Windows Phone 7多声音滞后

Question

I'm making a drum machine. From what I've read, it looks like the XNA SoundEffect class runs based on a timer, which causes a noticeable lag, and stops the rhythm being smooth.

I tried to use MediaElement, 'til I found out you cannot play multiple sounds at the same time.

Are there any workarounds for this? The sounds are handled by a timer, and need to play instantly.

Answer 1

I've done some in-game use of the XNA SoundEffect class and not seen any lag when responding to user events - eg button presses - especially when the sound effect is pre-loaded from resources.

The XNA class is designed to be used for sound effects - so it should be ideal for a single drum machine hit.

If you then see problems with timing on IsLooping, then I guess you'll have to implement your own timer to trigger new instances - but my advice would be to try it first.

Hope that helps

Answer 2

I've been using some sound in my app and I used the code from the example given on the msdn code samples website: http://msdn.microsoft.com/en-us/library/ff431744(v=vs.92).aspx

It looks like they are updating the timer every 50ms. Also note that the SoundEffect variables ( coyoteSound and birdSound ) are private data members where they only load once. The event handler on the button clicks simply call SoundEffect.play() .

public MainPage()
{
    InitializeComponent();

    LoadSound("Resources/NightAmbientCreatureOneShot_01.wav", out coyoteSound);
    LoadSound("Resources/AfternoonAmbientBirdOneShot_09.wav", out birdSound);
    LoadSoundInstance("Resources/NightAmbienceSimple_01.wav", out ambienceSound, out ambienceInstance);

    // Set the volume a little lower than full so it becomes the background.
    ambienceInstance.Volume = 0.8f;

    // Turn on looping so it runs continually in the background.
    ambienceInstance.IsLooped = true;

    // Timer to simulate the XNA game loop (SoundEffect classes are from the XNA Framework)
    DispatcherTimer XnaDispatchTimer = new DispatcherTimer();
    XnaDispatchTimer.Interval = TimeSpan.FromMilliseconds(50);

    // Call FrameworkDispatcher.Update to update the XNA Framework internals.
    XnaDispatchTimer.Tick += delegate { try { FrameworkDispatcher.Update(); } catch { } };

    // Start the DispatchTimer running.
    XnaDispatchTimer.Start();
}