Android APIs
public class

PresetReverb

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

Class Overview

A sound generated within a room travels in many directions. The listener first hears the direct sound from the source itself. Later, he or she hears discrete echoes caused by sound bouncing off nearby walls, the ceiling and the floor. As sound waves arrive after undergoing more and more reflections, individual reflections become indistinguishable and the listener hears continuous reverberation that decays over time. Reverb is vital for modeling a listener's environment. It can be used in music applications to simulate music being played back in various environments, or in games to immerse the listener within the game's environment. The PresetReverb class allows an application to configure the global reverb using a reverb preset. This is primarily used for adding some reverb in a music playback context. Applications requiring control over a more advanced environmental reverb are advised to use the EnvironmentalReverb class.

An application creates a PresetReverb object to instantiate and control a reverb engine in the audio framework.

The methods, parameter types and units exposed by the PresetReverb implementation are directly mapping those defined by the OpenSL ES 1.0.1 Specification (http://www.khronos.org/opensles/) for the SLPresetReverbItf interface. Please refer to this specification for more details.

The PresetReverb is an output mix auxiliary effect and should be created on Audio session 0. In order for a MediaPlayer or AudioTrack to be fed into this effect, they must be explicitely attached to it and a send level must be specified. Use the effect ID returned by getId() method to designate this particular effect when attaching it to the MediaPlayer or AudioTrack.

Creating a reverb on the output mix (audio session 0) requires permission MODIFY_AUDIO_SETTINGS

See AudioEffect class for more details on controlling audio effects.

Summary

Nested Classes
interface PresetReverb.OnParameterChangeListener The OnParameterChangeListener interface defines a method called by the PresetReverb when a parameter value has changed. 
class PresetReverb.Settings The Settings class regroups all preset reverb parameters. 
Constants
int PARAM_PRESET Preset.
short PRESET_LARGEHALL Reverb preset representing a large-sized hall suitable for a full orchestra
short PRESET_LARGEROOM Reverb preset representing a large-sized room suitable for live performances
short PRESET_MEDIUMHALL Reverb preset representing a medium-sized hall
short PRESET_MEDIUMROOM Reverb preset representing a medium room with a length of ten meters or less
short PRESET_NONE No reverb or reflections
short PRESET_PLATE Reverb preset representing a synthesis of the traditional plate reverb
short PRESET_SMALLROOM Reverb preset representing a small room less than five meters in length
[Expand]
Inherited Constants
From class android.media.audiofx.AudioEffect
[Expand]
Inherited Fields
From class android.media.audiofx.AudioEffect
Public Constructors
PresetReverb(int priority, int audioSession)
Class constructor.
Public Methods
short getPreset()
Gets current reverb preset.
PresetReverb.Settings getProperties()
Gets the preset reverb properties.
void setParameterListener(PresetReverb.OnParameterChangeListener listener)
Registers an OnParameterChangeListener interface.
void setPreset(short preset)
Enables a preset on the reverb.
void setProperties(PresetReverb.Settings settings)
Sets the preset reverb properties.
[Expand]
Inherited Methods
From class android.media.audiofx.AudioEffect
From class java.lang.Object

Constants

public static final int PARAM_PRESET

Added in API level 9

Preset. Parameter ID for PresetReverb.OnParameterChangeListener

Constant Value: 0 (0x00000000)

public static final short PRESET_LARGEHALL

Added in API level 9

Reverb preset representing a large-sized hall suitable for a full orchestra

Constant Value: 5 (0x00000005)

public static final short PRESET_LARGEROOM

Added in API level 9

Reverb preset representing a large-sized room suitable for live performances

Constant Value: 3 (0x00000003)

public static final short PRESET_MEDIUMHALL

Added in API level 9

Reverb preset representing a medium-sized hall

Constant Value: 4 (0x00000004)

public static final short PRESET_MEDIUMROOM

Added in API level 9

Reverb preset representing a medium room with a length of ten meters or less

Constant Value: 2 (0x00000002)

public static final short PRESET_NONE

Added in API level 9

No reverb or reflections

Constant Value: 0 (0x00000000)

public static final short PRESET_PLATE

Added in API level 9

Reverb preset representing a synthesis of the traditional plate reverb

Constant Value: 6 (0x00000006)

public static final short PRESET_SMALLROOM

Added in API level 9

Reverb preset representing a small room less than five meters in length

Constant Value: 1 (0x00000001)

Public Constructors

public PresetReverb (int priority, int audioSession)

Added in API level 9

Class constructor.

Parameters
priority the priority level requested by the application for controlling the PresetReverb engine. As the same engine can be shared by several applications, this parameter indicates how much the requesting application needs control of effect parameters. The normal priority is 0, above normal is a positive number, below normal a negative number.
audioSession system wide unique audio session identifier. If audioSession is not 0, the PresetReverb will be attached to the MediaPlayer or AudioTrack in the same audio session. Otherwise, the PresetReverb will apply to the output mix. As the PresetReverb is an auxiliary effect it is recommended to instantiate it on audio session 0 and to attach it to the MediaPLayer auxiliary output.
Throws
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
RuntimeException
IllegalArgumentException
UnsupportedOperationException

Public Methods

public short getPreset ()

Added in API level 9

Gets current reverb preset.

Returns
short the preset that is set at the moment.
Throws
IllegalStateException
IllegalArgumentException
UnsupportedOperationException
IllegalStateException
IllegalArgumentException

public PresetReverb.Settings getProperties ()

Added in API level 9

Gets the preset reverb properties. This method is useful when a snapshot of current preset reverb settings must be saved by the application.

Returns
PresetReverb.Settings a PresetReverb.Settings object containing all current parameters values
Throws
IllegalStateException
IllegalArgumentException
UnsupportedOperationException
IllegalStateException
IllegalArgumentException

public void setParameterListener (PresetReverb.OnParameterChangeListener listener)

Added in API level 9

Registers an OnParameterChangeListener interface.

Parameters
listener OnParameterChangeListener interface registered

public void setPreset (short preset)

Added in API level 9

Enables a preset on the reverb.

The reverb PRESET_NONE disables any reverb from the current output but does not free the resources associated with the reverb. For an application to signal to the implementation to free the resources, it must call the release() method.

Parameters
preset this must be one of the the preset constants defined in this class. e.g. PRESET_SMALLROOM
Throws
IllegalStateException
IllegalArgumentException
UnsupportedOperationException
IllegalStateException
IllegalArgumentException

public void setProperties (PresetReverb.Settings settings)

Added in API level 9

Sets the preset reverb properties. This method is useful when preset reverb settings have to be applied from a previous backup.

Parameters
settings a PresetReverb.Settings object containing the properties to apply
Throws
IllegalStateException
IllegalArgumentException
UnsupportedOperationException
IllegalStateException
IllegalArgumentException