1. Thomas Lövgren, Flash developer
Introduction to
Flash ActionScript 3.0
Sound
Tid: ca 1,5 timme – 10 talet exempel
Thomas Lövgren, Flash developer

2. Introduction to Sound Lecture Outline
In this lecture we’ll discuss and practice the following topics:
AS3 Sound Architecture
Loading and playing External and Internal sound
Sound related classes
Coding a basic Sound Player
More sound functions & features
Microphone
Sound Visualization

3. Sound
AS3 Sound Architecture
In AS3 there are a lot of useful classes and methods for different kinds of sound functionality
Sound class: Is used to load, play and manage basic sound properties
SoundChannel class: Is used to create a separate channel for each new sound played (“channel” does not refer to left or right channel of stereo)
SoundMixer class: Creates a central mixer object through which all sound channels are mixed
SoundTransform class: Is used to control the volume, and panning between left and right stereo channels of a source
Microphone class: Let’s us control the gain, sampling rate and other properties of a Microphone

4. Internal and External Sound
In Flash there are basically two different ways of working with sound
Internal (sound in library) and External Sound (loading a sound)
It’s recommended that we use external sounds - by loading a sound into the application, we can keep the file size down
Examples of how to use the different types:
External sound: Load a sound file (MP3) into the application. This could be for example: background music, mp3 player etc.
Internal sound: Attach sound from Library (linkage). Small sounds (file size), for example sound effects for a game, button click-sounds etc.

5. Sound
Sound class (1/2)
The Sound class is used to load, play and manage basic sound functionalities
Some useful properties, methods & events for the Sound class:
Sound(), load(), play(), complete, bytesLoaded, bytesTotal, length etc
//create a new sound object
var my_sound:Sound = new Sound();

6. Sound class (2/2) (Load & play: External Sound)
Here is an example of how to load and play an external MP3 sound, and play it by using the Sound class
var my_sound:Sound = new Sound(); //create a new sound object
my_sound.load(new URLRequest("David Gray - Sail Away.mp3")); //load
my_sound.play(); //play sound
Note! It’s recommended that we also uses Events/functions to check if the
loading is complete

7. Sound
SoundChannel
The SoundChannel class, can be used to create a separate channel for each new sound played, stop a sound and/or get sound-peaks
An application can have multiple sound channels that are mixed together
Some useful properties, methods & events for this class:
Stop(), soundComplete, leftPeak, rightPeak, position etc
var my_sound:Sound = new Sound(); //create sound object
var my_channel:SoundChannel = new SoundChannel(); //create channel
my_sound.load(new URLRequest("David Gray - Sail Away.mp3")); //load
my_channel = my_sound.play(); //play sound through channel

8. Internal Sound (Sound in library/attach a sound)
For playing a sound from library – first we need to import the sound to Flash, then set up the Linkage property
in library
1. Right-click on the sound in library
2. Select Linkage (Properties in CS4)
3. Check the box “Export for ActionScript”
//create a new "library" sound & channel object
var library_sound:explode_sound = new explode_sound(); //sound object
var explode_channel:SoundChannel; //create channel object
explode_channel = library_sound.play(); //play sound through channel

9. Sound
SoundTransform class
The SoundTransform class, allows us to adjust the sound volume, and/or panning between left and right channel of a source
Some of the properties and methods for this class:
SoundTransform(), pan, volume etc
//function that adjust the volume by dragging a slider
function adjustVolume(event:Event):void{
var vol:Number = volume_mc.slider_mc.x / 100;
var st:SoundTransform = new SoundTransform(vol); }

10. Sound
SoundMixer class
The SoundMixer class creates a central mixer, changes to the mixer will affect all sounds
Some of the properties and methods for this class:
stopAll(), computeSpectrum(), bufferTime etc
//function that stops all sounds
function stopAllSound(event:MouseEvent):void{
SoundMixer.stopAll(); }

11. Sound
Stop, pause & play sound
There are a couple of more interesting sound features, for example if we want to stop, pause and play a sound we can write like:
//declare variable, get the sound position
var pausePos:Number = sound_channel.position;
sound_channel.stop();
...and at a later point we can start the sound at that position by writing:
sound_channel = my_sound.play(pausePos);

12. Sound
Sound Complete
If we want a sound to repeat when finished, we can add a listener to the Sound/channel object with the event SOUND_COMPLETE
//add listener to the sound through the channel object, call method
my_channel.addEventListener(Event.SOUND_COMPLETE, soundComplete);
//handler/function for repeating the sound
function soundComplete(event:Event):void{
my_channel = my_sound.play(); //play sound again }

13. Sound
Microphone
The Microphone class allows us to connect a microphone to Flash
By using the activityLevel method, it’s possible to for example animate the “activity” directly from the microphone
var my_mic:Microphone = Microphone.getMicrophone();
Security.showSettings(SecurityPanel.MICROPHONE);
my_mic.setLoopBack(true);
my_mic.setUseEchoSuppression(true);
stage.addEventListener(Event.ENTER_FRAME, onLoop);
function onLoop(event:Event){
line_mc.width = my_mic.activityLevel * 5;
activity_dyn.text = "Activity: " + String(my_mic.activityLevel) + "%";
width_dyn.text = "Line_mc Width: " + String(line_mc.width) + "px";
trace(my_mic.activityLevel); }

14. Sound
Sound visualization
By using the SoundMixer class and the computeSpectrum method, we can create interesting and fancy animations synchronized with the sound source