Question

The Problem

I’m trying to play a short (4 second) audio clip in an iOS app.

• On the device (an iPhone 3G with iOS 4.2.1) I get silence. However, the vibrate does trigger as needed.
• In the simulator, the audio plays as expected.

I’m running in a Lion VM instance 10.7.2 on VMWare on top of Snow Leopard 10.6.8.

What I’ve tried

• Checking the format – it’s a linear PCM file
• Converting the file to a 16 bit audio file (Audacity reckoned it was 32 bit)
• Made sure the case of the filename is identical between code and files.
• Cleaned the target, deleted it from iPhone and rebuilt.

Code

    // Usage from class
    -(void)loadRunningView {
        JGTimerRunningViewController *runningViewController = [[JGTimerRunningViewController alloc] initWithNibName:@"JGRunningViewController" bundle:nil];
        [runningViewController loadAlertSoundWithFilename:@"DigitalAlarm1"];
    }

    @interface JGTimerRunningViewController : UIViewController {
        IBOutlet UILabel *timeLabel;
        CFURLRef soundFileURLRef;
        SystemSoundID soundFileObject;
    }

    @implementation JGTimerRunningViewController

    -(void)loadAlertSoundWithFilename:(NSString *)alertSoundFilename_ {
        // Get the main bundle for the app
        CFBundleRef mainBundle = CFBundleGetMainBundle ();
        CFStringRef filename = (CFStringRef)alertSoundFilename_;
        soundFileURLRef = CFBundleCopyResourceURL (mainBundle, filename, CFSTR ("aiff"), NULL);
        // Create a system sound object representing the sound file
        AudioServicesCreateSystemSoundID (soundFileURLRef, &soundFileObject);
    }
    ..
    -(IBAction)playSound:(id)sender {
        AudioServicesPlaySystemSound (soundFileObject);
        AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);
    }

    -(void)showRedCard {
        [[self view] setBackgroundColor:[UIColor redColor]];
        [self playSound:self];
    }
    ...
    - (void)dealloc {
        CFRelease(soundFileURLRef);
        AudioServicesDisposeSystemSoundID(soundFileObject);
        [timeLabel release];
        [super dealloc];
    }
    @end

Answer 1

It turns out that somehow I had the volume turned down on the iPhone!