Record audio and save permanently in iOS

Question

I have made 2 iPhone apps which can record audio and save it to a file and play it back again.

One of them uses AVAudiorecorder and AVAudioplayer. The second one is

Answer 1

Ok I finally solved it. The problem was that I was setting up the AVAudioRecorder and file the path in the viewLoad of my ViewController.m overwriting existing files with the same name.

1. After recording and saving the audio to file and stopping the app, I could find the file in Finder. (/Users/xxxxx/Library/Application Support/iPhone Simulator/6.0/Applications/0F107E80-27E3-4F7C-AB07-9465B575EDAB/Documents/sound1.caf)

2. When I restarted the application the setup code for the recorder (from viewLoad) would just overwrite my old file called:

   sound1.caf

3. with a new one. Same name but no content.

4. The play back would just play an empty new file. --> No Sound obviously.

---

So here is what I did:

I used NSUserdefaults to save the path of the recorded file name to be retrieved later in my playBack method.

---

cleaned viewLoad in ViewController.m :

- (void)viewDidLoad
{

     AVAudioSession *audioSession = [AVAudioSession sharedInstance];

     [audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:nil];

     [audioSession setActive:YES error:nil];

     [recorder setDelegate:self];

     [super viewDidLoad];
}

edited record in ViewController.m :

- (IBAction) record
{

    NSError *error;

    // Recording settings
    NSMutableDictionary *settings = [NSMutableDictionary dictionary];

    [settings setValue: [NSNumber numberWithInt:kAudioFormatLinearPCM] forKey:AVFormatIDKey];
    [settings setValue: [NSNumber numberWithFloat:8000.0] forKey:AVSampleRateKey];
    [settings setValue: [NSNumber numberWithInt: 1] forKey:AVNumberOfChannelsKey];
    [settings setValue: [NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];
    [settings setValue: [NSNumber numberWithBool:NO] forKey:AVLinearPCMIsBigEndianKey];
    [settings setValue: [NSNumber numberWithBool:NO] forKey:AVLinearPCMIsFloatKey];
    [settings setValue:  [NSNumber numberWithInt: AVAudioQualityMax] forKey:AVEncoderAudioQualityKey];

    NSArray *searchPaths =NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentPath_ = [searchPaths objectAtIndex: 0];

    NSString *pathToSave = [documentPath_ stringByAppendingPathComponent:[self dateString]];

    // File URL
    NSURL *url = [NSURL fileURLWithPath:pathToSave];//FILEPATH];


    //Save recording path to preferences
    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];


    [prefs setURL:url forKey:@"Test1"];
    [prefs synchronize];


    // Create recorder
    recorder = [[AVAudioRecorder alloc] initWithURL:url settings:settings error:&error];

    [recorder prepareToRecord];

    [recorder record];
}

edited playback in ViewController.m:

-(IBAction)playBack
{

AVAudioSession *audioSession = [AVAudioSession sharedInstance];

[audioSession setCategory:AVAudioSessionCategoryPlayback error:nil];

[audioSession setActive:YES error:nil];


//Load recording path from preferences
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];


temporaryRecFile = [prefs URLForKey:@"Test1"];



player = [[AVAudioPlayer alloc] initWithContentsOfURL:temporaryRecFile error:nil];



player.delegate = self;


[player setNumberOfLoops:0];
player.volume = 1;


[player prepareToPlay];

[player play];


}

and added a new dateString method to ViewController.m:

- (NSString *) dateString
{
    // return a formatted string for a file name
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    formatter.dateFormat = @"ddMMMYY_hhmmssa";
    return [[formatter stringFromDate:[NSDate date]] stringByAppendingString:@".aif"];
}

---

Now it can load the last recorded file via NSUserdefaults loading it with:

    //Load recording path from preferences
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];


temporaryRecFile = [prefs URLForKey:@"Test1"];



player = [[AVAudioPlayer alloc] initWithContentsOfURL:temporaryRecFile error:nil];

in (IBAction)playBack. temporaryRecFile is a NSURL variable in my ViewController class.

declared as following ViewController.h :

@interface SoundRecViewController : UIViewController <AVAudioSessionDelegate,AVAudioRecorderDelegate, AVAudioPlayerDelegate>
{
......
......
    NSURL *temporaryRecFile;

    AVAudioRecorder *recorder;
    AVAudioPlayer *player;

}
......
......
@end