/*
* 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.util.Log;
import java.lang.ref.WeakReference;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
/**
* The Visualizer class enables application to retrieve part of the currently playing audio for
* visualization purpose. It is not an audio recording interface and only returns partial and low
* quality audio content. However, to protect privacy of certain audio data (e.g voice mail) the use
* of the visualizer requires the permission android.permission.RECORD_AUDIO.
* <p>The audio session ID passed to the constructor indicates which audio content should be
* visualized:<br>
* <ul>
* <li>If the session is 0, the audio output mix is visualized</li>
* <li>If the session is not 0, the audio from a particular {@link android.media.MediaPlayer} or
* {@link android.media.AudioTrack}
* using this audio session is visualized </li>
* </ul>
* <p>Two types of representation of audio content can be captured: <br>
* <ul>
* <li>Waveform data: consecutive 8-bit (unsigned) mono samples by using the
* {@link #getWaveForm(byte[])} method</li>
* <li>Frequency data: 8-bit magnitude FFT by using the {@link #getFft(byte[])} method</li>
* </ul>
* <p>The length of the capture can be retrieved or specified by calling respectively
* {@link #getCaptureSize()} and {@link #setCaptureSize(int)} methods. The capture size must be a
* power of 2 in the range returned by {@link #getCaptureSizeRange()}.
* <p>In addition to the polling capture mode described above with {@link #getWaveForm(byte[])} and
* {@link #getFft(byte[])} methods, a callback mode is also available by installing a listener by
* use of the {@link #setDataCaptureListener(OnDataCaptureListener, int, boolean, boolean)} method.
* The rate at which the listener capture method is called as well as the type of data returned is
* specified.
* <p>Before capturing data, the Visualizer must be enabled by calling the
* {@link #setEnabled(boolean)} method.
* When data capture is not needed any more, the Visualizer should be disabled.
* <p>It is good practice to call the {@link #release()} method when the Visualizer is not used
* anymore to free up native resources associated to the Visualizer instance.
* <p>Creating a Visualizer on the output mix (audio session 0) requires permission
* {@link android.Manifest.permission#MODIFY_AUDIO_SETTINGS}
* <p>The Visualizer class can also be used to perform measurements on the audio being played back.
* The measurements to perform are defined by setting a mask of the requested measurement modes with
* {@link #setMeasurementMode(int)}. Supported values are {@link #MEASUREMENT_MODE_NONE} to cancel
* any measurement, and {@link #MEASUREMENT_MODE_PEAK_RMS} for peak and RMS monitoring.
* Measurements can be retrieved through {@link #getMeasurementPeakRms(MeasurementPeakRms)}.
*/
public class Visualizer {
static {
System.loadLibrary("audioeffect_jni");
native_init();
}
private final static String TAG = "Visualizer-JAVA";
/**
* State of a Visualizer object that was not successfully initialized upon creation
*/
public static final int STATE_UNINITIALIZED = 0;
/**
* State of a Visualizer object that is ready to be used.
*/
public static final int STATE_INITIALIZED = 1;
/**
* State of a Visualizer object that is active.
*/
public static final int STATE_ENABLED = 2;
// to keep in sync with system/media/audio_effects/include/audio_effects/effect_visualizer.h
/**
* Defines a capture mode where amplification is applied based on the content of the captured
* data. This is the default Visualizer mode, and is suitable for music visualization.
*/
public static final int SCALING_MODE_NORMALIZED = 0;
/**
* Defines a capture mode where the playback volume will affect (scale) the range of the
* captured data. A low playback volume will lead to low sample and fft values, and vice-versa.
*/
public static final int SCALING_MODE_AS_PLAYED = 1;
/**
* Defines a measurement mode in which no measurements are performed.
*/
public static final int MEASUREMENT_MODE_NONE = 0;
/**
* Defines a measurement mode which computes the peak and RMS value in mB, where 0mB is the
* maximum sample value, and -9600mB is the minimum value.
* Values for peak and RMS can be retrieved with
* {@link #getMeasurementPeakRms(MeasurementPeakRms)}.
*/
public static final int MEASUREMENT_MODE_PEAK_RMS = 1 << 0;
// to keep in sync with frameworks/base/media/jni/audioeffect/android_media_Visualizer.cpp
private static final int NATIVE_EVENT_PCM_CAPTURE = 0;
private static final int NATIVE_EVENT_FFT_CAPTURE = 1;
private static final int NATIVE_EVENT_SERVER_DIED = 2;
// Error codes:
/**
* Successful operation.
*/
public static final int SUCCESS = 0;
/**
* Unspecified error.
*/
public static final int ERROR = -1;
/**
* Internal operation status. Not returned by any method.
*/
public static final int ALREADY_EXISTS = -2;
/**
* Operation failed due to bad object initialization.
*/
public static final int ERROR_NO_INIT = -3;
/**
* Operation failed due to bad parameter value.
*/
public static final int ERROR_BAD_VALUE = -4;
/**
* Operation failed because it was requested in wrong state.
*/
public static final int ERROR_INVALID_OPERATION = -5;
/**
* Operation failed due to lack of memory.
*/
public static final int ERROR_NO_MEMORY = -6;
/**
* Operation failed due to dead remote object.
*/
public static final int ERROR_DEAD_OBJECT = -7;
//--------------------------------------------------------------------------
// Member variables
//--------------------
/**
* Indicates the state of the Visualizer instance
*/
private int mState = STATE_UNINITIALIZED;
/**
* Lock to synchronize access to mState
*/
private final Object mStateLock = new Object();
/**
* System wide unique Identifier of the visualizer engine used by this Visualizer instance
*/
private int mId;
/**
* Lock to protect listeners updates against event notifications
*/
private final Object mListenerLock = new Object();
/**
* Handler for events coming from the native code
*/
private NativeEventHandler mNativeEventHandler = null;
/**
* PCM and FFT capture listener registered by client
*/
private OnDataCaptureListener mCaptureListener = null;
/**
* Server Died listener registered by client
*/
private OnServerDiedListener mServerDiedListener = null;
// accessed by native methods
private long mNativeVisualizer;
private long mJniData;
//--------------------------------------------------------------------------
// Constructor, Finalize
//--------------------
/**
* Class constructor.
* @param audioSession system wide unique audio session identifier. If audioSession
* is not 0, the visualizer will be attached to the MediaPlayer or AudioTrack in the
* same audio session. Otherwise, the Visualizer will apply to the output mix.
*
* @throws java.lang.UnsupportedOperationException
* @throws java.lang.RuntimeException
*/
public Visualizer(int audioSession)
throws UnsupportedOperationException, RuntimeException {
int[] id = new int[1];
synchronized (mStateLock) {
mState = STATE_UNINITIALIZED;
// native initialization
int result = native_setup(new WeakReference<Visualizer>(this), audioSession, id);
if (result != SUCCESS && result != ALREADY_EXISTS) {
Log.e(TAG, "Error code "+result+" when initializing Visualizer.");
switch (result) {
case ERROR_INVALID_OPERATION:
throw (new UnsupportedOperationException("Effect library not loaded"));
default:
throw (new RuntimeException("Cannot initialize Visualizer engine, error: "
+result));
}
}
mId = id[0];
if (native_getEnabled()) {
mState = STATE_ENABLED;
} else {
mState = STATE_INITIALIZED;
}
}
}
/**
* Releases the native Visualizer resources. It is a good practice to release the
* visualization engine when not in use.
*/
public void release() {
synchronized (mStateLock) {
native_release();
mState = STATE_UNINITIALIZED;
}
}
@Override
protected void finalize() {
native_finalize();
}
/**
* Enable or disable the visualization engine.
* @param enabled requested enable state
* @return {@link #SUCCESS} in case of success,
* {@link #ERROR_INVALID_OPERATION} or {@link #ERROR_DEAD_OBJECT} in case of failure.
* @throws IllegalStateException
*/
public int setEnabled(boolean enabled)
throws IllegalStateException {
synchronized (mStateLock) {
if (mState == STATE_UNINITIALIZED) {
throw(new IllegalStateException("setEnabled() called in wrong state: "+mState));
}
int status = SUCCESS;
if ((enabled && (mState == STATE_INITIALIZED)) ||
(!enabled && (mState == STATE_ENABLED))) {
status = native_setEnabled(enabled);
if (status == SUCCESS) {
mState = enabled ? STATE_ENABLED : STATE_INITIALIZED;
}
}
return status;
}
}
/**
* Get current activation state of the visualizer.
* @return true if the visualizer is active, false otherwise
*/
public boolean getEnabled()
{
synchronized (mStateLock) {
if (mState == STATE_UNINITIALIZED) {
throw(new IllegalStateException("getEnabled() called in wrong state: "+mState));
}
return native_getEnabled();
}
}
/**
* Returns the capture size range.
* @return the mininum capture size is returned in first array element and the maximum in second
* array element.
*/
public static native int[] getCaptureSizeRange();
/**
* Returns the maximum capture rate for the callback capture method. This is the maximum value
* for the rate parameter of the
* {@link #setDataCaptureListener(OnDataCaptureListener, int, boolean, boolean)} method.
* @return the maximum capture rate expressed in milliHertz
*/
public static native int getMaxCaptureRate();
/**
* Sets the capture size, i.e. the number of bytes returned by {@link #getWaveForm(byte[])} and
* {@link #getFft(byte[])} methods. The capture size must be a power of 2 in the range returned
* by {@link #getCaptureSizeRange()}.
* This method must not be called when the Visualizer is enabled.
* @param size requested capture size
* @return {@link #SUCCESS} in case of success,
* {@link #ERROR_BAD_VALUE} in case of failure.
* @throws IllegalStateException
*/
public int setCaptureSize(int size)
throws IllegalStateException {
synchronized (mStateLock) {
if (mState != STATE_INITIALIZED) {
throw(new IllegalStateException("setCaptureSize() called in wrong state: "+mState));
}
return native_setCaptureSize(size);
}
}
/**
* Returns current capture size.
* @return the capture size in bytes.
*/
public int getCaptureSize()
throws IllegalStateException {
synchronized (mStateLock) {
if (mState == STATE_UNINITIALIZED) {
throw(new IllegalStateException("getCaptureSize() called in wrong state: "+mState));
}
return native_getCaptureSize();
}
}
/**
* Set the type of scaling applied on the captured visualization data.
* @param mode see {@link #SCALING_MODE_NORMALIZED}
* and {@link #SCALING_MODE_AS_PLAYED}
* @return {@link #SUCCESS} in case of success,
* {@link #ERROR_BAD_VALUE} in case of failure.
* @throws IllegalStateException
*/
public int setScalingMode(int mode)
throws IllegalStateException {
synchronized (mStateLock) {
if (mState == STATE_UNINITIALIZED) {
throw(new IllegalStateException("setScalingMode() called in wrong state: "
+ mState));
}
return native_setScalingMode(mode);
}
}
/**
* Returns the current scaling mode on the captured visualization data.
* @return the scaling mode, see {@link #SCALING_MODE_NORMALIZED}
* and {@link #SCALING_MODE_AS_PLAYED}.
* @throws IllegalStateException
*/
public int getScalingMode()
throws IllegalStateException {
synchronized (mStateLock) {
if (mState == STATE_UNINITIALIZED) {
throw(new IllegalStateException("getScalingMode() called in wrong state: "
+ mState));
}
return native_getScalingMode();
}
}
/**
* Sets the combination of measurement modes to be performed by this audio effect.
* @param mode a mask of the measurements to perform. The valid values are
* {@link #MEASUREMENT_MODE_NONE} (to cancel any measurement)
* or {@link #MEASUREMENT_MODE_PEAK_RMS}.
* @return {@link #SUCCESS} in case of success, {@link #ERROR_BAD_VALUE} in case of failure.
* @throws IllegalStateException
*/
public int setMeasurementMode(int mode)
throws IllegalStateException {
synchronized (mStateLock) {
if (mState == STATE_UNINITIALIZED) {
throw(new IllegalStateException("setMeasurementMode() called in wrong state: "
+ mState));
}
return native_setMeasurementMode(mode);
}
}
/**
* Returns the current measurement modes performed by this audio effect
* @return the mask of the measurements,
* {@link #MEASUREMENT_MODE_NONE} (when no measurements are performed)
* or {@link #MEASUREMENT_MODE_PEAK_RMS}.
* @throws IllegalStateException
*/
public int getMeasurementMode()
throws IllegalStateException {
synchronized (mStateLock) {
if (mState == STATE_UNINITIALIZED) {
throw(new IllegalStateException("getMeasurementMode() called in wrong state: "
+ mState));
}
return native_getMeasurementMode();
}
}
/**
* Returns the sampling rate of the captured audio.
* @return the sampling rate in milliHertz.
*/
public int getSamplingRate()
throws IllegalStateException {
synchronized (mStateLock) {
if (mState == STATE_UNINITIALIZED) {
throw(new IllegalStateException("getSamplingRate() called in wrong state: "+mState));
}
return native_getSamplingRate();
}
}
/**
* Returns a waveform capture of currently playing audio content. The capture consists in
* a number of consecutive 8-bit (unsigned) mono PCM samples equal to the capture size returned
* by {@link #getCaptureSize()}.
* <p>This method must be called when the Visualizer is enabled.
* @param waveform array of bytes where the waveform should be returned
* @return {@link #SUCCESS} in case of success,
* {@link #ERROR_NO_MEMORY}, {@link #ERROR_INVALID_OPERATION} or {@link #ERROR_DEAD_OBJECT}
* in case of failure.
* @throws IllegalStateException
*/
public int getWaveForm(byte[] waveform)
throws IllegalStateException {
synchronized (mStateLock) {
if (mState != STATE_ENABLED) {
throw(new IllegalStateException("getWaveForm() called in wrong state: "+mState));
}
return native_getWaveForm(waveform);
}
}
/**
* Returns a frequency capture of currently playing audio content.
* <p>This method must be called when the Visualizer is enabled.
* <p>The capture is an 8-bit magnitude FFT, the frequency range covered being 0 (DC) to half of
* the sampling rate returned by {@link #getSamplingRate()}. The capture returns the real and
* imaginary parts of a number of frequency points equal to half of the capture size plus one.
* <p>Note: only the real part is returned for the first point (DC) and the last point
* (sampling frequency / 2).
* <p>The layout in the returned byte array is as follows:
* <ul>
* <li> n is the capture size returned by getCaptureSize()</li>
* <li> Rfk, Ifk are respectively the real and imaginary parts of the kth frequency
* component</li>
* <li> If Fs is the sampling frequency retuned by getSamplingRate() the kth frequency is:
* (k*Fs)/(n/2) </li>
* </ul>
* <table border="0" cellspacing="0" cellpadding="0">
* <tr><td>Index </p></td>
* <td>0 </p></td>
* <td>1 </p></td>
* <td>2 </p></td>
* <td>3 </p></td>
* <td>4 </p></td>
* <td>5 </p></td>
* <td>... </p></td>
* <td>n - 2 </p></td>
* <td>n - 1 </p></td></tr>
* <tr><td>Data </p></td>
* <td>Rf0 </p></td>
* <td>Rf(n/2) </p></td>
* <td>Rf1 </p></td>
* <td>If1 </p></td>
* <td>Rf2 </p></td>
* <td>If2 </p></td>
* <td>... </p></td>
* <td>Rf(n-1)/2 </p></td>
* <td>If(n-1)/2 </p></td></tr>
* </table>
* @param fft array of bytes where the FFT should be returned
* @return {@link #SUCCESS} in case of success,
* {@link #ERROR_NO_MEMORY}, {@link #ERROR_INVALID_OPERATION} or {@link #ERROR_DEAD_OBJECT}
* in case of failure.
* @throws IllegalStateException
*/
public int getFft(byte[] fft)
throws IllegalStateException {
synchronized (mStateLock) {
if (mState != STATE_ENABLED) {
throw(new IllegalStateException("getFft() called in wrong state: "+mState));
}
return native_getFft(fft);
}
}
/**
* A class to store peak and RMS values.
* Peak and RMS are expressed in mB, as described in the
* {@link Visualizer#MEASUREMENT_MODE_PEAK_RMS} measurement mode.
*/
public static final class MeasurementPeakRms {
/**
* The peak value in mB.
*/
public int mPeak;
/**
* The RMS value in mB.
*/
public int mRms;
}
/**
* Retrieves the latest peak and RMS measurement.
* Sets the peak and RMS fields of the supplied {@link Visualizer.MeasurementPeakRms} to the
* latest measured values.
* @param measurement a non-null {@link Visualizer.MeasurementPeakRms} instance to store
* the measurement values.
* @return {@link #SUCCESS} in case of success, {@link #ERROR_BAD_VALUE},
* {@link #ERROR_NO_MEMORY}, {@link #ERROR_INVALID_OPERATION} or {@link #ERROR_DEAD_OBJECT}
* in case of failure.
*/
public int getMeasurementPeakRms(MeasurementPeakRms measurement) {
if (measurement == null) {
Log.e(TAG, "Cannot store measurements in a null object");
return ERROR_BAD_VALUE;
}
synchronized (mStateLock) {
if (mState != STATE_ENABLED) {
throw (new IllegalStateException("getMeasurementPeakRms() called in wrong state: "
+ mState));
}
return native_getPeakRms(measurement);
}
}
//---------------------------------------------------------
// Interface definitions
//--------------------
/**
* The OnDataCaptureListener interface defines methods called by the Visualizer to periodically
* update the audio visualization capture.
* The client application can implement this interface and register the listener with the
* {@link #setDataCaptureListener(OnDataCaptureListener, int, boolean, boolean)} method.
*/
public interface OnDataCaptureListener {
/**
* Method called when a new waveform capture is available.
* <p>Data in the waveform buffer is valid only within the scope of the callback.
* Applications which needs access to the waveform data after returning from the callback
* should make a copy of the data instead of holding a reference.
* @param visualizer Visualizer object on which the listener is registered.
* @param waveform array of bytes containing the waveform representation.
* @param samplingRate sampling rate of the audio visualized.
*/
void onWaveFormDataCapture(Visualizer visualizer, byte[] waveform, int samplingRate);
/**
* Method called when a new frequency capture is available.
* <p>Data in the fft buffer is valid only within the scope of the callback.
* Applications which needs access to the fft data after returning from the callback
* should make a copy of the data instead of holding a reference.
* @param visualizer Visualizer object on which the listener is registered.
* @param fft array of bytes containing the frequency representation.
* @param samplingRate sampling rate of the audio visualized.
*/
void onFftDataCapture(Visualizer visualizer, byte[] fft, int samplingRate);
}
/**
* Registers an OnDataCaptureListener interface and specifies the rate at which the capture
* should be updated as well as the type of capture requested.
* <p>Call this method with a null listener to stop receiving the capture updates.
* @param listener OnDataCaptureListener registered
* @param rate rate in milliHertz at which the capture should be updated
* @param waveform true if a waveform capture is requested: the onWaveFormDataCapture()
* method will be called on the OnDataCaptureListener interface.
* @param fft true if a frequency capture is requested: the onFftDataCapture() method will be
* called on the OnDataCaptureListener interface.
* @return {@link #SUCCESS} in case of success,
* {@link #ERROR_NO_INIT} or {@link #ERROR_BAD_VALUE} in case of failure.
*/
public int setDataCaptureListener(OnDataCaptureListener listener,
int rate, boolean waveform, boolean fft) {
synchronized (mListenerLock) {
mCaptureListener = listener;
}
if (listener == null) {
// make sure capture callback is stopped in native code
waveform = false;
fft = false;
}
int status = native_setPeriodicCapture(rate, waveform, fft);
if (status == SUCCESS) {
if ((listener != null) && (mNativeEventHandler == null)) {
Looper looper;
if ((looper = Looper.myLooper()) != null) {
mNativeEventHandler = new NativeEventHandler(this, looper);
} else if ((looper = Looper.getMainLooper()) != null) {
mNativeEventHandler = new NativeEventHandler(this, looper);
} else {
mNativeEventHandler = null;
status = ERROR_NO_INIT;
}
}
}
return status;
}
/**
* @hide
*
* The OnServerDiedListener interface defines a method called by the Visualizer to indicate that
* the connection to the native media server has been broken and that the Visualizer object will
* need to be released and re-created.
* The client application can implement this interface and register the listener with the
* {@link #setServerDiedListener(OnServerDiedListener)} method.
*/
public interface OnServerDiedListener {
/**
* @hide
*
* Method called when the native media server has died.
* <p>If the native media server encounters a fatal error and needs to restart, the binder
* connection from the {@link #Visualizer} to the media server will be broken. Data capture
* callbacks will stop happening, and client initiated calls to the {@link #Visualizer}
* instance will fail with the error code {@link #DEAD_OBJECT}. To restore functionality,
* clients should {@link #release()} their old visualizer and create a new instance.
*/
void onServerDied();
}
/**
* @hide
*
* Registers an OnServerDiedListener interface.
* <p>Call this method with a null listener to stop receiving server death notifications.
* @return {@link #SUCCESS} in case of success,
*/
public int setServerDiedListener(OnServerDiedListener listener) {
synchronized (mListenerLock) {
mServerDiedListener = listener;
}
return SUCCESS;
}
/**
* Helper class to handle the forwarding of native events to the appropriate listeners
*/
private class NativeEventHandler extends Handler
{
private Visualizer mVisualizer;
public NativeEventHandler(Visualizer v, Looper looper) {
super(looper);
mVisualizer = v;
}
private void handleCaptureMessage(Message msg) {
OnDataCaptureListener l = null;
synchronized (mListenerLock) {
l = mVisualizer.mCaptureListener;
}
if (l != null) {
byte[] data = (byte[])msg.obj;
int samplingRate = msg.arg1;
switch(msg.what) {
case NATIVE_EVENT_PCM_CAPTURE:
l.onWaveFormDataCapture(mVisualizer, data, samplingRate);
break;
case NATIVE_EVENT_FFT_CAPTURE:
l.onFftDataCapture(mVisualizer, data, samplingRate);
break;
default:
Log.e(TAG,"Unknown native event in handleCaptureMessge: "+msg.what);
break;
}
}
}
private void handleServerDiedMessage(Message msg) {
OnServerDiedListener l = null;
synchronized (mListenerLock) {
l = mVisualizer.mServerDiedListener;
}
if (l != null)
l.onServerDied();
}
@Override
public void handleMessage(Message msg) {
if (mVisualizer == null) {
return;
}
switch(msg.what) {
case NATIVE_EVENT_PCM_CAPTURE:
case NATIVE_EVENT_FFT_CAPTURE:
handleCaptureMessage(msg);
break;
case NATIVE_EVENT_SERVER_DIED:
handleServerDiedMessage(msg);
break;
default:
Log.e(TAG,"Unknown native event: "+msg.what);
break;
}
}
}
//---------------------------------------------------------
// Interface definitions
//--------------------
private static native final void native_init();
private native final int native_setup(Object audioeffect_this,
int audioSession,
int[] id);
private native final void native_finalize();
private native final void native_release();
private native final int native_setEnabled(boolean enabled);
private native final boolean native_getEnabled();
private native final int native_setCaptureSize(int size);
private native final int native_getCaptureSize();
private native final int native_setScalingMode(int mode);
private native final int native_getScalingMode();
private native final int native_setMeasurementMode(int mode);
private native final int native_getMeasurementMode();
private native final int native_getSamplingRate();
private native final int native_getWaveForm(byte[] waveform);
private native final int native_getFft(byte[] fft);
private native final int native_getPeakRms(MeasurementPeakRms measurement);
private native final int native_setPeriodicCapture(int rate, boolean waveForm, boolean fft);
//---------------------------------------------------------
// Java methods called from the native side
//--------------------
@SuppressWarnings("unused")
private static void postEventFromNative(Object effect_ref,
int what, int arg1, int arg2, Object obj) {
Visualizer visu = (Visualizer)((WeakReference)effect_ref).get();
if (visu == null) {
return;
}
if (visu.mNativeEventHandler != null) {
Message m = visu.mNativeEventHandler.obtainMessage(what, arg1, arg2, obj);
visu.mNativeEventHandler.sendMessage(m);
}
}
}
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