使用SoundEffect同时播放音频片段时出现滞后

Question

我正在开发一个Windows Phone应用程序，遇到了以下问题。我有一个循环的.Wav文件的背景音乐，可以切换或关闭。按下按钮即可播放额外的音效(如Sound1)。当背景音乐关闭时，音效可以正常播放。然而，当背景音乐打开时，按下按钮和声音效果之间有一个轻微的(但非常明显的)延迟。有什么我可以通过编程来避免这种情况的吗？根据MSDN网站http://msdn.microsoft.com/en-us/library/ff431744%28v=vs.92%29.aspx上的建议，我设置了一个dispatcherTimer来每隔50ms调用FrameworkDispatcher.Update一次。然而，这似乎没有太大的帮助...我已经粘贴了下面的一些代码。我还能做些什么来摆脱这种延迟呢？

public partial class Modules : PhoneApplicationPage
{
    static SoundEffectInstance loopedSound = null;
    static SoundEffectInstance sound1=null;
    double pitchValue = 4.0;
    static double pitchAdjust = 0.0;

    public Modules()
    {
        InitializeComponent();

        // Timer to simulate the XNA game loop (SoundEffect classes are from the XNA Framework)
        DispatcherTimer XnaDispatchTimer = new DispatcherTimer();
        XnaDispatchTimer.Interval = TimeSpan.FromMilliseconds(50);
        XnaDispatchTimer.Tick += delegate { try { FrameworkDispatcher.Update(); } catch { } };
        XnaDispatchTimer.Start();
    }



    private void playButton_Click(object sender, RoutedEventArgs e)
    {
        if (loopedSound!=null) 
            loopedSound.Dispose();
        SoundEffect sound = SoundEffect.FromStream(Application.GetResourceStream(new Uri(@"BackgroundSound.wav", UriKind.Relative)).Stream);
        LoopClip(sound);

    }

    private void stopButton_Click(object sender, RoutedEventArgs e)
    {
        loopedSound.Stop();
    }

    static protected void LoopClip(SoundEffect soundEffect)
    {
        loopedSound = soundEffect.CreateInstance();
        loopedSound.IsLooped = true;
        loopedSound.Pitch = (float) pitchAdjust;
        loopedSound.Play();
    }

    static protected void sound1Clip(SoundEffect soundEffect)
    {
        sound1 = soundEffect.CreateInstance();
        sound1.IsLooped = false;
        sound1.Play();
    }


    private void Sound1Button_Click(object sender, RoutedEventArgs e)
    {
        if (sound1 == null)
        {
            SoundEffect sound =    SoundEffect.FromStream(Application.GetResourceStream(new Uri(@"sound1.wav", UriKind.Relative)).Stream);
            sound1Clip(sound);
        }
        if (sound1 != null)
        {

            sound1.Play();
        }


    }



}

}

Answer 1

预先加载SoundEffect，这样就不会从FromStream()得到延迟。然而，这对手机来说并不是很友好。