Sound

1
Sound
Introduction to
Flash ActionScript 3.0
Thomas Lövgren, Flash developer thomas.lovgren_at_hum
lab.umu.se
2
Introduction to Sound
Sound

• Lecture Outline
• In this lecture well 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
AS3 Sound Architecture
Sound

• 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 Lets us control the gain,
  sampling rate and other properties of a
  Microphone

4
Internal and External Sound
Sound

• In Flash there are basically two different ways
  of working with sound
• Internal (sound in library) and External Sound
  (loading a sound)
• Its 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 class (1/2)
Sound

• 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_soundSound new Sound()

6
Sound class (2/2)(Load play External Sound)
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_soundSound new Sound() //create a new
  sound object
• my_sound.load(new URLRequest("David Gray - Sail
  Away.mp3")) //load
• my_sound.play() //play sound

• Note! Its recommended that we also uses
  Events/functions to check if the
• loading is complete

7
SoundChannel
Sound

• 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_soundSound new Sound() //create sound
  object
• var my_channelSoundChannel 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)
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_soundexplode_sound new
  explode_sound() //sound object
• var explode_channelSoundChannel //create
  channel object
• explode_channel library_sound.play() //play
  sound through channel

9
SoundTransform class
Sound

• 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(eventEvent)void
• var volNumber volume_mc.slider_mc.x / 100
• var stSoundTransform new SoundTransform(vol)

10
SoundMixer class
Sound

• 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(eventMouseEvent)void
• SoundMixer.stopAll()

11
Stop, pause play sound
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 pausePosNumber 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 Complete
Sound

• 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(eventEvent)void
• my_channel my_sound.play() //play sound again

13
Microphone
Sound

• The Microphone class allows us to connect a
  microphone to Flash
• By using the activityLevel method, its possible
  to for example animate the activity directly
  from the microphone
• var my_micMicrophone Microphone.getMicrophone()
  
• Security.showSettings(SecurityPanel.MICROPHONE)
• my_mic.setLoopBack(true)
• my_mic.setUseEchoSuppression(true)
• stage.addEventListener(Event.ENTER_FRAME,
  onLoop)
• function onLoop(eventEvent)
• 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 visualization
Sound

• By using the SoundMixer class and the
  computeSpectrum method, we can create interesting
  and fancy animations synchronized with the sound
  source