AutomaticGainControl

Kotlin |Java

open class AutomaticGainControl : AudioEffect

kotlin.Any
↳	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 android.media.AudioRecord, specify the audio session ID of this AudioRecord when creating the AutomaticGainControl. The audio session is retrieved by calling android.media.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 android.media.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 android.media.audiofx.AudioEffect class for more details on controlling audio effects.

Summary

Inherited constants

From class AudioEffect

`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. The effect control application receiving this intent will delete all effects on this session and store current settings in package specific storage. The calling package name is indicated by the `EXTRA_PACKAGE_NAME` extra and the audio session ID by the `EXTRA_AUDIO_SESSION` extra. Both extras are mandatory. It is good practice for applications to broadcast this intent when music playback stops and/or when exiting to free system resources consumed by audio effect engines.
`String`	`ACTION_DISPLAY_AUDIO_EFFECT_CONTROL_PANEL` Intent to launch an audio effect control panel UI. The goal of this intent is to enable separate implementations of music/media player applications and audio effect control application or services. This will allow platform vendors to offer more advanced control options for standard effects or control for platform specific effects. The intent carries a number of extras used by the player application to communicate necessary pieces of information to the control panel application. The calling application must use the android.app.Activity#startActivityForResult(Intent, int) method to launch the control panel so that its package name is indicated and used by the control panel application to keep track of changes for this particular application. The `EXTRA_AUDIO_SESSION` extra will indicate an audio session to which the audio effects should be applied. If no audio session is specified, either one of the follownig will happen: - If an audio session was previously opened by the calling application with `ACTION_OPEN_AUDIO_EFFECT_CONTROL_SESSION` intent, the effect changes will be applied to that session. - If no audio session is opened, the changes will be stored in the package specific storage area and applied whenever a new audio session is opened by this application. The `EXTRA_CONTENT_TYPE` extra will help the control panel application customize both the UI layout and the default audio effect settings if none are already stored for the calling application.
`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. This is different from `ACTION_DISPLAY_AUDIO_EFFECT_CONTROL_PANEL` in that no UI should be displayed in this case. Music player applications can broadcast this intent before starting playback to make sure that any audio effect settings previously selected by the user are applied. The effect control application receiving this intent will look for previously stored settings for the calling application, create all required audio effects and apply the effect settings to the specified audio session. The calling package name is indicated by the `EXTRA_PACKAGE_NAME` extra and the audio session ID by the `EXTRA_AUDIO_SESSION` extra. Both extras are mandatory. If no stored settings are found for the calling application, default settings for the content type indicated by `EXTRA_CONTENT_TYPE` will be applied. The default settings for a given content type are platform specific.
`Int`	`ALREADY_EXISTS` Internal operation status. Not returned by any method.
`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. Auxiliary effects must be created on session 0 (global output mix). In order for a MediaPlayer or AudioTrack to be fed into this effect, they must be explicitely attached to this effect and a send level must be specified. Use the effect ID returned by `getId()` to designate this particular effect when attaching it to the MediaPlayer or AudioTrack.
`String`	`EFFECT_INSERT` Effect connection mode is insert. Specifying an audio session ID when creating the effect will insert this effect after all players in the same audio session.
`String`	`EFFECT_POST_PROCESSING` Effect connection mode is post processing. The audio post processing effects are attached to an audio output stream or device
`String`	`EFFECT_PRE_PROCESSING` Effect connection mode is pre processing. The audio pre processing effects are attached to an audio input stream or device
`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. This extra is for use with `ACTION_DISPLAY_AUDIO_EFFECT_CONTROL_PANEL`, `ACTION_OPEN_AUDIO_EFFECT_CONTROL_SESSION` and `ACTION_CLOSE_AUDIO_EFFECT_CONTROL_SESSION` intents. The extra value is of type int and is the audio session ID.
`String`	`EXTRA_CONTENT_TYPE` Indicates which type of content is played by the application. This extra is for use with `ACTION_DISPLAY_AUDIO_EFFECT_CONTROL_PANEL` and `ACTION_OPEN_AUDIO_EFFECT_CONTROL_SESSION` intents. This information is used by the effect control application to customize UI and select appropriate default effect settings. The content type is one of the following: `CONTENT_TYPE_MUSIC` `CONTENT_TYPE_MOVIE` `CONTENT_TYPE_GAME` `CONTENT_TYPE_VOICE` If omitted, the content type defaults to `CONTENT_TYPE_MUSIC`.
`String`	`EXTRA_PACKAGE_NAME` Contains the package name of the calling application. This extra is for use with `ACTION_OPEN_AUDIO_EFFECT_CONTROL_SESSION` and `ACTION_CLOSE_AUDIO_EFFECT_CONTROL_SESSION` intents. The extra value is a string containing the full package name.
`Int`	`SUCCESS` Successful operation.

Public methods
open static AutomaticGainControl!	`create(audioSession: Int)` Creates an AutomaticGainControl and attaches it to the AudioRecord on the audio session specified.
open static Boolean	`isAvailable()` Checks if the device implements automatic gain control.

Inherited functions

From class AudioEffect

`Unit`	`finalize()`
`AudioEffect.Descriptor!`	`getDescriptor()` Get the effect descriptor.
`Boolean`	`getEnabled()` Returns effect enabled state
`Int`	`getId()` Returns effect unique identifier. This system wide unique identifier can be used to attach this effect to a MediaPlayer or an AudioTrack when the effect is an auxiliary effect (Reverb)
`Boolean`	`hasControl()` Checks if this AudioEffect object is controlling the effect engine.
`Array<AudioEffect.Descriptor!>!`	`queryEffects()` Query all effects available on the platform. Returns an array of `android.media.audiofx.AudioEffect.Descriptor` objects
`Unit`	`release()` Releases the native AudioEffect resources. It is a good practice to release the effect engine when not in use as control can be returned to other applications or the native resources released.
`Unit`	`setControlStatusListener(listener: AudioEffect.OnControlStatusChangeListener!)` Sets the listener AudioEffect notifies when the effect engine control is taken or returned.
`Unit`	`setEnableStatusListener(listener: AudioEffect.OnEnableStatusChangeListener!)` Sets the listener AudioEffect notifies when the effect engine is enabled or disabled.
`Int`	`setEnabled(enabled: Boolean)` Enable or disable the effect. Creating an audio effect does not automatically apply this effect on the audio source. It creates the resources necessary to process this effect but the audio signal is still bypassed through the effect engine. Calling this method will make that the effect is actually applied or not to the audio content being played in the corresponding audio session.

Inherited properties

From class AudioEffect

`UUID!`	`EFFECT_TYPE_AEC` UUID for Acoustic Echo Canceler (AEC)
`UUID!`	`EFFECT_TYPE_AGC` UUID for Automatic Gain Control (AGC)
`UUID!`	`EFFECT_TYPE_BASS_BOOST` UUID for bass boost effect
`UUID!`	`EFFECT_TYPE_DYNAMICS_PROCESSING` UUID for Dynamics Processing
`UUID!`	`EFFECT_TYPE_ENV_REVERB` UUID for environmental reverberation effect
`UUID!`	`EFFECT_TYPE_EQUALIZER` UUID for equalizer effect
`UUID`	`EFFECT_TYPE_HAPTIC_GENERATOR` UUID for Haptic Generator.
`UUID!`	`EFFECT_TYPE_LOUDNESS_ENHANCER` UUID for Loudness Enhancer
`UUID!`	`EFFECT_TYPE_NS` UUID for Noise Suppressor (NS)
`UUID!`	`EFFECT_TYPE_PRESET_REVERB` UUID for preset reverberation effect
`UUID!`	`EFFECT_TYPE_VIRTUALIZER` UUID for virtualizer effect

Public methods

create

Added in API level 16

open static fun create(audioSession: Int): AutomaticGainControl!

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.

Return
`AutomaticGainControl!`	AutomaticGainControl created or null if the device does not implement AGC.

isAvailable

Added in API level 16

open static fun isAvailable(): Boolean

Checks if the device implements automatic gain control.

Return
`Boolean`	true if the device implements automatic gain control, false otherwise.