ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with sound
var mySound:Sound = new Sound();
mySound.addEventListener(SampleDataEvent.SAMPLE_DATA, sineWaveGenerator);
mySound.play();
function sineWaveGenerator(event:SampleDataEvent):void
{
for (var i:int = 0; i < 8192; i++)
{
var n:Number = Math.sin((i + event.position) / Math.PI / 4);
event.data.writeFloat(n);
event.data.writeFloat(n);
}
}
When you call Sound.play(), the application starts calling your event handler, requesting sound sample data. The
application continues to send events as the sound plays back until you stop providing data, or until you call
SoundChannel.stop().
The latency of the event varies from platform to platform, and could change in future versions of Flash Player and AIR.
Do not depend on a specific latency; calculate it instead. To calculate the latency, use the following formula:
(SampleDataEvent.position / 44.1) - SoundChannelObject.position
Provide from 2048 through 8192 samples to the data property of the SampleDataEvent object (for each call to the
event listener). For best performance, provide as many samples as possible (up to 8192). 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. Code that works on one
platform when you provide only 2048 sample 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 (per call to the sampleData event listener), the application stops after playing
the remaining samples. The SoundChannel object then dispatches a SoundComplete event.
Modifying sound from mp3 data
Flash Player 10 and later, Adobe AIR 1.5 and later
You use the Sound.extract() method to extract data from a Sound object. You can use (and modify) that data to
write to the dynamic stream of another Sound object for playback. For example, the following code uses the bytes of a
loaded MP3 file and passes them through a filter function, upOctave():
Last updated 6/6/2012
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