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      1 /*
      2  * Copyright (C) 2010 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.musicvis;
     18 
     19 import android.util.Log;
     20 import android.media.audiofx.Visualizer;
     21 
     22 import java.util.Arrays;
     23 
     24 public class AudioCapture {
     25 
     26     private byte [] mRawVizData;
     27     private int [] mFormattedVizData;
     28     private byte [] mRawNullData = new byte[0];
     29     private int [] mFormattedNullData = new int[0];
     30 
     31     private Visualizer mVisualizer;
     32     private int mType;
     33 
     34     private static long MAX_IDLE_TIME_MS = 3000;
     35     private long mLastValidCaptureTimeMs;
     36 
     37     public static final int TYPE_PCM = 0;
     38     public static final int TYPE_FFT = 1;
     39 
     40 
     41     public AudioCapture(int type, int size) {
     42         mType = type;
     43         int[] range = new int[2];
     44 
     45         range = Visualizer.getCaptureSizeRange();
     46 
     47         if (size < range[0]) {
     48             size = range[0];
     49         }
     50         if (size > range[1]) {
     51             size = range[1];
     52         }
     53 
     54         mRawVizData = new byte[size];
     55         mFormattedVizData = new int[size];
     56 
     57         mVisualizer = null;
     58         try {
     59             mVisualizer = new Visualizer(0);
     60             if (mVisualizer != null) {
     61                 if (mVisualizer.getEnabled()) {
     62                     mVisualizer.setEnabled(false);
     63                 }
     64                 mVisualizer.setCaptureSize(mRawVizData.length);
     65             }
     66         } catch (UnsupportedOperationException e) {
     67             Log.e("AudioCapture", "Visualizer cstor UnsupportedOperationException");
     68         } catch (IllegalStateException e) {
     69             Log.e("AudioCapture", "Visualizer cstor IllegalStateException");
     70         } catch (RuntimeException e) {
     71             Log.e("AudioCapture", "Visualizer cstor RuntimeException");
     72         }
     73     }
     74 
     75     public void start() {
     76         if (mVisualizer != null) {
     77             try {
     78                 if (!mVisualizer.getEnabled()) {
     79                     mVisualizer.setEnabled(true);
     80                     mLastValidCaptureTimeMs = System.currentTimeMillis();
     81                 }
     82             } catch (IllegalStateException e) {
     83                 Log.e("AudioCapture", "start() IllegalStateException");
     84             }
     85         }
     86     }
     87 
     88     public void stop() {
     89         if (mVisualizer != null) {
     90             try {
     91                 if (mVisualizer.getEnabled()) {
     92                     mVisualizer.setEnabled(false);
     93                 }
     94             } catch (IllegalStateException e) {
     95                 Log.e("AudioCapture", "stop() IllegalStateException");
     96             }
     97         }
     98     }
     99 
    100     public void release() {
    101         if (mVisualizer != null) {
    102             mVisualizer.release();
    103             mVisualizer = null;
    104         }
    105     }
    106 
    107     public byte[] getRawData() {
    108         if (captureData()) {
    109             return mRawVizData;
    110         } else {
    111             return mRawNullData;
    112         }
    113     }
    114 
    115     public int[] getFormattedData(int num, int den) {
    116         if (captureData()) {
    117             if (mType == TYPE_PCM) {
    118                 for (int i = 0; i < mFormattedVizData.length; i++) {
    119                     // convert from unsigned 8 bit to signed 16 bit
    120                     int tmp = ((int)mRawVizData[i] & 0xFF) - 128;
    121                     // apply scaling factor
    122                     mFormattedVizData[i] = (tmp * num) / den;
    123                 }
    124             } else {
    125                 for (int i = 0; i < mFormattedVizData.length; i++) {
    126                     // apply scaling factor
    127                     mFormattedVizData[i] = ((int)mRawVizData[i] * num) / den;
    128                 }
    129             }
    130             return mFormattedVizData;
    131         } else {
    132             return mFormattedNullData;
    133         }
    134     }
    135 
    136     private boolean captureData() {
    137         int status = Visualizer.ERROR;
    138         boolean result = true;
    139         try {
    140             if (mVisualizer != null) {
    141                 if (mType == TYPE_PCM) {
    142                     status = mVisualizer.getWaveForm(mRawVizData);
    143                 } else {
    144                     status = mVisualizer.getFft(mRawVizData);
    145                 }
    146             }
    147         } catch (IllegalStateException e) {
    148             Log.e("AudioCapture", "captureData() IllegalStateException: "+this);
    149         } finally {
    150             if (status != Visualizer.SUCCESS) {
    151                 Log.e("AudioCapture", "captureData() :  "+this+" error: "+ status);
    152                 result = false;
    153             } else {
    154                 // return idle state indication if silence lasts more than MAX_IDLE_TIME_MS
    155                 byte nullValue = 0;
    156                 int i;
    157                 if (mType == TYPE_PCM) {
    158                     nullValue = (byte)0x80;
    159                 }
    160                 for (i = 0; i < mRawVizData.length; i++) {
    161                     if (mRawVizData[i] != nullValue) break;
    162                 }
    163                 if (i == mRawVizData.length) {
    164                     if ((System.currentTimeMillis() - mLastValidCaptureTimeMs) >
    165                          MAX_IDLE_TIME_MS) {
    166                         result = false;
    167                     }
    168                 } else {
    169                     mLastValidCaptureTimeMs = System.currentTimeMillis();
    170                 }
    171             }
    172         }
    173         return result;
    174     }
    175 }
    176