| /* |
| * 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 com.android.mediaframeworktest.functional; |
| |
| import android.media.audiofx.Visualizer; |
| import android.util.Log; |
| |
| /** |
| * The EnergyProbe class provides audio signal energy measurements based on the FFT returned |
| * by the Visualizer class. The measure is qualitative and not quantitative in that the returned |
| * value has no unit and is just proportional to the amount of energy present around the |
| * specified frequency. |
| */ |
| |
| public class EnergyProbe { |
| private String TAG = "EnergyProbe"; |
| |
| private static int CAPTURE_SIZE = 1024; |
| private static int MEASURE_COUNT = 5; |
| private static int AVERAGE_COUNT = 3; |
| |
| private Visualizer mVisualizer = null; |
| private int mMaxFrequency = 0; |
| private int mCapturePeriodMs; |
| private byte[] mFft = new byte[CAPTURE_SIZE]; |
| |
| public EnergyProbe(int session) { |
| try { |
| mVisualizer = new Visualizer(session); |
| if (mVisualizer != null) { |
| mVisualizer.setCaptureSize(CAPTURE_SIZE); |
| mMaxFrequency = mVisualizer.getSamplingRate() / 2000; |
| mCapturePeriodMs = 1000000 / mVisualizer.getMaxCaptureRate(); |
| } |
| } catch (UnsupportedOperationException e) { |
| Log.e(TAG, "Error creating visualizer"); |
| } catch (IllegalStateException e) { |
| Log.e(TAG, "Error configuring visualizer"); |
| } |
| } |
| |
| public int capture(int freq) throws InterruptedException { |
| int energy = 0; |
| int count = 0; |
| |
| if (freq > mMaxFrequency) { |
| return 0; |
| } |
| |
| if (mVisualizer != null) { |
| try { |
| mVisualizer.setEnabled(true); |
| for (int i = 0; i < MEASURE_COUNT; i++) { |
| if (mVisualizer.getFft(mFft) == Visualizer.SUCCESS) { |
| if (freq == mMaxFrequency) { |
| energy += (int)mFft[0] * (int)mFft[0]; |
| } else { |
| int bin = 2 * (freq * CAPTURE_SIZE / mMaxFrequency / 2); |
| if (bin < 2) bin = 2; |
| int tmp = 0; |
| int j; |
| for (j = 0; |
| (j < AVERAGE_COUNT) && ((bin + 2 * j) < CAPTURE_SIZE); |
| j++) { |
| tmp += (int)mFft[bin + 2 * j] * (int)mFft[bin + 2 * j] + |
| (int)mFft[bin + 2 * j + 1] * (int)mFft[bin + 2 * j + 1]; |
| } |
| // j is always != 0 |
| energy += tmp/j; |
| } |
| count++; |
| } |
| Thread.sleep(mCapturePeriodMs); |
| } |
| mVisualizer.setEnabled(false); |
| } catch (IllegalStateException e) { |
| Log.e(TAG, "Error capturing audio"); |
| } |
| } |
| if (count == 0) { |
| return 0; |
| } |
| return energy/count; |
| } |
| |
| public void release() { |
| if (mVisualizer != null) { |
| mVisualizer.release(); |
| mVisualizer = null; |
| } |
| } |
| } |