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我在 OpenAL 框架上遇到了困难……我只想改变播放动作的音调……我的项目中缺少什么代码……我是目标 c、iOS 开发的新手。希望得到您的善意考虑，在此先感谢..这是我的三个按钮（记录，停止，播放）的代码..

-(void)startRecording:(UIButton *)sender
{   //for recording

    recStopBtn.hidden = NO;
    recStopBtn.enabled =YES;
    playRecBtn.enabled = NO;
    loading.hidden = NO;
    [loading startAnimating];

    AVAudioSession *audioSession = [AVAudioSession sharedInstance];
    NSError *err = nil;
    [audioSession setCategory :AVAudioSessionCategoryPlayAndRecord error:&err];
    if(err)
    {
        NSLog(@"audioSession: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
        return;
    }
    [audioSession setActive:YES error:&err];
    err = nil;
    if(err)
    {
        NSLog(@"audioSession: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
        return;
    }

    recordSetting = [[NSMutableDictionary alloc] init];

    // We can use kAudioFormatAppleIMA4 (4:1 compression) or kAudioFormatLinearPCM for nocompression
    [recordSetting setValue :[NSNumber numberWithInt:kAudioFormatAppleIMA4] forKey:AVFormatIDKey];

    // We can use 44100, 32000, 24000, 16000 or 12000 depending on sound quality
    [recordSetting setValue:[NSNumber numberWithFloat:16000.0] forKey:AVSampleRateKey];

    // We can use 2(if using additional h/w) or 1 (iPhone only has one microphone)
    [recordSetting setValue:[NSNumber numberWithInt: 1] forKey:AVNumberOfChannelsKey];

    // These settings are used if we are using kAudioFormatLinearPCM format
    //[recordSetting setValue :[NSNumber numberWithInt:16] forKey:AVLinearPCMBitDepthKey];
    //[recordSetting setValue :[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsBigEndianKey];
    //[recordSetting setValue :[NSNumber numberWithBool:NO] forKey:AVLinearPCMIsFloatKey];

    recorderFilePath = [NSString stringWithFormat:@"%@/MySound.caf", DOCUMENTS_FOLDER];



    NSLog(@"recorderFilePath: %@",recorderFilePath);

    NSURL *url = [NSURL fileURLWithPath:recorderFilePath];

    err = nil;

    NSData *audioData = [NSData dataWithContentsOfFile:[url path] options: 0 error:&err];
    if(audioData)
    {
        NSFileManager *fm = [NSFileManager defaultManager];
        [fm removeItemAtPath:[url path] error:&err];
    }

    err = nil;
    recorder = [[ AVAudioRecorder alloc] initWithURL:url settings:recordSetting error:&err];
    if(!recorder){
        NSLog(@"recorder: %@ %d %@", [err domain], [err code], [[err userInfo] description]);
        UIAlertView *alert =
        [[UIAlertView alloc] initWithTitle: @"Warning"
                                   message: [err localizedDescription]
                                  delegate: nil
                         cancelButtonTitle:@"OK"
                         otherButtonTitles:nil];
        [alert show];

        return;
    }

    //prepare to record
    [recorder setDelegate:self];
    [recorder prepareToRecord];
    recorder.meteringEnabled = YES;

    BOOL audioHWAvailable = audioSession.inputIsAvailable;
    if (! audioHWAvailable) {
        UIAlertView *cantRecordAlert =
        [[UIAlertView alloc] initWithTitle: @"Warning"
                                   message: @"Audio input hardware not available"
                                  delegate: nil
                         cancelButtonTitle:@"OK"
                         otherButtonTitles:nil];
        [cantRecordAlert show];

        return;
    }

    // start recording
    [recorder record];

    lblStatusMsg.text = @"Recording...";
    //recIcon.image = [UIImage imageNamed:@"rec_icon.png"];
    //progressView.progress = 0.0;
    //timer = [NSTimer scheduledTimerWithTimeInterval:6.0 target:self selector:@selector(handleTimer) userInfo:nil repeats:YES];
}

-(void)stopRecord:(UIButton *)sender
{
    loading.hidden = YES;
    [loading stopAnimating];

    recStartBtn.enabled = YES;
    recStartBtn.hidden = NO;
    playRecBtn.hidden = NO;

    playRecBtn.enabled = YES;
    recStopBtn.enabled = NO;
    recStopBtn.hidden = YES;
    [recorder stop];

    [timer invalidate];
    lblStatusMsg.text = @"Stopped";
    // recIcon.image = [UIImage imageNamed:@"rec_icon2.png"];

}

-(void)playRecord:(UIButton *)sender
{
    recorderFilePath = [NSString stringWithFormat:@"%@/MySound.caf", DOCUMENTS_FOLDER];
    NSURL *urlRecord = [NSURL fileURLWithPath:recorderFilePath isDirectory:NO];
    NSError *errorRecord;
    soundRecord = [[AVAudioPlayer alloc] initWithContentsOfURL:urlRecord error:&errorRecord];
    [soundRecord play];
}


-(void)changePitch:(UIButton *)sender
{


    alSourcef(recorderFilePath, AL_PITCH, 1.2f);//this kinda troubles me,the source. =(
    [soundRecord play];//this one also...

}
4

1 回答 1

0

alSourcef 方法的第一个参数不是 NSString 文件路径，它是表示音频源的 ALuint。

有关如何从 URL 设置 OpenAL 源的信息，请参阅示例oalTouch （特别是 oalPlayback 类）。

于 2012-07-19T16:35:47.197 回答