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Problem with AVAudioRecorder metering

User Post

2:19 am
June 28, 2009



posts 1


Hi Everyone,

I am totally desperate now with this new class. I managed to make it work and record audio without problems but for some reason the metering does not work.

Could you please give me some help with this, what am I doing wrong:

In this very simple example I just want to display the current peak or average level, but I always get 0 or -160.

some code:

[[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryPlayAndRecord error: nil];

        NSDictionary *recordSettings =

[[NSDictionary alloc] initWithObjectsAndKeys:

[NSNumber numberWithFloat: 44100.0],                 AVSampleRateKey,

[NSNumber numberWithInt: kAudioFormatAppleLossless], AVFormatIDKey,

[NSNumber numberWithInt: 1],                         AVNumberOfChannelsKey,

[NSNumber numberWithInt: AVAudioQualityMax],         AVEncoderAudioQualityKey,


        soundRecorder = [[AVAudioRecorder alloc] initWithURL: recURL

                                                                   settings: recordSettings

                                                                      error: nil];

soundRecorder.meteringEnabled = TRUE;

        soundRecorder.delegate = self;

        [soundRecorder prepareToRecord];

        [soundRecorder record];

and I have a timer for checking:

[soundRecorder updateMeters];

for (int k=0; k < 3; k++) {

float peak = [soundRecorder peakPowerForChannel:k];

float average = [soundRecorder averagePowerForChannel:k];

NSLog(@”Peak power for channel %i: %4.2f”,k,peak);

NSLog(@”Average power for channel %i: %4.2f”,k,average);


I am not sure with the channels, 0 and 1 gives always 0, all the other gives -160

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