Question

我正在开发一个应用程序，允许孩子完成呼吸练习作为他们物理治疗过程的一部分，此刻我仍然只是想确认麦克风正在接收吹动的声音。我在NSLog中收到以下消息

2017-04-22 17:01:52.292319+0100 microphone[2251:596932] Mic blow detected
2017-04-22 17:01:52.322377+0100 microphone[2251:596932] Mic blow detected
2017-04-22 17:01:52.352402+0100 microphone[2251:596932] Mic blow detected
2017-04-22 17:01:52.382331+0100 microphone[2251:596932] Mic blow detected
2017-04-22 17:01:52.412318+0100 microphone[2251:596932] Mic blow detected
2017-04-22 17:01:52.442277+0100 microphone[2251:596932] Mic blow detected
2017-04-22 17:01:52.472358+0100 microphone[2251:596932] Mic blow detected
2017-04-22 17:01:52.502275+0100 microphone[2251:596932] Mic blow detected
2017-04-22 17:01:52.532323+0100 microphone[2251:596932] Mic blow detected
2017-04-22 17:01:52.562265+0100 microphone[2251:596932] Mic blow detected
2017-04-22 17:01:52.592255+0100 microphone[2251:596932] Mic blow detected

这是我目前的代码：

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
NSURL *url = [NSURL fileURLWithPath:@"/dev/null"];

NSDictionary *settings = [NSDictionary dictionaryWithObjectsAndKeys:
                          [NSNumber numberWithFloat:44100.0],
                          AVSampleRateKey,
                          [NSNumber numberWithInt: kAudioFormatAppleLossless],
                          AVFormatIDKey,
                          [NSNumber numberWithInt: 1],
                          AVNumberOfChannelsKey,
                          [NSNumber numberWithInt: AVAudioQualityMax],
                          AVEncoderAudioQualityKey, nil];

NSError *error;

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

if (recorder) {
    [recorder prepareToRecord];
    recorder.meteringEnabled = YES;
    [recorder record];
    levelTimer = [NSTimer scheduledTimerWithTimeInterval:0.03 target:self selector:@selector(levelTimerCallBack:) userInfo:nil repeats:YES];
} else
    NSLog(@"%@", [error description]); 
}

- (void)levelTimerCallBack:(NSTimer *)timer {
[recorder updateMeters];

const double ALPHA = 0.05;
double peakPowerForChannel = pow(10, (0.05 * [recorder peakPowerForChannel:0]));
lowPassResults = ALPHA * peakPowerForChannel + (1.0 - ALPHA) * lowPassResults;

if (lowPassResults < 0.000005)
    NSLog(@"Mic blow detected");
}

@end

我最初有“if（lowPassResults＆lt; 0.95）”，但根本没有检测到麦克风。我现在遇到的问题是它没有任何人吹入麦克风时检测到麦克风。我认为值（0.00005）仍然太高但找不到合适的值。任何人都可以建议我需要在这里进行调整吗？

提前致谢

检测麦克风打击

0 个答案: