AutomaticGainControl


public class AutomaticGainControl
extends AudioEffect

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


Automatic Gain Control (AGC).

Automatic Gain Control (AGC) is an audio pre-processor 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 AudioRecord.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

Inherited constants

String ACTION_CLOSE_AUDIO_EFFECT_CONTROL_SESSION

Intent to signal to the effect control application or service that an audio session is closed and that effects should not be applied anymore.

String ACTION_DISPLAY_AUDIO_EFFECT_CONTROL_PANEL

Intent to launch an audio effect control panel UI.

String ACTION_OPEN_AUDIO_EFFECT_CONTROL_SESSION

Intent to signal to the effect control application or service that a new audio session is opened and requires audio effects to be applied.

int ALREADY_EXISTS

Internal operation status.

int CONTENT_TYPE_GAME

Value for EXTRA_CONTENT_TYPE when the type of content played is game audio

int CONTENT_TYPE_MOVIE

Value for EXTRA_CONTENT_TYPE when the type of content played is video or movie

int CONTENT_TYPE_MUSIC

Value for EXTRA_CONTENT_TYPE when the type of content played is music

int CONTENT_TYPE_VOICE

Value for EXTRA_CONTENT_TYPE when the type of content played is voice audio

String EFFECT_AUXILIARY

Effect connection mode is auxiliary.

String EFFECT_INSERT

Effect connection mode is insert.

String EFFECT_POST_PROCESSING

Effect connection mode is post processing.

String EFFECT_PRE_PROCESSING

Effect connection mode is pre processing.

int ERROR

Unspecified error.

int ERROR_BAD_VALUE

Operation failed due to bad parameter value.

int ERROR_DEAD_OBJECT

Operation failed due to dead remote object.

int ERROR_INVALID_OPERATION

Operation failed because it was requested in wrong state.

int ERROR_NO_INIT

Operation failed due to bad object initialization.

int ERROR_NO_MEMORY

Operation failed due to lack of memory.

String EXTRA_AUDIO_SESSION

Contains the ID of the audio session the effects should be applied to.

String EXTRA_CONTENT_TYPE

Indicates which type of content is played by the application.

String EXTRA_PACKAGE_NAME

Contains the package name of the calling application.

int SUCCESS

Successful operation.

Inherited fields

public static final UUID EFFECT_TYPE_AEC

UUID for Acoustic Echo Canceler (AEC)

public static final UUID EFFECT_TYPE_AGC

UUID for Automatic Gain Control (AGC)

public static final UUID EFFECT_TYPE_BASS_BOOST

UUID for bass boost effect

public static final UUID EFFECT_TYPE_DYNAMICS_PROCESSING

UUID for Dynamics Processing

public static final UUID EFFECT_TYPE_ENV_REVERB

UUID for environmental reverberation effect

public static final UUID EFFECT_TYPE_EQUALIZER

UUID for equalizer effect

public static final UUID EFFECT_TYPE_HAPTIC_GENERATOR

UUID for Haptic Generator.

public static final UUID EFFECT_TYPE_LOUDNESS_ENHANCER

UUID for Loudness Enhancer

public static final UUID EFFECT_TYPE_NS

UUID for Noise Suppressor (NS)

public static final UUID EFFECT_TYPE_PRESET_REVERB

UUID for preset reverberation effect

public static final UUID EFFECT_TYPE_VIRTUALIZER

UUID for virtualizer effect

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.

Inherited methods

void finalize()

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.

AudioEffect.Descriptor getDescriptor()

Get the effect descriptor.

boolean getEnabled()

Returns effect enabled state

int getId()

Returns effect unique identifier.

boolean hasControl()

Checks if this AudioEffect object is controlling the effect engine.

static Descriptor[] queryEffects()

Query all effects available on the platform.

void release()

Releases the native AudioEffect resources.

void setControlStatusListener(AudioEffect.OnControlStatusChangeListener listener)

Sets the listener AudioEffect notifies when the effect engine control is taken or returned.

void setEnableStatusListener(AudioEffect.OnEnableStatusChangeListener listener)

Sets the listener AudioEffect notifies when the effect engine is enabled or disabled.

int setEnabled(boolean enabled)

Enable or disable the effect.

Object clone()

Creates and returns a copy of this object.

boolean equals(Object obj)

Indicates whether some other object is "equal to" this one.

void finalize()

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.

final Class<?> getClass()

Returns the runtime class of this Object.

int hashCode()

Returns a hash code value for the object.

final void notify()

Wakes up a single thread that is waiting on this object's monitor.

final void notifyAll()

Wakes up all threads that are waiting on this object's monitor.

String toString()

Returns a string representation of the object.

final void wait(long timeoutMillis, int nanos)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

final void wait(long timeoutMillis)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

final void wait()

Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Public methods

create

Added in API level 16
public static AutomaticGainControl create (int audioSession)

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.

isAvailable

Added in API level 16
public static boolean isAvailable ()

Checks if the device implements automatic gain control.

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