Seemingly random file corruption using AVAudioRecorder (Sometimes the file can't be played back) - iOS

In an app I'm currently developing, I've more or less hit a brick wall. In the application you can enter a view which lists all locally saved audio files in a standard table view. From here you can click on them to play them, or hit a record button below to make a new recording, which will afterwards automatically get saved to the apps sandbox.

Now all of this actually works perfectly fine, most of the time. I can sit and make recordings and play them back. I can sit and test this on and on for around 45 with no problems whatsoever. Then suddenly at random times I will hit a very odd problem. The problem is that the recorder all of the sudden starts to save nothing but corrupt files which can't be played back and are exactly 4096 bytes in size, no matter how long you recorder for.

I use the AVAudioRecorder in a totally standard fashion, setting it up like this:

// Specific settings for the audio recording
NSDictionary *recordSettings = [NSDictionary dictionaryWithObjectsAndKeys:
    [NSNumber numberWithInt:AVAudioQualityMin],
    AVEncoderAudioQualityKey,
    [NSNumber numberWithInt:8], 
    AVEncoderBitRateKey,
    [NSNumber numberWithInt: 2], 
    AVNumberOfChannelsKey,
    [NSNumber numberWithFloat:22000.0], 
    AVSampleRateKey,
    nil];

NSError *error = nil;
audioRecorder = [[AVAudioRecorder alloc]
    initWithURL:contentURL
    settings:recordSettings
    error:&error];
audioRecorder.delegate = self;

I start the recording like this:

if (!isRecording) {
    isRecording = YES;
    [audioRecorder record];

    // Start the timer
    recordTiming = [NSDate date];

    timeCheck = [NSTimer
        scheduledTimerWithTimeInterval:1.0f
        target:self
        selector:@selector(timeCheck)
        userInfo:nil
        repeats:YES];
}

And then stopping it with this:

if (isRecording) {
    [audioRecorder stop];

    // Stop the timer
    [timeCheck invalidate]


                    
                    
                        
                        ios
                        
                        audio
                        
                        audio-recording
                        
                        avaudiorecorder
                        
                        corrupt
                        
                    
                    
                        
                        
                        
                        
                        
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Note: Since the OP is inactive for some days and I guess this question should be answered for public's future reference, thus I post this answer.

The AVAudioSession has to be obtained before start recording.

AVAudioSession *audioSession = [AVAudioSession sharedInstance];
NSError *err = nil;
[audioSession setCategory :AVAudioSessionCategoryPlayAndRecord error:&err];
if(err){
   NSLog(@"audioSession: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
   return;
}
err = nil;
[audioSession setActive:YES error:&err];
if(err){
   NSLog(@"audioSession: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
   return;
}

Reference: https://stackoverflow.com/a/9706731/188331

answered 2013-03-08T07:28:12.217

Seemingly random file corruption using AVAudioRecorder (Sometimes the file can't be played back) - iOS

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