混合时AVAudioPlayer声音文件播放不同步 - iPhone

Question

我正在尝试使用AVAudioPlayer的实例播放6个单独的.mp3声音文件.声音同时播放,但它们似乎播放不同步或速度略有不同.有谁知道为什么会这样？

以下是我初始化声音的方法:

 NSURL *musicurl = [[NSURL alloc] initFileURLWithPath:[[NSBundle mainBundle] pathForResource: @"SoundLoop" ofType: @"mp3"]];
music = [[AVAudioPlayer alloc] initWithContentsOfURL: musicurl error: nil];
[musicurl release];
music.numberOfLoops = -1; // Loop indefinately
music.currentTime = 0; // start at beginning
music.volume = 1.0;
music.meteringEnabled = YES;

这是我的AudioSession代码:

AVAudioSession *audioSession = [AVAudioSession sharedInstance];
audioSession.delegate = self;
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayback error:nil];     
[[AVAudioSession sharedInstance] setPreferredHardwareSampleRate:44100 error:nil];
[[AVAudioSession sharedInstance] setPreferredIOBufferDuration:30 error:nil];

UInt32 sessionCategory = kAudioSessionCategory_MediaPlayback;
Float32 hardvol = 1.0;
AudioSessionSetProperty(kAudioSessionProperty_AudioCategory, sizeof(sessionCategory), &sessionCategory);
AudioSessionSetProperty(kAudioSessionProperty_CurrentHardwareOutputVolume, sizeof(hardvol), &hardvol);
UInt32 doSetProperty = 1;
AudioSessionSetProperty(kAudioSessionProperty_OverrideCategoryMixWithOthers, sizeof(doSetProperty), &doSetProperty);
[[AVAudioSession sharedInstance] setActive:YES error: nil]; 

它可能与声音的比特率有关吗？或者我正在使用.mp3？

谢谢.

Answer 1

我通过使用AVAudioPlayer类的playAtTime:方法找到了解决此问题的方法:

   NSTimeInterval shortStartDelay = 0.5;            // seconds
    NSTimeInterval now = player.deviceCurrentTime;

    [player playAtTime:now + shortStartDelay];  //these players are instances of AVAudioPlayer
    [player2 playAtTime:now + shortStartDelay];
    [player3 playAtTime:now + shortStartDelay];

使用它将允许所有声音异步和同步播放.