/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.media.audiofx;
import android.media.audiofx.AudioEffect;
import java.util.StringTokenizer;
/**
* 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
* {@link android.media.audiofx.EnvironmentalReverb} class.
* <p>An application creates a PresetReverb object to instantiate and control a reverb engine in the
* audio framework.
* <p>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.
* <p>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.
* <p>Creating a reverb on the output mix (audio session 0) requires permission
* {@link android.Manifest.permission#MODIFY_AUDIO_SETTINGS}
* <p>See {@link android.media.audiofx.AudioEffect} class for more details on controlling
* audio effects.
*/
public class PresetReverb extends AudioEffect {
private final static String TAG = "PresetReverb";
// These constants must be synchronized with those in
// frameworks/base/include/media/EffectPresetReverbApi.h
/**
* Preset. Parameter ID for
* {@link android.media.audiofx.PresetReverb.OnParameterChangeListener}
*/
public static final int PARAM_PRESET = 0;
/**
* No reverb or reflections
*/
public static final short PRESET_NONE = 0;
/**
* Reverb preset representing a small room less than five meters in length
*/
public static final short PRESET_SMALLROOM = 1;
/**
* Reverb preset representing a medium room with a length of ten meters or less
*/
public static final short PRESET_MEDIUMROOM = 2;
/**
* Reverb preset representing a large-sized room suitable for live performances
*/
public static final short PRESET_LARGEROOM = 3;
/**
* Reverb preset representing a medium-sized hall
*/
public static final short PRESET_MEDIUMHALL = 4;
/**
* Reverb preset representing a large-sized hall suitable for a full orchestra
*/
public static final short PRESET_LARGEHALL = 5;
/**
* Reverb preset representing a synthesis of the traditional plate reverb
*/
public static final short PRESET_PLATE = 6;
/**
* Registered listener for parameter changes.
*/
private OnParameterChangeListener mParamListener = null;
/**
* Listener used internally to to receive raw parameter change event from AudioEffect super class
*/
private BaseParameterListener mBaseParamListener = null;
/**
* Lock for access to mParamListener
*/
private final Object mParamListenerLock = new Object();
/**
* Class constructor.
* @param 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.
* @param 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
* @throws java.lang.UnsupportedOperationException
* @throws java.lang.RuntimeException
*/
public PresetReverb(int priority, int audioSession)
throws IllegalArgumentException, UnsupportedOperationException, RuntimeException {
super(EFFECT_TYPE_PRESET_REVERB, EFFECT_TYPE_NULL, priority, audioSession);
}
/**
* Enables a preset on the reverb.
* <p>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.
* @param preset this must be one of the the preset constants defined in this class.
* e.g. {@link #PRESET_SMALLROOM}
* @throws IllegalStateException
* @throws IllegalArgumentException
* @throws UnsupportedOperationException
*/
public void setPreset(short preset)
throws IllegalStateException, IllegalArgumentException, UnsupportedOperationException {
checkStatus(setParameter(PARAM_PRESET, preset));
}
/**
* Gets current reverb preset.
* @return the preset that is set at the moment.
* @throws IllegalStateException
* @throws IllegalArgumentException
* @throws UnsupportedOperationException
*/
public short getPreset()
throws IllegalStateException, IllegalArgumentException, UnsupportedOperationException {
short[] value = new short[1];
checkStatus(getParameter(PARAM_PRESET, value));
return value[0];
}
/**
* The OnParameterChangeListener interface defines a method called by the PresetReverb
* when a parameter value has changed.
*/
public interface OnParameterChangeListener {
/**
* Method called when a parameter value has changed. The method is called only if the
* parameter was changed by another application having the control of the same
* PresetReverb engine.
* @param effect the PresetReverb on which the interface is registered.
* @param status status of the set parameter operation.
* @param param ID of the modified parameter. See {@link #PARAM_PRESET} ...
* @param value the new parameter value.
*/
void onParameterChange(PresetReverb effect, int status, int param, short value);
}
/**
* Listener used internally to receive unformatted parameter change events from AudioEffect
* super class.
*/
private class BaseParameterListener implements AudioEffect.OnParameterChangeListener {
private BaseParameterListener() {
}
public void onParameterChange(AudioEffect effect, int status, byte[] param, byte[] value) {
OnParameterChangeListener l = null;
synchronized (mParamListenerLock) {
if (mParamListener != null) {
l = mParamListener;
}
}
if (l != null) {
int p = -1;
short v = -1;
if (param.length == 4) {
p = byteArrayToInt(param, 0);
}
if (value.length == 2) {
v = byteArrayToShort(value, 0);
}
if (p != -1 && v != -1) {
l.onParameterChange(PresetReverb.this, status, p, v);
}
}
}
}
/**
* Registers an OnParameterChangeListener interface.
* @param listener OnParameterChangeListener interface registered
*/
public void setParameterListener(OnParameterChangeListener listener) {
synchronized (mParamListenerLock) {
if (mParamListener == null) {
mParamListener = listener;
mBaseParamListener = new BaseParameterListener();
super.setParameterListener(mBaseParamListener);
}
}
}
/**
* The Settings class regroups all preset reverb parameters. It is used in
* conjuntion with getProperties() and setProperties() methods to backup and restore
* all parameters in a single call.
*/
public static class Settings {
public short preset;
public Settings() {
}
/**
* Settings class constructor from a key=value; pairs formatted string. The string is
* typically returned by Settings.toString() method.
* @throws IllegalArgumentException if the string is not correctly formatted.
*/
public Settings(String settings) {
StringTokenizer st = new StringTokenizer(settings, "=;");
int tokens = st.countTokens();
if (st.countTokens() != 3) {
throw new IllegalArgumentException("settings: " + settings);
}
String key = st.nextToken();
if (!key.equals("PresetReverb")) {
throw new IllegalArgumentException(
"invalid settings for PresetReverb: " + key);
}
try {
key = st.nextToken();
if (!key.equals("preset")) {
throw new IllegalArgumentException("invalid key name: " + key);
}
preset = Short.parseShort(st.nextToken());
} catch (NumberFormatException nfe) {
throw new IllegalArgumentException("invalid value for key: " + key);
}
}
@Override
public String toString() {
String str = new String (
"PresetReverb"+
";preset="+Short.toString(preset)
);
return str;
}
};
/**
* Gets the preset reverb properties. This method is useful when a snapshot of current
* preset reverb settings must be saved by the application.
* @return a PresetReverb.Settings object containing all current parameters values
* @throws IllegalStateException
* @throws IllegalArgumentException
* @throws UnsupportedOperationException
*/
public PresetReverb.Settings getProperties()
throws IllegalStateException, IllegalArgumentException, UnsupportedOperationException {
Settings settings = new Settings();
short[] value = new short[1];
checkStatus(getParameter(PARAM_PRESET, value));
settings.preset = value[0];
return settings;
}
/**
* Sets the preset reverb properties. This method is useful when preset reverb settings have to
* be applied from a previous backup.
* @param settings a PresetReverb.Settings object containing the properties to apply
* @throws IllegalStateException
* @throws IllegalArgumentException
* @throws UnsupportedOperationException
*/
public void setProperties(PresetReverb.Settings settings)
throws IllegalStateException, IllegalArgumentException, UnsupportedOperationException {
checkStatus(setParameter(PARAM_PRESET, settings.preset));
}
}