1 /* 2 * Copyright (C) 2015 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 #pragma once 18 19 #include <system/audio.h> 20 #include <utils/Log.h> 21 #include <math.h> 22 23 // Absolute min volume in dB (can be represented in single precision normal float value) 24 #define VOLUME_MIN_DB (-758) 25 26 class VolumeCurvePoint 27 { 28 public: 29 int mIndex; 30 float mDBAttenuation; 31 }; 32 33 /** 34 * device categories used for volume curve management. 35 */ 36 enum device_category { 37 DEVICE_CATEGORY_HEADSET, 38 DEVICE_CATEGORY_SPEAKER, 39 DEVICE_CATEGORY_EARPIECE, 40 DEVICE_CATEGORY_EXT_MEDIA, 41 DEVICE_CATEGORY_CNT 42 }; 43 44 class Volume 45 { 46 public: 47 /** 48 * 4 points to define the volume attenuation curve, each characterized by the volume 49 * index (from 0 to 100) at which they apply, and the attenuation in dB at that index. 50 * we use 100 steps to avoid rounding errors when computing the volume in volIndexToDb() 51 * 52 * @todo shall become configurable 53 */ 54 enum { 55 VOLMIN = 0, 56 VOLKNEE1 = 1, 57 VOLKNEE2 = 2, 58 VOLMAX = 3, 59 60 VOLCNT = 4 61 }; 62 63 /** 64 * extract one device relevant for volume control from multiple device selection 65 * 66 * @param[in] device for which the volume category is associated 67 * 68 * @return subset of device required to limit the number of volume category per device 69 */ getDeviceForVolume(audio_devices_t device)70 static audio_devices_t getDeviceForVolume(audio_devices_t device) 71 { 72 if (device == AUDIO_DEVICE_NONE) { 73 // this happens when forcing a route update and no track is active on an output. 74 // In this case the returned category is not important. 75 device = AUDIO_DEVICE_OUT_SPEAKER; 76 } else if (popcount(device) > 1) { 77 // Multiple device selection is either: 78 // - speaker + one other device: give priority to speaker in this case. 79 // - one A2DP device + another device: happens with duplicated output. In this case 80 // retain the device on the A2DP output as the other must not correspond to an active 81 // selection if not the speaker. 82 // - HDMI-CEC system audio mode only output: give priority to available item in order. 83 if (device & AUDIO_DEVICE_OUT_SPEAKER) { 84 device = AUDIO_DEVICE_OUT_SPEAKER; 85 } else if (device & AUDIO_DEVICE_OUT_SPEAKER_SAFE) { 86 device = AUDIO_DEVICE_OUT_SPEAKER_SAFE; 87 } else if (device & AUDIO_DEVICE_OUT_HDMI_ARC) { 88 device = AUDIO_DEVICE_OUT_HDMI_ARC; 89 } else if (device & AUDIO_DEVICE_OUT_AUX_LINE) { 90 device = AUDIO_DEVICE_OUT_AUX_LINE; 91 } else if (device & AUDIO_DEVICE_OUT_SPDIF) { 92 device = AUDIO_DEVICE_OUT_SPDIF; 93 } else { 94 device = (audio_devices_t)(device & AUDIO_DEVICE_OUT_ALL_A2DP); 95 } 96 } 97 98 /*SPEAKER_SAFE is an alias of SPEAKER for purposes of volume control*/ 99 if (device == AUDIO_DEVICE_OUT_SPEAKER_SAFE) 100 device = AUDIO_DEVICE_OUT_SPEAKER; 101 102 ALOGW_IF(popcount(device) != 1, 103 "getDeviceForVolume() invalid device combination: %08x", 104 device); 105 106 return device; 107 } 108 109 /** 110 * returns the category the device belongs to with regard to volume curve management 111 * 112 * @param[in] device to check upon the category to whom it belongs to. 113 * 114 * @return device category. 115 */ getDeviceCategory(audio_devices_t device)116 static device_category getDeviceCategory(audio_devices_t device) 117 { 118 switch(getDeviceForVolume(device)) { 119 case AUDIO_DEVICE_OUT_EARPIECE: 120 return DEVICE_CATEGORY_EARPIECE; 121 case AUDIO_DEVICE_OUT_WIRED_HEADSET: 122 case AUDIO_DEVICE_OUT_WIRED_HEADPHONE: 123 case AUDIO_DEVICE_OUT_BLUETOOTH_SCO: 124 case AUDIO_DEVICE_OUT_BLUETOOTH_SCO_HEADSET: 125 case AUDIO_DEVICE_OUT_BLUETOOTH_A2DP: 126 case AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_HEADPHONES: 127 return DEVICE_CATEGORY_HEADSET; 128 case AUDIO_DEVICE_OUT_LINE: 129 case AUDIO_DEVICE_OUT_AUX_DIGITAL: 130 /*USB? Remote submix?*/ 131 return DEVICE_CATEGORY_EXT_MEDIA; 132 case AUDIO_DEVICE_OUT_SPEAKER: 133 case AUDIO_DEVICE_OUT_BLUETOOTH_SCO_CARKIT: 134 case AUDIO_DEVICE_OUT_BLUETOOTH_A2DP_SPEAKER: 135 case AUDIO_DEVICE_OUT_USB_ACCESSORY: 136 case AUDIO_DEVICE_OUT_USB_DEVICE: 137 case AUDIO_DEVICE_OUT_REMOTE_SUBMIX: 138 default: 139 return DEVICE_CATEGORY_SPEAKER; 140 } 141 } 142 DbToAmpl(float decibels)143 static inline float DbToAmpl(float decibels) 144 { 145 if (decibels <= VOLUME_MIN_DB) { 146 return 0.0f; 147 } 148 return exp( decibels * 0.115129f); // exp( dB * ln(10) / 20 ) 149 } 150 AmplToDb(float amplification)151 static inline float AmplToDb(float amplification) 152 { 153 if (amplification == 0) { 154 return VOLUME_MIN_DB; 155 } 156 return 20 * log10(amplification); 157 } 158 159 }; 160