1 /* 2 * Copyright (C) 2021 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 android.service.voice; 18 19 import static android.Manifest.permission.CAPTURE_AUDIO_HOTWORD; 20 import static android.Manifest.permission.RECORD_AUDIO; 21 22 import android.annotation.NonNull; 23 import android.annotation.Nullable; 24 import android.annotation.RequiresPermission; 25 import android.annotation.SystemApi; 26 import android.media.AudioFormat; 27 import android.os.ParcelFileDescriptor; 28 import android.os.PersistableBundle; 29 import android.os.SharedMemory; 30 31 /** 32 * Basic functionality for hotword detectors. 33 * 34 * @hide 35 */ 36 @SystemApi 37 public interface HotwordDetector { 38 39 /** 40 * Indicates that it is a non-trusted hotword detector. 41 * 42 * @hide 43 */ 44 int DETECTOR_TYPE_NORMAL = 0; 45 46 /** 47 * Indicates that it is a DSP trusted hotword detector. 48 * 49 * @hide 50 */ 51 int DETECTOR_TYPE_TRUSTED_HOTWORD_DSP = 1; 52 53 /** 54 * Indicates that it is a software trusted hotword detector. 55 * 56 * @hide 57 */ 58 int DETECTOR_TYPE_TRUSTED_HOTWORD_SOFTWARE = 2; 59 60 /** 61 * Starts hotword recognition. 62 * <p> 63 * On calling this, the system streams audio from the device microphone to this application's 64 * {@link HotwordDetectionService}. Audio is streamed until {@link #stopRecognition()} is 65 * called. 66 * <p> 67 * On detection of a hotword, 68 * {@link AlwaysOnHotwordDetector.Callback#onDetected(AlwaysOnHotwordDetector.EventPayload)} 69 * is called on the callback provided when creating this {@link HotwordDetector}. 70 * <p> 71 * There is a noticeable impact on battery while recognition is active, so make sure to call 72 * {@link #stopRecognition()} when detection isn't needed. 73 * <p> 74 * Calling this again while recognition is active does nothing. 75 * 76 * @return true if the request to start recognition succeeded 77 */ 78 @RequiresPermission(allOf = {RECORD_AUDIO, CAPTURE_AUDIO_HOTWORD}) startRecognition()79 boolean startRecognition(); 80 81 /** 82 * Stops hotword recognition. 83 * 84 * @return true if the request to stop recognition succeeded 85 */ stopRecognition()86 boolean stopRecognition(); 87 88 /** 89 * Starts hotword recognition on audio coming from an external connected microphone. 90 * <p> 91 * {@link #stopRecognition()} must be called before {@code audioStream} is closed. 92 * 93 * @param audioStream stream containing the audio bytes to run detection on 94 * @param audioFormat format of the encoded audio 95 * @param options options supporting detection, such as configuration specific to the 96 * source of the audio. This will be provided to the {@link HotwordDetectionService}. 97 * PersistableBundle does not allow any remotable objects or other contents that can be 98 * used to communicate with other processes. 99 * @return true if the request to start recognition succeeded 100 */ startRecognition( @onNull ParcelFileDescriptor audioStream, @NonNull AudioFormat audioFormat, @Nullable PersistableBundle options)101 boolean startRecognition( 102 @NonNull ParcelFileDescriptor audioStream, 103 @NonNull AudioFormat audioFormat, 104 @Nullable PersistableBundle options); 105 106 /** 107 * Set configuration and pass read-only data to hotword detection service. 108 * 109 * @param options Application configuration data to provide to the 110 * {@link HotwordDetectionService}. PersistableBundle does not allow any remotable objects or 111 * other contents that can be used to communicate with other processes. 112 * @param sharedMemory The unrestricted data blob to provide to the 113 * {@link HotwordDetectionService}. Use this to provide the hotword models data or other 114 * such data to the trusted process. 115 * 116 * @throws IllegalStateException if this HotwordDetector wasn't specified to use a 117 * {@link HotwordDetectionService} when it was created. 118 */ updateState(@ullable PersistableBundle options, @Nullable SharedMemory sharedMemory)119 void updateState(@Nullable PersistableBundle options, @Nullable SharedMemory sharedMemory); 120 121 /** 122 * Invalidates this hotword detector so that any future calls to this result 123 * in an {@link IllegalStateException}. 124 * 125 * <p>If there are no other {@link HotwordDetector} instances linked to the 126 * {@link HotwordDetectionService}, the service will be shutdown. 127 */ destroy()128 default void destroy() { 129 throw new UnsupportedOperationException("Not implemented. Must override in a subclass."); 130 } 131 132 /** 133 * @hide 134 */ detectorTypeToString(int detectorType)135 static String detectorTypeToString(int detectorType) { 136 switch (detectorType) { 137 case DETECTOR_TYPE_NORMAL: 138 return "normal"; 139 case DETECTOR_TYPE_TRUSTED_HOTWORD_DSP: 140 return "trusted_hotword_dsp"; 141 case DETECTOR_TYPE_TRUSTED_HOTWORD_SOFTWARE: 142 return "trusted_hotword_software"; 143 default: 144 return Integer.toString(detectorType); 145 } 146 } 147 148 /** 149 * The callback to notify of detection events. 150 */ 151 interface Callback { 152 153 /** 154 * Called when the keyphrase is spoken. 155 * 156 * @param eventPayload Payload data for the detection event. 157 */ 158 // TODO: Consider creating a new EventPayload that the AOHD one subclasses. onDetected(@onNull AlwaysOnHotwordDetector.EventPayload eventPayload)159 void onDetected(@NonNull AlwaysOnHotwordDetector.EventPayload eventPayload); 160 161 /** 162 * Called when the detection fails due to an error. 163 */ onError()164 void onError(); 165 166 /** 167 * Called when the recognition is paused temporarily for some reason. 168 * This is an informational callback, and the clients shouldn't be doing anything here 169 * except showing an indication on their UI if they have to. 170 */ onRecognitionPaused()171 void onRecognitionPaused(); 172 173 /** 174 * Called when the recognition is resumed after it was temporarily paused. 175 * This is an informational callback, and the clients shouldn't be doing anything here 176 * except showing an indication on their UI if they have to. 177 */ onRecognitionResumed()178 void onRecognitionResumed(); 179 180 /** 181 * Called when the {@link HotwordDetectionService second stage detection} did not detect the 182 * keyphrase. 183 * 184 * @param result Info about the second stage detection result, provided by the 185 * {@link HotwordDetectionService}. 186 */ onRejected(@onNull HotwordRejectedResult result)187 void onRejected(@NonNull HotwordRejectedResult result); 188 189 /** 190 * Called when the {@link HotwordDetectionService} is created by the system and given a 191 * short amount of time to report it's initialization state. 192 * 193 * @param status Info about initialization state of {@link HotwordDetectionService}; the 194 * allowed values are {@link HotwordDetectionService#INITIALIZATION_STATUS_SUCCESS}, 195 * 1<->{@link HotwordDetectionService#getMaxCustomInitializationStatus()}, 196 * {@link HotwordDetectionService#INITIALIZATION_STATUS_UNKNOWN}. 197 */ onHotwordDetectionServiceInitialized(int status)198 void onHotwordDetectionServiceInitialized(int status); 199 200 /** 201 * Called with the {@link HotwordDetectionService} is restarted. 202 * 203 * Clients are expected to call {@link HotwordDetector#updateState} to share the state with 204 * the newly created service. 205 */ onHotwordDetectionServiceRestarted()206 void onHotwordDetectionServiceRestarted(); 207 } 208 } 209