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.net.URLRequest;
var snd:Sound = new Sound();
var req:URLRequest = new URLRequest("smallSound.mp3");
snd.load(req);
var channel:SoundChannel = snd.play();
channel.addEventListener(Event.SOUND_COMPLETE, onPlaybackComplete);
public function onPlaybackComplete(event:Event)
{
trace("The sound has finished playing.");
}
The SoundChannel class does not dispatch progress events during playback. To report on playback progress, your
application can set up its own timing mechanism and track the position of the sound playhead.
To calculate what percentage of a sound has been played, you can divide the value of the SoundChannel.position
property by the length of the sound data that’s being played:
var playbackPercent:uint = 100 * (channel.position / snd.length);
However, this code only reports accurate playback percentages if the sound data was fully loaded before playback
began. The Sound.length property shows the size of the sound data that is currently loaded, not the eventual size of
the entire sound file. To track the playback progress of a streaming sound that is still loading, your application should
estimate the eventual size of the full sound file and use that value in its calculations. You can estimate the eventual
length of the sound data using the bytesLoaded and bytesTotal properties of the Sound object, as follows:
var estimatedLength:int =
Math.ceil(snd.length / (snd.bytesLoaded / snd.bytesTotal));
var playbackPercent:uint = 100 * (channel.position / estimatedLength);
The following code loads a larger sound file and uses the Event.ENTER_FRAME event as its timing mechanism for
showing playback progress. It periodically reports on the playback percentage, which is calculated as the current
position value divided by the total length of the sound data:
Last updated 6/6/2012
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