Package	flash.events
Class	public class SampleDataEvent
Inheritance	SampleDataEvent Event Object

Language Version:

ActionScript 3.0

Runtime Versions:

Flash Player 10, AIR 1.5

Dispatched when the player requests new audio data.

Use this event when you want to manage dynamically generated audio. In this environment, the Sound object doesn't actually contain sound data. Instead, it acts as a socket for sound data that is being streamed to it through the use of the function you assign to this event.

In your function, you use the ByteArray.writeFloat() method to write to a ByteArray object (event.data) that contains the sampled data you want to play.

When you call Sound.play(), the player starts calling your event handler, asking for chunks of data that contain sound samples. The player continues to send events as the sound plays back until you stop providing data, or until SoundChannel.stop() is called.

The latency of the event varies from platform to platform, and could change in future versions of Flash Player. Don't depend on a specific latency, calculate it instead. To calculate the latency in ActionScript, use the formula: ((SampleDataEvent.position/44.1) - SoundChannelObject.position).

Provide between 2048 and 8192 samples in a SampleDataEvent object. For best performance, provide as many samples as possible. The fewer samples you provide, the more likely it is that clicks and pops will occur during playback. This behavior can differ on various platforms and can occur in various situations - for example, when resizing the browser. You might write code that works on one platform when you provide only 2048 samples, but that same code might not work as well when run on a different platform. If you require the lowest latency possible, consider making the amount of data user-selectable.

If you provide fewer than 2048 samples, Flash Player plays the remaining samples and then stops the sound as if the end of a sound file was reached, generating a SoundComplete event.

You can also use the Sound.extract() method to extract data from a Sound object, which you can then write to the dynamic stream for playback.

When you use this event with a Sound object, the only other Sound methods that are enabled are Sound.extract() and Sound.play(). Calling any other methods or properties results in an "invalid call" exception. All methods and properties of the SoundChannel object are still enabled.

View the examples

See also

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var mySound:Sound = new Sound();
function sineWaveGenerator(event:SampleDataEvent):void {
    for ( var c:int=0; c<8192; c++ ) {
        event.data.writeFloat(Math.sin((Number(c+event.position)/Math.PI/2))*0.25);
        event.data.writeFloat(Math.sin((Number(c+event.position)/Math.PI/2))*0.25);
    }
}

mySound.addEventListener(SampleDataEvent.SAMPLE_DATA,sineWaveGenerator);
mySound.play();