1 /* 2 * Copyright (c) 2013 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 // The functions in this file are called from native code. They can still be 12 // accessed even though they are declared private. 13 14 package org.webrtc.voiceengine; 15 16 import android.content.Context; 17 import android.content.pm.PackageManager; 18 import android.media.AudioManager; 19 20 class AudioManagerAndroid { 21 // Most of Google lead devices use 44.1K as the default sampling rate, 44.1K 22 // is also widely used on other android devices. 23 private static final int DEFAULT_SAMPLING_RATE = 44100; 24 // Randomly picked up frame size which is close to return value on N4. 25 // Return this default value when 26 // getProperty(PROPERTY_OUTPUT_FRAMES_PER_BUFFER) fails. 27 private static final int DEFAULT_FRAMES_PER_BUFFER = 256; 28 29 private int mNativeOutputSampleRate; 30 private boolean mAudioLowLatencySupported; 31 private int mAudioLowLatencyOutputFrameSize; 32 33 34 @SuppressWarnings("unused") AudioManagerAndroid(Context context)35 private AudioManagerAndroid(Context context) { 36 AudioManager audioManager = (AudioManager) 37 context.getSystemService(Context.AUDIO_SERVICE); 38 39 mNativeOutputSampleRate = DEFAULT_SAMPLING_RATE; 40 mAudioLowLatencyOutputFrameSize = DEFAULT_FRAMES_PER_BUFFER; 41 if (android.os.Build.VERSION.SDK_INT >= 42 android.os.Build.VERSION_CODES.JELLY_BEAN_MR1) { 43 String sampleRateString = audioManager.getProperty( 44 AudioManager.PROPERTY_OUTPUT_SAMPLE_RATE); 45 if (sampleRateString != null) { 46 mNativeOutputSampleRate = Integer.parseInt(sampleRateString); 47 } 48 String framesPerBuffer = audioManager.getProperty( 49 AudioManager.PROPERTY_OUTPUT_FRAMES_PER_BUFFER); 50 if (framesPerBuffer != null) { 51 mAudioLowLatencyOutputFrameSize = Integer.parseInt(framesPerBuffer); 52 } 53 } 54 mAudioLowLatencySupported = context.getPackageManager().hasSystemFeature( 55 PackageManager.FEATURE_AUDIO_LOW_LATENCY); 56 } 57 58 @SuppressWarnings("unused") getNativeOutputSampleRate()59 private int getNativeOutputSampleRate() { 60 return mNativeOutputSampleRate; 61 } 62 63 @SuppressWarnings("unused") isAudioLowLatencySupported()64 private boolean isAudioLowLatencySupported() { 65 return mAudioLowLatencySupported; 66 } 67 68 @SuppressWarnings("unused") getAudioLowLatencyOutputFrameSize()69 private int getAudioLowLatencyOutputFrameSize() { 70 return mAudioLowLatencyOutputFrameSize; 71 } 72 }