ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Working with sound
}
g.endFill();
// right channel
g.lineStyle(0, 0xCC0066);
g.beginFill(0xCC0066, 0.5);
g.moveTo(CHANNEL_LENGTH * 2, PLOT_HEIGHT);
for (i = CHANNEL_LENGTH; i > 0; i--)
{
n = (bytes.readFloat() * PLOT_HEIGHT);
g.lineTo(i * 2, PLOT_HEIGHT - n);
}
g.lineTo(0, PLOT_HEIGHT);
g.endFill();
function onPlaybackComplete(event:Event)
{
removeEventListener(Event.ENTER_FRAME, onEnterFrame);
}
This example first loads and plays a sound file and then listens for the Event.ENTER_FRAME event which will trigger
the onEnterFrame() method while the sound plays. The onEnterFrame() method starts by calling the
SoundMixer.computeSpectrum() method, which stores the sound wave data in the bytes ByteArray object.
The sound waveform is plotted using the vector drawing API. A for loop cycles through the first 256 data values,
representing the left stereo channel, and draws a line from each point to the next using the Graphics.lineTo()
method. A second for loop cycles through the next set of 256 values, plotting them in reverse order this time, from
right to left. The resulting waveform plots can produce an interesting mirror-image effect, as shown in the following
image.
Last updated 6/6/2012
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