.

You need to create a new audio file and then merge them.

This was my solution:

 // Generate a composition of the two audio assets that will be combined into // a single track AVMutableComposition* composition = [AVMutableComposition composition]; AVMutableCompositionTrack* audioTrack = [composition addMutableTrackWithMediaType:AVMediaTypeAudio preferredTrackID:kCMPersistentTrackID_Invalid]; // grab the two audio assets as AVURLAssets according to the file paths AVURLAsset* masterAsset = [[AVURLAsset alloc] initWithURL:[NSURL fileURLWithPath:self.masterFile] options:nil]; AVURLAsset* activeAsset = [[AVURLAsset alloc] initWithURL:[NSURL fileURLWithPath:self.newRecording] options:nil]; NSError* error = nil; // grab the portion of interest from the master asset [audioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, masterAsset.duration) ofTrack:[[masterAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:kCMTimeZero error:&error]; if (error) { // report the error return; } // append the entirety of the active recording [audioTrack insertTimeRange:CMTimeRangeMake(kCMTimeZero, activeAsset.duration) ofTrack:[[activeAsset tracksWithMediaType:AVMediaTypeAudio] objectAtIndex:0] atTime:masterAsset.duration error:&error]; if (error) { // report the error return; } // now export the two files // create the export session // no need for a retain here, the session will be retained by the // completion handler since it is referenced there AVAssetExportSession* exportSession = [AVAssetExportSession exportSessionWithAsset:composition presetName:AVAssetExportPresetAppleM4A]; if (nil == exportSession) { // report the error return; } NSString* combined = @"combined file path";// create a new file for the combined file // configure export session output with all our parameters exportSession.outputURL = [NSURL fileURLWithPath:combined]; // output path exportSession.outputFileType = AVFileTypeAppleM4A; // output file type [exportSession exportAsynchronouslyWithCompletionHandler:^{ // export status changed, check to see if it done, errored, waiting, etc switch (exportSession.status) { case AVAssetExportSessionStatusFailed: break; case AVAssetExportSessionStatusCompleted: break; case AVAssetExportSessionStatusWaiting: break; default: break; } NSError* error = nil; // your code for dealing with the now combined file }];

I cannot take full responsibility for this work, but it was assembled along with the introduction of several others:

AVAudioRecorder / AVAudioPlayer - add an entry to the file

(I can not find another link at the moment)

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