Question

I’ve a bit of code which was working fine with iOS 4.3. I had a look on the Internet, I found others having the same problem without answer which worked for me. I think that I can record something but I cannot play it. Here is my code:

DetailViewController.h

#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
#import <CoreAudio/CoreAudioTypes.h>
#import <AudioToolbox/AudioServices.h>

@interface DetailViewController : UIViewController <UISplitViewControllerDelegate, AVAudioRecorderDelegate> {

id detailItem;
UILabel *detailDescriptionLabel;

IBOutlet UIButton *btnStart;
IBOutlet UIButton *btnPlay;

//Variables setup for access in the class:
NSURL * recordedTmpFile;
AVAudioRecorder * recorder;
BOOL toggle;
}

// Needed properties
@property (nonatomic, retain) IBOutlet UIButton *btnStart;
@property (nonatomic, retain) IBOutlet UIButton *btnPlay;
@property (strong, nonatomic) id detailItem;
@property (strong, nonatomic) IBOutlet UILabel *detailDescriptionLabel;

-(IBAction) start_button_pressed;
-(IBAction) play_button_pressed;
@end

DetailViewController.m

- (void)viewDidLoad {
[super viewDidLoad];
toggle = YES;
btnPlay.hidden = YES;
NSError *error;

// Create the Audio Session
AVAudioSession *audioSession = [AVAudioSession sharedInstance];

// Set up the type of session
[audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:&error];

// Activate the session.
[audioSession setActive:YES error:&error];

[self configureView];    
}

-(IBAction) start_button_pressed{
if (toggle) {
    toggle = NO;
    [btnStart setTitle:@"Press to stop recording" forState:UIControlStateNormal];
    btnPlay.enabled = toggle;
    btnPlay.hidden = !toggle;
            NSError *error;

    NSMutableDictionary *recordSettings = [[NSMutableDictionary alloc] init];

    [recordSettings setValue:[NSNumber numberWithInt:kAudioFormatAppleIMA4] forKey:AVFormatIDKey];

    [recordSettings setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey];

    [recordSettings setValue:[NSNumber numberWithInt:2] forKey:AVNumberOfChannelsKey];

    // Create a temporary files to save the recording. 
    recordedTmpFile = [NSURL fileURLWithPath:[NSTemporaryDirectory() stringByAppendingPathComponent:[NSString stringWithFormat: @"%.0f.%@", [NSDate timeIntervalSinceReferenceDate] * 1000.0, @"caf"]]];

    NSLog(@"The temporary file used is: %@", recordedTmpFile);

    recorder = [[AVAudioRecorder alloc] initWithURL:recordedTmpFile settings:recordSettings error:&error];

    [recorder setDelegate:self];

    [recorder prepareToRecord];
    [recorder record];
}
else {
    toggle = YES;
    [btnStart setTitle:@"Start recording" forState:UIControlStateNormal];
    btnPlay.hidden = !toggle;
    btnPlay.enabled = toggle;

    NSLog(@"Recording stopped and saved in file: %@", recordedTmpFile);
    [recorder stop];
}
}

-(IBAction) play_button_pressed{

NSError *error;
AVAudioPlayer * avPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:recordedTmpFile error:&error];

   if (!error)
   {
       [avPlayer prepareToPlay];
       [avPlayer play];

       NSLog(@"File is playing");
   }

}

- (void) audioPlayerDidFinishPlaying: (AVAudioPlayer *) player
                    successfully: (BOOL) flag {
     NSLog (@"audioPlayerDidFinishPlaying:successfully:");
}

- (void)audioRecorderDidFinishRecording:(AVAudioRecorder *) aRecorder successfully: (BOOL)flag
{
    NSLog (@"audioRecorderDidFinishRecording:successfully:");
}

Here is the of my program running:

2011-11-25 11:58:02.005 Bluetooth1[897:707] The temporary file used is: file://localhost/private/var/mobile/Applications/D81023F8-C53D-4AC4-B1F7-14D66EB4844A/tmp/343915082005.caf
2011-11-25 11:58:05.956 Bluetooth1[897:707] Recording stopped and saved in file: file://localhost/private/var/mobile/Applications/D81023F8-C53D-4AC4-B1F7-14D66EB4844A/tmp/343915082005.caf
2011-11-25 11:58:05.998 Bluetooth1[897:707] audioRecorderDidFinishRecording:successfully:
2011-11-25 11:58:11.785 Bluetooth1[897:707] File is playing

For some reason, the function audioPlayerDidFinishPlaying is never called. However it seems that something has been recorded. Right now I do not know which part is not working but I guess this has something to do with AVAudioPlayer.

[EDIT] It’s getting weirder and weirder. I wanted to make sure that something was recorded so I look for taking the duration of the record. Here is the new play function:

-(IBAction) play_button_pressed{

    NSError *error;
AVAudioPlayer * avPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL: recordedTmpFile error:&error];

    if (!error)
    {
        AVURLAsset* audioAsset = [AVURLAsset URLAssetWithURL:recordedTmpFile options:nil];
        CMTime audioDuration = audioAsset.duration;
        float audioDurationSeconds = CMTimeGetSeconds(audioDuration);

        [avPlayer prepareToPlay];
        [avPlayer play];

        NSString *something = [NSString stringWithFormat:@"%f",audioDurationSeconds]; 
        NSLog(@"File is playing: %@", something);
    }
    else
    {
         NSLog(@"Error playing.");
    }   
}

Now, the length of the record is recorded and it make sense (if I record for 10s it shows something around 10s). However, when I put these lines of code for the first time I forgot to do the conversion float to NSString. So it crashed… and the app play the sound… After different tests I can conclude that my app can record and play a sound but is as to crash to play the recorded sound. I’ve no idea what can be the problem. I found that AVPlayer is asynchronous, is their something to do with that? I’m completely lost…

Answer 1

OK, that is not really cool to answer you own questions. Moreover when the answer is not clean but it is working… In order to play what I have recorded I have used the following block of code:

    AVURLAsset* audioAsset = [AVURLAsset URLAssetWithURL:recordedTmpFile options:nil];
    CMTime audioDuration = audioAsset.duration;
    float audioDurationSeconds = CMTimeGetSeconds(audioDuration);

    [avPlayer prepareToPlay];
    [avPlayer play];

    // Block for audioDurationSeconds seconds
    [NSThread sleepForTimeInterval:audioDurationSeconds];

I am calculating the length of the recorded file and I am waiting for this amount of time… it is dirty but it is doing the trick. Plus, if it launched in another thread it will not block the application.

I anyone has something I would gladly take it!