EnvironmentalReverb

public class EnvironmentalReverb
extends AudioEffect

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


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 EnvironmentalReverb class allows an application to control each reverb engine property in a global reverb environment and is more suitable for games. For basic control, more suitable for music applications, it is recommended to use the PresetReverb class.

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

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

The EnvironmentalReverb 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 Manifest.permission.MODIFY_AUDIO_SETTINGS

See AudioEffect class for more details on controlling audio effects.

Summary

Nested classes

interface EnvironmentalReverb.OnParameterChangeListener

The OnParameterChangeListener interface defines a method called by the EnvironmentalReverb when a parameter value has changed. 

class EnvironmentalReverb.Settings

The Settings class regroups all environmental reverb parameters. 

Constants

int PARAM_DECAY_HF_RATIO

Decay HF ratio.

int PARAM_DECAY_TIME

Decay time.

int PARAM_DENSITY

Density.

int PARAM_DIFFUSION

Diffusion.

int PARAM_REFLECTIONS_DELAY

Early reflections delay.

int PARAM_REFLECTIONS_LEVEL

Early reflections level.

int PARAM_REVERB_DELAY

Reverb delay.

int PARAM_REVERB_LEVEL

Reverb level.

int PARAM_ROOM_HF_LEVEL

Room HF level.

int PARAM_ROOM_LEVEL

Room level.

Inherited constants

Inherited fields

Public constructors

EnvironmentalReverb(int priority, int audioSession)

Class constructor.

Public methods

short getDecayHFRatio()

Gets the ratio of high frequency decay time (at 5 kHz) relative to low frequencies.

int getDecayTime()

Gets the decay time.

short getDensity()

Gets the density level.

short getDiffusion()

Gets diffusion level.

EnvironmentalReverb.Settings getProperties()

Gets the environmental reverb properties.

int getReflectionsDelay()

Gets the reflections delay.

short getReflectionsLevel()

Gets the volume level of the early reflections.

int getReverbDelay()

Gets the reverb delay.

short getReverbLevel()

Gets the reverb level.

short getRoomHFLevel()

Gets the room HF level.

short getRoomLevel()

Gets the master volume level of the environmental reverb effect.

void setDecayHFRatio(short decayHFRatio)

Sets the ratio of high frequency decay time (at 5 kHz) relative to the decay time at low frequencies.

void setDecayTime(int decayTime)

Sets the time taken for the level of reverberation to decay by 60 dB.

void setDensity(short density)

Controls the modal density of the late reverberation decay.

void setDiffusion(short diffusion)

Sets the echo density in the late reverberation decay.

void setParameterListener(EnvironmentalReverb.OnParameterChangeListener listener)

Registers an OnParameterChangeListener interface.

void setProperties(EnvironmentalReverb.Settings settings)

Sets the environmental reverb properties.

void setReflectionsDelay(int reflectionsDelay)

Sets the delay time for the early reflections.

void setReflectionsLevel(short reflectionsLevel)

Sets the volume level of the early reflections.

void setReverbDelay(int reverbDelay)

Sets the time between the first reflection and the reverberation.

void setReverbLevel(short reverbLevel)

Sets the volume level of the late reverberation.

void setRoomHFLevel(short roomHF)

Sets the volume level at 5 kHz relative to the volume level at low frequencies of the overall reverb effect.

void setRoomLevel(short room)

Sets the master volume level of the environmental reverb effect.

Inherited methods

Constants

PARAM_DECAY_HF_RATIO

Added in API level 9
public static final int PARAM_DECAY_HF_RATIO

Decay HF ratio. Parameter ID for EnvironmentalReverb.OnParameterChangeListener

Constant Value: 3 (0x00000003)

PARAM_DECAY_TIME

Added in API level 9
public static final int PARAM_DECAY_TIME

Decay time. Parameter ID for OnParameterChangeListener

Constant Value: 2 (0x00000002)

PARAM_DENSITY

Added in API level 9
public static final int PARAM_DENSITY

Density. Parameter ID for OnParameterChangeListener

Constant Value: 9 (0x00000009)

PARAM_DIFFUSION

Added in API level 9
public static final int PARAM_DIFFUSION

Diffusion. Parameter ID for OnParameterChangeListener

Constant Value: 8 (0x00000008)

PARAM_REFLECTIONS_DELAY

Added in API level 9
public static final int PARAM_REFLECTIONS_DELAY

Early reflections delay. Parameter ID for OnParameterChangeListener

Constant Value: 5 (0x00000005)

PARAM_REFLECTIONS_LEVEL

Added in API level 9
public static final int PARAM_REFLECTIONS_LEVEL

Early reflections level. Parameter ID for OnParameterChangeListener

Constant Value: 4 (0x00000004)

PARAM_REVERB_DELAY

Added in API level 9
public static final int PARAM_REVERB_DELAY

Reverb delay. Parameter ID for OnParameterChangeListener

Constant Value: 7 (0x00000007)

PARAM_REVERB_LEVEL

Added in API level 9
public static final int PARAM_REVERB_LEVEL

Reverb level. Parameter ID for OnParameterChangeListener

Constant Value: 6 (0x00000006)

PARAM_ROOM_HF_LEVEL

Added in API level 9
public static final int PARAM_ROOM_HF_LEVEL

Room HF level. Parameter ID for OnParameterChangeListener

Constant Value: 1 (0x00000001)

PARAM_ROOM_LEVEL

Added in API level 9
public static final int PARAM_ROOM_LEVEL

Room level. Parameter ID for OnParameterChangeListener

Constant Value: 0 (0x00000000)

Public constructors

EnvironmentalReverb

Added in API level 9
public EnvironmentalReverb (int priority, 
                int audioSession)

Class constructor.

Parameters
priority int: the priority level requested by the application for controlling the EnvironmentalReverb 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 int: system wide unique audio session identifier. If audioSession is not 0, the EnvironmentalReverb will be attached to the MediaPlayer or AudioTrack in the same audio session. Otherwise, the EnvironmentalReverb will apply to the output mix. As the EnvironmentalReverb 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
java.lang.RuntimeException
IllegalArgumentException
RuntimeException
UnsupportedOperationException

Public methods

getDecayHFRatio

Added in API level 9
public short getDecayHFRatio ()

Gets the ratio of high frequency decay time (at 5 kHz) relative to low frequencies.

Returns
short the decay HF ration. See setDecayHFRatio(short) for units.

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

getDecayTime

Added in API level 9
public int getDecayTime ()

Gets the decay time.

Returns
int the decay time in milliseconds.

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

getDensity

Added in API level 9
public short getDensity ()

Gets the density level.

Returns
short the density level. See setDiffusion(short) for units.

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

getDiffusion

Added in API level 9
public short getDiffusion ()

Gets diffusion level.

Returns
short the diffusion level. See setDiffusion(short) for units.

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

getProperties

Added in API level 9
public EnvironmentalReverb.Settings getProperties ()

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

Returns
EnvironmentalReverb.Settings an EnvironmentalReverb.Settings object containing all current parameters values

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

getReflectionsDelay

Added in API level 9
public int getReflectionsDelay ()

Gets the reflections delay.

Returns
int the early reflections delay in milliseconds.

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

getReflectionsLevel

Added in API level 9
public short getReflectionsLevel ()

Gets the volume level of the early reflections.

Returns
short the early reflections level in millibels.

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

getReverbDelay

Added in API level 9
public int getReverbDelay ()

Gets the reverb delay.

Returns
int the reverb delay in milliseconds.

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

getReverbLevel

Added in API level 9
public short getReverbLevel ()

Gets the reverb level.

Returns
short the reverb level in millibels.

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

getRoomHFLevel

Added in API level 9
public short getRoomHFLevel ()

Gets the room HF level.

Returns
short the room HF level in millibels.

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

getRoomLevel

Added in API level 9
public short getRoomLevel ()

Gets the master volume level of the environmental reverb effect.

Returns
short the room level in millibels.

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

setDecayHFRatio

Added in API level 9
public void setDecayHFRatio (short decayHFRatio)

Sets the ratio of high frequency decay time (at 5 kHz) relative to the decay time at low frequencies.

Parameters
decayHFRatio short: high frequency decay ratio using a permille scale. The valid range is [100, 2000]. A ratio of 1000 indicates that all frequencies decay at the same rate.

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

setDecayTime

Added in API level 9
public void setDecayTime (int decayTime)

Sets the time taken for the level of reverberation to decay by 60 dB.

Parameters
decayTime int: decay time in milliseconds. The valid range is [100, 20000].

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

setDensity

Added in API level 9
public void setDensity (short density)

Controls the modal density of the late reverberation decay.

The scale should approximately map linearly to the perceived change in reverberation. A lower density creates a hollow sound that is useful for simulating small reverberation spaces such as bathrooms.

Parameters
density short: density specified using a permille scale. The valid range is [0, 1000]. A value of 1000 o/oo indicates a natural sounding reverberation. Values below this level produce a more colored effect.

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

setDiffusion

Added in API level 9
public void setDiffusion (short diffusion)

Sets the echo density in the late reverberation decay.

The scale should approximately map linearly to the perceived change in reverberation.

Parameters
diffusion short: diffusion specified using a permille scale. The diffusion valid range is [0, 1000]. A value of 1000 o/oo indicates a smooth reverberation decay. Values below this level give a more grainy character.

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

setParameterListener

Added in API level 9
public void setParameterListener (EnvironmentalReverb.OnParameterChangeListener listener)

Registers an OnParameterChangeListener interface.

Parameters
listener EnvironmentalReverb.OnParameterChangeListener: OnParameterChangeListener interface registered

setProperties

Added in API level 9
public void setProperties (EnvironmentalReverb.Settings settings)

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

Parameters
settings EnvironmentalReverb.Settings: a EnvironmentalReverb.Settings object containing the properties to apply

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

setReflectionsDelay

Added in API level 9
public void setReflectionsDelay (int reflectionsDelay)

Sets the delay time for the early reflections.

This method sets the time between when the direct path is heard and when the first reflection is heard.

Parameters
reflectionsDelay int: reflections delay in milliseconds. The valid range is [0, 300].

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

setReflectionsLevel

Added in API level 9
public void setReflectionsLevel (short reflectionsLevel)

Sets the volume level of the early reflections.

This level is combined with the overall room level (set using setRoomLevel(short)).

Parameters
reflectionsLevel short: reflection level in millibels. The valid range is [-9000, 1000].

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

setReverbDelay

Added in API level 9
public void setReverbDelay (int reverbDelay)

Sets the time between the first reflection and the reverberation.

Parameters
reverbDelay int: reverb delay in milliseconds. The valid range is [0, 100].

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

setReverbLevel

Added in API level 9
public void setReverbLevel (short reverbLevel)

Sets the volume level of the late reverberation.

This level is combined with the overall room level (set using setRoomLevel(short)).

Parameters
reverbLevel short: reverb level in millibels. The valid range is [-9000, 2000].

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

setRoomHFLevel

Added in API level 9
public void setRoomHFLevel (short roomHF)

Sets the volume level at 5 kHz relative to the volume level at low frequencies of the overall reverb effect.

This controls a low-pass filter that will reduce the level of the high-frequency.

Parameters
roomHF short: high frequency attenuation level in millibels. The valid range is [-9000, 0].

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException

setRoomLevel

Added in API level 9
public void setRoomLevel (short room)

Sets the master volume level of the environmental reverb effect.

Parameters
room short: room level in millibels. The valid range is [-9000, 0].

Throws
java.lang.IllegalStateException
java.lang.IllegalArgumentException
java.lang.UnsupportedOperationException
IllegalArgumentException
IllegalStateException
UnsupportedOperationException