ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with sound
import flash.events.Event;
import flash.media.Sound;
import flash.media.SoundChannel;
import flash.media.SoundMixer;
import flash.net.URLRequest;
var snd:Sound = new Sound();
var req:URLRequest = new URLRequest("bigSound.mp3");
snd.load(req);
var panCounter:Number = 0;
var trans:SoundTransform;
trans = new SoundTransform(1, 0);
var channel:SoundChannel = snd.play(0, 1, trans);
channel.addEventListener(Event.SOUND_COMPLETE, onPlaybackComplete);
addEventListener(Event.ENTER_FRAME, onEnterFrame);
function onEnterFrame(event:Event):void
{
trans.pan = Math.sin(panCounter);
channel.soundTransform = trans; // or SoundMixer.soundTransform = trans;
panCounter += 0.05;
}
function onPlaybackComplete(event:Event):void
{
removeEventListener(Event.ENTER_FRAME, onEnterFrame);
}
This code starts by loading a sound file and then creating a new SoundTransform object with volume set to 1 (full
volume) and pan set to 0 (evenly balanced between left and right). Then it calls the snd.play() method, passing the
SoundTransform object as a parameter.
While the sound plays, the onEnterFrame() method executes repeatedly. The onEnterFrame() method uses the
Math.sin() function to generate a value between -1 and 1, a range that corresponds to the acceptable values of the
SoundTransform.pan property. The SoundTransform object’s pan property is set to the new value, and then the
channel’s soundTransform property is set to use the altered SoundTransform object.
To run this example, replace the filename bigSound.mp3 with the name of a local mp3 file. Then run the example. You
should hear the left channel volume getting louder while the right channel volume gets softer, and vice versa.
In this example, the same effect could be achieved by setting the soundTransform property of the SoundMixer class.
However, that would affect the panning of all sounds currently playing, not just the single sound being played by this
SoundChannel object.
Working with sound metadata
Flash Player 9 and later, Adobe AIR 1.0 and later
Sound files that use the mp3 format can contain additional data about the sound in the form of ID3 tags.
Last updated 6/6/2012
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