| java.lang.Object | |
| ↳ | android.media.audiofx.AudioEffect |
 Known Direct Subclasses
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AudioEffect is the base class for controlling audio effects provided by the android audio framework.
Applications should not use the AudioEffect class directly but one of its derived classes to control specific effects:
To apply the audio effect to a specific AudioTrack or MediaPlayer instance,
the application must specify the audio session ID of that instance when creating the AudioEffect.
(see getAudioSessionId() for details on audio sessions).
NOTE: attaching insert effects (equalizer, bass boost, virtualizer) to the global audio output mix by use of session 0 is deprecated.
Creating an AudioEffect object will create the corresponding effect engine in the audio framework if no instance of the same effect type exists in the specified audio session. If one exists, this instance will be used.
The application creating the AudioEffect object (or a derived class) will either receive control of the effect engine or not depending on the priority parameter. If priority is higher than the priority used by the current effect engine owner, the control will be transfered to the new object. Otherwise control will remain with the previous object. In this case, the new application will be notified of changes in effect engine state or control ownership by the appropiate listener.
| Nested Classes | |||||||||||
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| AudioEffect.Descriptor | The effect descriptor contains information on a particular effect implemented in the
audio framework:
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| AudioEffect.OnControlStatusChangeListener | The OnControlStatusChangeListener interface defines a method called by the AudioEffect when a the control of the effect engine is gained or lost by the application | ||||||||||
| AudioEffect.OnEnableStatusChangeListener | The OnEnableStatusChangeListener interface defines a method called by the AudioEffect when a the enabled state of the effect engine was changed by the controlling application. | ||||||||||
| Constants | |||||||||||
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| 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
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| int | CONTENT_TYPE_MOVIE | Value for EXTRA_CONTENT_TYPE when the type of content played is video or movie
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| int | CONTENT_TYPE_MUSIC | Value for EXTRA_CONTENT_TYPE when the type of content played is music
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| int | CONTENT_TYPE_VOICE | Value for EXTRA_CONTENT_TYPE when the type of content played is voice audio
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| String | EFFECT_AUXILIARY | Effect connection mode is auxiliary. | |||||||||
| String | EFFECT_INSERT | Effect connection mode is insert. | |||||||||
| 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. | |||||||||
| Fields | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| EFFECT_TYPE_AEC | UUID for Acoustic Echo Canceler (AEC) | ||||||||||
| EFFECT_TYPE_AGC | UUID for Automatic Gain Control (AGC) | ||||||||||
| EFFECT_TYPE_BASS_BOOST | UUID for bass boost effect | ||||||||||
| EFFECT_TYPE_ENV_REVERB | UUID for environmental reverberation effect | ||||||||||
| EFFECT_TYPE_EQUALIZER | UUID for equalizer effect | ||||||||||
| EFFECT_TYPE_LOUDNESS_ENHANCER | UUID for Loudness Enhancer | ||||||||||
| EFFECT_TYPE_NS | UUID for Noise Suppressor (NS) | ||||||||||
| EFFECT_TYPE_PRESET_REVERB | UUID for preset reverberation effect | ||||||||||
| EFFECT_TYPE_VIRTUALIZER | UUID for virtualizer effect | ||||||||||
| Public Methods | |||||||||||
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Get the effect descriptor.
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Returns effect enabled state
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Returns effect unique identifier.
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Checks if this AudioEffect object is controlling the effect engine.
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Query all effects available on the platform.
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Releases the native AudioEffect resources.
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Sets the listener AudioEffect notifies when the effect engine control is
taken or returned.
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Sets the listener AudioEffect notifies when the effect engine is enabled
or disabled.
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Enable or disable the effect.
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| Protected Methods | |||||||||||
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Invoked when the garbage collector has detected that this instance is no longer reachable.
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[Expand]
Inherited Methods | |||||||||||
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From class
java.lang.Object
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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.
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
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.
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.
Internal operation status. Not returned by any method.
Value for EXTRA_CONTENT_TYPE when the type of content played is game audio
Value for EXTRA_CONTENT_TYPE when the type of content played is video or movie
Value for EXTRA_CONTENT_TYPE when the type of content played is music
Value for EXTRA_CONTENT_TYPE when the type of content played is voice audio
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.
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.
Unspecified error.
Operation failed due to bad parameter value.
Operation failed due to dead remote object.
Operation failed because it was requested in wrong state.
Operation failed due to bad object initialization.
Operation failed due to lack of memory.
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.
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:
If omitted, the content type defaults toCONTENT_TYPE_MUSIC.
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.
Successful operation.
UUID for Acoustic Echo Canceler (AEC)
UUID for Automatic Gain Control (AGC)
UUID for environmental reverberation effect
UUID for Loudness Enhancer
UUID for preset reverberation effect
Returns effect enabled state
| IllegalStateException |
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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)
| IllegalStateException |
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Checks if this AudioEffect object is controlling the effect engine.
| IllegalStateException |
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Query all effects available on the platform. Returns an array of
AudioEffect.Descriptor objects
| IllegalStateException |
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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.
Sets the listener AudioEffect notifies when the effect engine control is taken or returned.
Sets the listener AudioEffect notifies when the effect engine is enabled or disabled.
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.
| enabled | the requested enable state |
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SUCCESS in case of success, ERROR_INVALID_OPERATION
or ERROR_DEAD_OBJECT in case of failure.| IllegalStateException |
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Invoked when the garbage collector has detected that this instance is no longer reachable. The default implementation does nothing, but this method can be overridden to free resources.
Note that objects that override finalize are significantly more expensive than
objects that don't. Finalizers may be run a long time after the object is no longer
reachable, depending on memory pressure, so it's a bad idea to rely on them for cleanup.
Note also that finalizers are run on a single VM-wide finalizer thread,
so doing blocking work in a finalizer is a bad idea. A finalizer is usually only necessary
for a class that has a native peer and needs to call a native method to destroy that peer.
Even then, it's better to provide an explicit close method (and implement
Closeable), and insist that callers manually dispose of instances. This
works well for something like files, but less well for something like a BigInteger
where typical calling code would have to deal with lots of temporaries. Unfortunately,
code that creates lots of temporaries is the worst kind of code from the point of view of
the single finalizer thread.
If you must use finalizers, consider at least providing your own
ReferenceQueue and having your own thread process that queue.
Unlike constructors, finalizers are not automatically chained. You are responsible for
calling super.finalize() yourself.
Uncaught exceptions thrown by finalizers are ignored and do not terminate the finalizer thread. See Effective Java Item 7, "Avoid finalizers" for more.