Android APIs
public class

AutomaticGainControl

extends AudioEffect
java.lang.Object
   ↳ android.media.audiofx.AudioEffect
     ↳ android.media.audiofx.AutomaticGainControl

Class Overview

Automatic Gain Control (AGC).

Automatic Gain Control (AGC) is an audio pre-processing which automatically normalizes the output of the captured signal by boosting or lowering input from the microphone to match a preset level so that the output signal level is virtually constant. AGC can be used by applications where the input signal dynamic range is not important but where a constant strong capture level is desired.

An application creates a AutomaticGainControl object to instantiate and control an AGC engine in the audio framework.

To attach the AutomaticGainControl to a particular AudioRecord, specify the audio session ID of this AudioRecord when creating the AutomaticGainControl. The audio session is retrieved by calling getAudioSessionId() on the AudioRecord instance.

On some devices, an AGC can be inserted by default in the capture path by the platform according to the MediaRecorder.AudioSource used. The application should call AutomaticGainControl.getEnable() after creating the AGC to check the default AGC activation state on a particular AudioRecord session.

See AudioEffect class for more details on controlling audio effects.

Summary

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Inherited Constants
From class android.media.audiofx.AudioEffect
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Inherited Fields
From class android.media.audiofx.AudioEffect
Public Methods
static AutomaticGainControl create(int audioSession)
Creates an AutomaticGainControl and attaches it to the AudioRecord on the audio session specified.
static boolean isAvailable()
Checks if the device implements automatic gain control.
[Expand]
Inherited Methods
From class android.media.audiofx.AudioEffect
From class java.lang.Object

Public Methods

public static AutomaticGainControl create (int audioSession)

Added in API level 16

Creates an AutomaticGainControl and attaches it to the AudioRecord on the audio session specified.

Parameters
audioSession int: system wide unique audio session identifier. The AutomaticGainControl will be applied to the AudioRecord with the same audio session.
Returns
AutomaticGainControl AutomaticGainControl created or null if the device does not implement AGC.

public static boolean isAvailable ()

Added in API level 16

Checks if the device implements automatic gain control.

Returns
boolean true if the device implements automatic gain control, false otherwise.