Question

我一直在研究Apple的Aurio Touch示例代码。我想知道如何使用它来测量像风速计那样的风速。有什么建议吗？麦克风对声音做出反应，吹入麦克风的空气确实可以测量声音。如何实现这个来测量风速？有人可以帮我这个吗？

Answer 1

您可以使用AVAudioRecorder执行此操作。

// 1。像这样启动AVAudioRecorder：

    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.delegate = self;
                recorder.meteringEnabled = YES;
                [recorder record];

            }

// 2.初始化计时器以获得平均功率

levelTimer = [NSTimer scheduledTimerWithTimeInterval: 0.03 target: self selector: @selector(levelTimerCallback) userInfo: nil repeats: YES];

-(void)levelTimerCallback
{
    [recorder updateMeters];

    float peak = [recorder averagePowerForChannel:0];
    float value = [meterTable valueAt:peak];
    //meterTable = [[MeterTable alloc] initWithMinDecibels:-80. TableSize:50 Root: 1.3];
    //Value 0.0~1.0 ,
}

您可以从Apple示例avTouch

获取MeterTable

风速应用 - iOS

1 个答案: