iphone - 录制声音并以改变的音高播放

Question

我必须实现一个 iphone 应用程序，它会在您开始说话时录制用户的声音，并改变录制声音的音高并播放它。在 AVAudiorecorder 的帮助下，我能够在检测到声音时录制音频，并且使用 Dirac 库我改变了录制声音的音高。这种方法的问题是输出声音足够嘈杂。我得到了使用 SoundEngine 的响应，但我没有得到实现它的方法。任何人都可以向我解释任何其他实现方法吗？

my code//
        -(void)initialSetup
    { 
        count=0; 
        silenceTime=0;

    //[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord error: nil];
    recordSetting = [[NSMutableDictionary alloc] init];
    [recordSetting setValue:[NSNumber numberWithInt:kAudioFormatAppleLossless] forKey:AVFormatIDKey];
    [recordSetting setValue:[NSNumber numberWithFloat:44100.0] forKey:AVSampleRateKey]; 
    [recordSetting setValue:[NSNumber numberWithInt: 2] forKey:AVNumberOfChannelsKey];
    recordedTmpFile = [NSURL fileURLWithPath:[NSTemporaryDirectory() stringByAppendingPathComponent:[NSString stringWithFormat: @"%.0f.%@",[NSDate timeIntervalSinceReferenceDate]*1000.0,                  @"caf"]]];
    recorder = [[ AVAudioRecorder alloc] initWithURL:recordedTmpFile settings:recordSetting error:&error];
    //recorder = [[ AVAudioRecorder alloc] init];
    [recorder setDelegate:self];
    [recorder updateMeters];
    [recorder prepareToRecord];
    //[[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryPlayAndRecord error: nil];
    //In Order To Move Sound To The Speaker
    //UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_Speaker;
    //AudioSessionSetProperty (kAudioSessionProperty_OverrideAudioRoute,sizeof(audioRouteOverride),&audioRouteOverride);

    NSArray *dirPaths;
    NSString *docsDir;
    dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    docsDir = [dirPaths objectAtIndex:0];
    NSString *soundFilePath = [docsDir stringByAppendingPathComponent:@"audio.caf"];
    recordedTmpFile1 =  [NSURL fileURLWithPath:soundFilePath];

    recordSetting1 =   [[NSMutableDictionary alloc] init];
    recordSetting1 =   [NSDictionary dictionaryWithObjectsAndKeys:
                        [NSNumber numberWithInt:AVAudioQualityMin],AVEncoderAudioQualityKey,
                        //[NSNumber numberWithInt:kAudioFormatAppleIMA4],AVFormatIDKey,
                        [NSNumber numberWithInt:16], 
                        AVEncoderBitRateKey,
                        [NSNumber numberWithInt: 2], 
                        AVNumberOfChannelsKey,
                        [NSNumber numberWithFloat:44100.0], 
                        AVSampleRateKey,nil];
    recorder1 = [[AVAudioRecorder alloc] initWithURL:recordedTmpFile1 settings:recordSetting1 error:&error];
    [recorder1 prepareToRecord];
    [recorder1 setDelegate:self];
    if(recorder) 
    {
        recorder.meteringEnabled = YES;
        [recorder record];
        double val=[recorder peakPowerForChannel:0];
        NSLog(@"The Very First Value Of The Recorder Is=%f",val);
        levelTimer = [NSTimer scheduledTimerWithTimeInterval:0.4 target: self selector: @selector(levelTimerCallback:) userInfo: nil repeats: YES];
    }
    else
    {
        NSLog(@"error in initilising of the recorder=%@",[error localizedDescription]);
    }
}


-(void)levelTimerCallback:(NSTimer *)timer                      
{ 
    [recorder updateMeters];
    const double ALPHA = 0.05;
    //NOISE FILERATION ALGORITHMS
    double peakPowerForChannel = pow(10,(0.05 *[recorder peakPowerForChannel:0]));
    double audioMonitorResults1 = ALPHA * peakPowerForChannel + (1.0 - ALPHA) * audioMonitorResults1;
    double audioMonitorResults;
    audioMonitorResults= [recorder peakPowerForChannel:0];
    NSLog(@"This time only  frequency is==>%f",audioMonitorResults1);
    //if (audioMonitorResults1 >0.020)
    if(audioMonitorResults1 > .05)//the value of audioMonitorResults may be equal to -10 for device
    {

        [recorder1 updateMeters];
        recorder1.meteringEnabled=YES;
        //recorder.meteringEnabled=YES;
        [recorder1 record];
        NSLog(@"SOUND IS DETECTED");
        NSLog(@"%f",[recorder1 peakPowerForChannel:0]);
        NSLog(@"Recording is going on");
        count=1;
        silenceTime=0;

    }
    else
    {

        NSLog(@"NO SOUND IS DETECTED");
        silenceTime=silenceTime+0.3;
        if(count==1 && silenceTime>1)
        { 

            [levelTimer invalidate];
            [recorder1 stop];

        }

    }

}
- (void)audioRecorderDidFinishRecording:(AVAudioRecorder *)recorder successfully:(BOOL)flag
{
    NSLog(@"Recorder stop delegate is processing");
    if(flag)
    {
        NSLog(@"Player has finished successfully");
        [self playRecording];
    }
    else
    { 
        NSLog(@"problem in recording.......not recorded");
    }
}

Answer 1

1. 如何检测声音？
   我在教程的帮助下解决了我的第一个问题..这是链接，链接:http://mobileorchard.com/tutorial-detecting-when-a-user-blows-into-the-mic/
   在这里，我们可以很容易地理解检测到一些噪音时的声音记录。

2. 如何改变录制声音的音高并回放。
   我在改变声音的音高时遇到的第二个问题。因为我们只能在 AVAudioRecorder 的帮助下录制声音，所以我们不能通过它来改变音调。
   为此，我使用了一个外部库 DIRAC。 Here is the link for the Dirac library.
   这带来了一些示例项目(适用于移动应用程序和桌面应用程序)，关于应用程序的狄拉克库的实现。

我发现另一种解决这个问题的方法是通过 Dirac 实现 Cocoas2D、Cocos Denshion。因为上述过程不适用于我的应用程序。 Here is the link for implementing this (关于改变音高和播放录制声音的示例项目)。

我找到了 another link与录音有关。