如何在iPhone应用程序中检测语音？

Question

我想开发一些语音检测方法。

例如，

就像在PragDuck应用程序，当用户开始说话duck开始其动画。

如何检测用户声音？

Answer 1

使用AVAudioRecorder - 音频测量 - 结帐本教程 - dettect当用户吹进麦克风http://mobileorchard.com/tutorial-detecting-when-a-user-blows-into-the-mic/

简单的例子：

_audioRecorder.meteringEnabled = YES;

//1. This method will get the current mic activity and will format it to a 0 - 1 scale. 

-(void)checkRecordingMeters:(NSTimer *)timer 
{ 
     [_audioRecorder updateMeters]; 

     const double ALPHA = 0.2; 
     float peakPower = [_audioRecorder peakPowerForChannel:0]; 

     double peakPowerForChannel = pow(10, (0.05 * peakPower)); 
     lowPassResults = ALPHA * peakPowerForChannel + (1.0 - ALPHA) * lowPassResults; 

     NSLog(@"Meters: %f" , peakPower); 
     NSLog(@"lowPassResults: %f \n" , lowPassResults); 
} 


//2. Call this method to run a loop timer to check the current mic activity 
-(void)enableMettering:(BOOL)enable 
{ 

    if(enable) 
    { 
     levelTimer = [[NSTimer scheduledTimerWithTimeInterval:0.03 
                target:self 
               selector:@selector(checkRecordingMeters:) 
               userInfo:nil 
               repeats:YES] retain]; 
    } 
    else 
    { 
     [levelTimer invalidate]; 
     [levelTimer release]; 
    } 
} 

Answer 2

您可以使用AudioQueue记录并添加一个简单的阈值过滤器来忽略环境噪声。为了降低延迟，您可以使用AudioUnit。