Packagecom.gestureworks.cml.element
Classpublic final class Microphone
InheritanceMicrophone Inheritance ObjectFactory Inheritance flash.events.EventDispatcher

Use the Microphone class to monitor or capture audio from a microphone.

To get a reference to a Microphone instance, use the Microphone.getMicrophone() method or the Microphone.getEnhancedMicrophone() method. An enhanced microphone instance can perform acoustic echo cancellation. Use acoustic echo cancellation to create real-time audio/video applications that don't require headsets.

Create a real-time chat application

To create a real-time chat application, capture audio and send it to Flash Media Server. Use the NetConnection and NetStream classes to send the audio stream to Flash Media Server. Flash Media Server can broadcast the audio to other clients. To create a chat application that doesn't require headsets, use acoustic echo cancellation. Acoustic echo cancellation prevents the feedback loop that occurs when audio enters a microphone, travels out the speakers, and enters the microphone again. To use acoustic echo cancellation, call the Microphone.getEnhancedMicrophone() method to get a reference to a Microphone instance. Set Microphone.enhancedOptions to an instance of the MicrophoneEnhancedOptions class to configure settings.

Play microphone audio locally

Call the Microphone setLoopback() method to route the microphone audio directly to the local computer or device audio output. Uncontrolled audio feedback is an inherent danger and is likely to occur whenever the audio output can be picked up by the microphone input. The setUseEchoSuppression() method can reduce, but not eliminate, the risk of feedback amplification.

Capture microphone audio for local recording or processing

To capture microphone audio, listen for the sampleData events dispatched by a Microphone instance. The SampleDataEvent object dispatched for this event contains the audio data.

For information about capturing video, see the Camera class.

Runtime microphone support

The Microphone class is not supported in Flash Player running in a mobile browser.

AIR profile support: The Microphone class is supported on desktop operating systems, but it is not supported on all mobile devices. It is not supported on AIR for TV devices. See AIR Profile Support for more information regarding API support across multiple profiles.

You can test for support at run time using the Microphone.isSupported property. Note that for AIR for TV devices, Microphone.isSupported is true but Microphone.getMicrophone() always returns null.

Privacy controls

Flash Player displays a Privacy dialog box that lets the user choose whether to allow or deny access to the microphone. Your application window size must be at least 215 x 138 pixels, the minimum size required to display the dialog box, or access is denied automatically.

Content running in the AIR application sandbox does not need permission to access the microphone and no dialog is displayed. AIR content running outside the application sandbox does require permission and the Privacy dialog is displayed.

EXAMPLE: The following example captures sound using echo suppression from a microphone after the user allows access to their computer's microphone. The Security.showSettings() method displays the Flash Player dialog box, which requests permission to access the user's microphone. The call to setLoopBack(true) reroutes input to the local speaker, so you can hear the sound while you run the example.

Two listeners listen for activity and status events. The activity event is dispatched at the start and end (if any) of the session and is captured by the activityHandler() method, which traces information on the event. The status event is dispatched if the attached microphone object reports any status information; it is captured and traced using the statusHandler() method.

Note: A microphone must be attached to your computer for this example to work correctly.

     
       package {
     import flash.display.Sprite;
     import flash.events.
     import flash.media.Microphone;
     import flash.system.Security;
     
       public class MicrophoneExample extends Sprite {
     public function MicrophoneExample() {
     var mic:Microphone = Microphone.getMicrophone();
     Security.showSettings("2");
     mic.setLoopBack(true);
     
       if (mic != null) {
     mic.setUseEchoSuppression(true);
     mic.addEventListener(ActivityEvent.ACTIVITY, activityHandler);
     mic.addEventListener(StatusEvent.STATUS, statusHandler);
     }
     }
     
       private function activityHandler(event:ActivityEvent):void {
     //trace("activityHandler: " + event);
     }
     
       private function statusHandler(event:StatusEvent):void {
     //trace("statusHandler: " + event);
     }
     }
     }
     

See also

Camera
LiveVideo


Public Properties
 PropertyDefined By
  activityLevel : Number
[read-only] The amount of sound the microphone is detecting.
Microphone
 InheritedcmlIndex : int
sets the index of cml
ObjectFactory
  codec : String
The codec to use for compressing audio.
Microphone
  enableVAD : Boolean
Enable Speex voice activity detection.
Microphone
  encodeQuality : int
The encoded speech quality when using the Speex codec.
Microphone
  framesPerPacket : int
Number of Speex speech frames transmitted in a packet (message).
Microphone
  gain : Number
The amount by which the microphone boosts the signal.
Microphone
 Inheritedid : String
sets the id
ObjectFactory
  index : int
[read-only] The index of the microphone, as reflected in the array returned by Microphone.names.
Microphone
  isSupported : Boolean
[read-only] The isSupported property is set to true if the Microphone class is supported on the current platform, otherwise it is set to false.
Microphone
  muted : Boolean
[read-only] Specifies whether the user has denied access to the microphone (true) or allowed access (false).
Microphone
  name : String
[read-only] The name of the current sound capture device, as returned by the sound capture hardware.
Microphone
  names : Array
[read-only] An array of strings containing the names of all available sound capture devices.
Microphone
  noiseSuppressionLevel : int
Maximum attenuation of the noise in dB (negative number) used for Speex encoder.
Microphone
 InheritedpropertyStates : Array
Deprecated: Please Use state
ObjectFactory
  rate : int
The rate at which the microphone is capturing sound, in kHz.
Microphone
  silenceLevel : Number
[read-only] The amount of sound required to activate the microphone and dispatch the activity event.
Microphone
  silenceTimeout : int
[read-only] The number of milliseconds between the time the microphone stops detecting sound and the time the activity event is dispatched.
Microphone
  soundTransform : SoundTransform
Controls the sound of this microphone object when it is in loopback mode.
Microphone
 Inheritedstate : Array
property states array
ObjectFactory
  useEchoSuppression : Boolean
[read-only] Set to true if echo suppression is enabled; false otherwise.
Microphone
Public Methods
 MethodDefined By
  
Constructor
Microphone
 Inherited
clone():*
Returns clone of self
ObjectFactory
  
dispose():void
[override] Dispose method
Microphone
  
getMicrophone(index:int = -1):Microphone
Returns a reference to a Microphone object for capturing audio.
Microphone
 Inherited
parseCML(cml:XMLList):XMLList
parses cml file
ObjectFactory
 Inherited
postparseCML(cml:XMLList):void
postparse method
ObjectFactory
  
setLoopBack(state:Boolean = true):void
Routes audio captured by a microphone to the local speakers.
Microphone
  
setSilenceLevel(silenceLevel:Number, timeout:int = -1):void
Sets the minimum input level that should be considered sound and (optionally) the amount of silent time signifying that silence has actually begun.
Microphone
  
setUseEchoSuppression(useEchoSuppression:Boolean):void
Specifies whether to use the echo suppression feature of the audio codec.
Microphone
 Inherited
updateProperties(state:Number = 0):void
update the properties
ObjectFactory
Events
 Event Summary Defined By
  Dispatched when a microphone starts or stops recording due to detected silence.Microphone
  Dispatched when the microphone has sound data in the buffer.Microphone
  Dispatched when a microphone reports its status.Microphone
Property Detail
activityLevelproperty
activityLevel:Number  [read-only]

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

The amount of sound the microphone is detecting. Values range from 0 (no sound is detected) to 100 (very loud sound is detected). The value of this property can help you determine a good value to pass to the Microphone.setSilenceLevel() method. If the microphone muted property is true, the value of this property is always -1.


Implementation
    public function get activityLevel():Number
codecproperty 
codec:String

Language Version : ActionScript 3.0
Runtime Versions : Flash Player 10, AIR 1.5

The codec to use for compressing audio. Available codecs are Nellymoser (the default) and Speex. The enumeration class SoundCodec contains the various values that are valid for the codec property. If you use the Nellymoser codec, you can set the sample rate using Microphone.rate(). If you use the Speex codec, the sample rate is set to 16 kHz.Speex includes voice activity detection (VAD) and automatically reduces bandwidth when no voice is detected. When using the Speex codec, Adobe recommends that you set the silence level to 0. To set the silence level, use the Microphone.setSilenceLevel() method.


Implementation
    public function get codec():String
    public function set codec(value:String):void
enableVADproperty 
enableVAD:Boolean

Language Version : ActionScript 3.0
Runtime Versions : Flash Player 10.1, AIR 2

Enable Speex voice activity detection.


Implementation
    public function get enableVAD():Boolean
    public function set enableVAD(value:Boolean):void
encodeQualityproperty 
encodeQuality:int

Language Version : ActionScript 3.0
Runtime Versions : Flash Player 10, AIR 1.5

The encoded speech quality when using the Speex codec. Possible values are from 0 to 10. The default value is 6. Higher numbers represent higher quality but require more bandwidth, as shown in the following table. The bit rate values that are listed represent net bit rates and do not include packetization overhead. Quality valueRequired bit rate (kilobits per second)0 3.9515.7527.7539.80412.8516.8620.6723.8827.8934.21042.2


Implementation
    public function get encodeQuality():int
    public function set encodeQuality(value:int):void
framesPerPacketproperty 
framesPerPacket:int

Language Version : ActionScript 3.0
Runtime Versions : Flash Player 10, AIR 1.5

Number of Speex speech frames transmitted in a packet (message). Each frame is 20 ms long. The default value is two frames per packet. The more Speex frames in a message, the lower the bandwidth required but the longer the delay in sending the message. Fewer Speex frames increases bandwidth required but reduces delay.


Implementation
    public function get framesPerPacket():int
    public function set framesPerPacket(value:int):void
gainproperty 
gain:Number

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

The amount by which the microphone boosts the signal. Valid values are 0 to 100. The default value is 50.


Implementation
    public function get gain():Number
    public function set gain(value:Number):void
indexproperty 
index:int  [read-only]

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

The index of the microphone, as reflected in the array returned by Microphone.names.


Implementation
    public function get index():int
isSupportedproperty 
isSupported:Boolean  [read-only]

Language Version : ActionScript 3.0
Runtime Versions : Flash Player 10.1, AIR 2

The isSupported property is set to true if the Microphone class is supported on the current platform, otherwise it is set to false.


Implementation
    public function get isSupported():Boolean
mutedproperty 
muted:Boolean  [read-only]

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

Specifies whether the user has denied access to the microphone (true) or allowed access (false). When this value changes, a status event is dispatched. For more information, see Microphone.getMicrophone().


Implementation
    public function get muted():Boolean
nameproperty 
name:String  [read-only]

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

The name of the current sound capture device, as returned by the sound capture hardware.


Implementation
    public function get name():String
namesproperty 
names:Array  [read-only]

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

An array of strings containing the names of all available sound capture devices. The names are returned without having to display the Flash Player Privacy Settings panel to the user. This array provides the zero-based index of each sound capture device and the number of sound capture devices on the system, through the Microphone.names.length property. For more information, see the Array class entry. Calling Microphone.names requires an extensive examination of the hardware, and it may take several seconds to build the array. In most cases, you can just use the default microphone.Note: To determine the name of the current microphone, use the name property.


Implementation
    public function get names():Array
noiseSuppressionLevelproperty 
noiseSuppressionLevel:int

Language Version : ActionScript 3.0
Runtime Versions : Flash Player 10.1, AIR 2

Maximum attenuation of the noise in dB (negative number) used for Speex encoder. If enabled, noise suppression is applied to sound captured from Microphone before Speex compression. Set to 0 to disable noise suppression. Noise suppression is enabled by default with maximum attenuation of -30 dB. Ignored when Nellymoser codec is selected.


Implementation
    public function get noiseSuppressionLevel():int
    public function set noiseSuppressionLevel(value:int):void
rateproperty 
rate:int

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

The rate at which the microphone is capturing sound, in kHz. Acceptable values are 5, 8, 11, 22, and 44. The default value is 8 kHz if your sound capture device supports this value. Otherwise, the default value is the next available capture level above 8 kHz that your sound capture device supports, usually 11 kHz. Note: The actual rate differs slightly from the rate value, as noted in the following table:rate valueActual frequency4444,100 Hz2222,050 Hz1111,025 Hz88,000 Hz55,512 Hz


Implementation
    public function get rate():int
    public function set rate(value:int):void
silenceLevelproperty 
silenceLevel:Number  [read-only]

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

The amount of sound required to activate the microphone and dispatch the activity event. The default value is 10.


Implementation
    public function get silenceLevel():Number
silenceTimeoutproperty 
silenceTimeout:int  [read-only]

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

The number of milliseconds between the time the microphone stops detecting sound and the time the activity event is dispatched. The default value is 2000 (2 seconds). To set this value, use the Microphone.setSilenceLevel() method.


Implementation
    public function get silenceTimeout():int
soundTransformproperty 
soundTransform:SoundTransform

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

Controls the sound of this microphone object when it is in loopback mode.


Implementation
    public function get soundTransform():SoundTransform
    public function set soundTransform(value:SoundTransform):void
useEchoSuppressionproperty 
useEchoSuppression:Boolean  [read-only]

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

Set to true if echo suppression is enabled; false otherwise. The default value is false unless the user has selected Reduce Echo in the Flash Player Microphone Settings panel.


Implementation
    public function get useEchoSuppression():Boolean
Constructor Detail
Microphone()Constructor
public function Microphone()

Constructor

Method Detail
dispose()method
override public function dispose():void

Dispose method

getMicrophone()method 
public function getMicrophone(index:int = -1):Microphone

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

Returns a reference to a Microphone object for capturing audio. To begin capturing the audio, you must attach the Microphone object to a NetStream object (see NetStream.attachAudio()). Multiple calls to Microphone.getMicrophone() reference the same microphone. Thus, if your code contains the lines mic1 = Microphone.getMicrophone() and mic2 = Microphone.getMicrophone() , both mic1 and mic2 reference the same (default) microphone. In general, you should not pass a value for index. Simply call air.Microphone.getMicrophone() to return a reference to the default microphone. Using the Microphone Settings section in the Flash Player settings panel, the user can specify the default microphone the application should use. (The user access the Flash Player settings panel by right-clicking Flash Player content running in a web browser.) If you pass a value for index, you can reference a microphone other than the one the user chooses. You can use index in rare cases—for example, if your application is capturing audio from two microphones at the same time. Content running in Adobe AIR also uses the Flash Player setting for the default microphone. Use the Microphone.index property to get the index value of the current Microphone object. You can then pass this value to other methods of the Microphone class. When a SWF file tries to access the object returned by Microphone.getMicrophone() —for example, when you call NetStream.attachAudio()— Flash Player displays a Privacy dialog box that lets the user choose whether to allow or deny access to the microphone. (Make sure your Stage size is at least 215 x 138 pixels; this is the minimum size Flash Player requires to display the dialog box.) When the user responds to this dialog box, a status event is dispatched that indicates the user's response. You can also check the Microphone.muted property to determine if the user has allowed or denied access to the microphone. If Microphone.getMicrophone() returns null, either the microphone is in use by another application, or there are no microphones installed on the system. To determine whether any microphones are installed, use Microphones.names.length. To display the Flash Player Microphone Settings panel, which lets the user choose the microphone to be referenced by Microphone.getMicrophone, use Security.showSettings().

Parameters

index:int (default = -1) — The index value of the microphone.

Returns
Microphone — A reference to a Microphone object for capturing audio.
setLoopBack()method 
public function setLoopBack(state:Boolean = true):void

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

Routes audio captured by a microphone to the local speakers.

Parameters

state:Boolean (default = true)

setSilenceLevel()method 
public function setSilenceLevel(silenceLevel:Number, timeout:int = -1):void

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

Sets the minimum input level that should be considered sound and (optionally) the amount of silent time signifying that silence has actually begun. To prevent the microphone from detecting sound at all, pass a value of 100 for silenceLevel; the activity event is never dispatched. To determine the amount of sound the microphone is currently detecting, use Microphone.activityLevel. Speex includes voice activity detection (VAD) and automatically reduces bandwidth when no voice is detected. When using the Speex codec, Adobe recommends that you set the silence level to 0.Activity detection is the ability to detect when audio levels suggest that a person is talking. When someone is not talking, bandwidth can be saved because there is no need to send the associated audio stream. This information can also be used for visual feedback so that users know they (or others) are silent.Silence values correspond directly to activity values. Complete silence is an activity value of 0. Constant loud noise (as loud as can be registered based on the current gain setting) is an activity value of 100. After gain is appropriately adjusted, your activity value is less than your silence value when you're not talking; when you are talking, the activity value exceeds your silence value.This method is similar to Camera.setMotionLevel(); both methods are used to specify when the activity event is dispatched. However, these methods have a significantly different impact on publishing streams:Camera.setMotionLevel() is designed to detect motion and does not affect bandwidth usage. Even if a video stream does not detect motion, video is still sent.Microphone.setSilenceLevel() is designed to optimize bandwidth. When an audio stream is considered silent, no audio data is sent. Instead, a single message is sent, indicating that silence has started.

Parameters

silenceLevel:Number — The amount of sound required to activate the microphone and dispatch the activity event. Acceptable values range from 0 to 100.
 
timeout:int (default = -1) — The number of milliseconds that must elapse without activity before Flash Player or Adobe AIR considers sound to have stopped and dispatches the dispatch event. The default value is 2000 (2 seconds). (Note: The default value shown in the signature, -1, is an internal value that indicates to Flash Player or Adobe AIR to use 2000.)

setUseEchoSuppression()method 
public function setUseEchoSuppression(useEchoSuppression:Boolean):void

Language Version : ActionScript 3.0
Runtime Versions : AIR 1.0, Flash Player 9

Specifies whether to use the echo suppression feature of the audio codec. The default value is false unless the user has selected Reduce Echo in the Flash Player Microphone Settings panel. Echo suppression is an effort to reduce the effects of audio feedback, which is caused when sound going out the speaker is picked up by the microphone on the same system. (This is different from acoustic echo cancellation, which completely removes the feedback. The setUseEchoSuppression() method is ignored when you call the getEnhancedMicrophone() method to use acoustic echo cancellation.)Generally, echo suppression is advisable when the sound being captured is played through speakers — instead of a headset —. If your SWF file allows users to specify the sound output device, you may want to call Microphone.setUseEchoSuppression(true) if they indicate they are using speakers and will be using the microphone as well. Users can also adjust these settings in the Flash Player Microphone Settings panel.

Parameters

useEchoSuppression:Boolean — A Boolean value indicating whether to use echo suppression (true) or not (false).

Event Detail
activity Event
Event Object Type: flash.events.ActivityEvent
ActivityEvent.type property = flash.events.ActivityEvent.ACTIVITY

Dispatched when a microphone starts or stops recording due to detected silence.

sampleData Event  
Event Object Type: flash.events.SampleDataEvent
SampleDataEvent.type property = flash.events.SampleDataEvent.SAMPLE_DATA

Dispatched when the microphone has sound data in the buffer.

status Event  
Event Object Type: flash.events.StatusEvent
StatusEvent.type property = flash.events.StatusEvent.STATUS

Dispatched when a microphone reports its status.