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 * Starts hotword recognition. 41 * <p> 42 * On calling this, the system streams audio from the device microphone to this application's 43 * {@link HotwordDetectionService}. Audio is streamed until {@link #stopRecognition()} is 44 * called. 45 * <p> 46 * On detection of a hotword, 47 * {@link AlwaysOnHotwordDetector.Callback#onDetected(AlwaysOnHotwordDetector.EventPayload)} 48 * is called on the callback provided when creating this {@link HotwordDetector}. 49 * <p> 50 * There is a noticeable impact on battery while recognition is active, so make sure to call 51 * {@link #stopRecognition()} when detection isn't needed. 52 * <p> 53 * Calling this again while recognition is active does nothing. 54 * 55 * @return true if the request to start recognition succeeded 56 */ 57 @RequiresPermission(allOf = {RECORD_AUDIO, CAPTURE_AUDIO_HOTWORD}) startRecognition()58 boolean startRecognition(); 59 60 /** 61 * Stops hotword recognition. 62 * 63 * @return true if the request to stop recognition succeeded 64 */ stopRecognition()65 boolean stopRecognition(); 66 67 /** 68 * Starts hotword recognition on audio coming from an external connected microphone. 69 * <p> 70 * {@link #stopRecognition()} must be called before {@code audioStream} is closed. 71 * 72 * @param audioStream stream containing the audio bytes to run detection on 73 * @param audioFormat format of the encoded audio 74 * @param options options supporting detection, such as configuration specific to the 75 * source of the audio. This will be provided to the {@link HotwordDetectionService}. 76 * PersistableBundle does not allow any remotable objects or other contents that can be 77 * used to communicate with other processes. 78 * @return true if the request to start recognition succeeded 79 */ startRecognition( @onNull ParcelFileDescriptor audioStream, @NonNull AudioFormat audioFormat, @Nullable PersistableBundle options)80 boolean startRecognition( 81 @NonNull ParcelFileDescriptor audioStream, 82 @NonNull AudioFormat audioFormat, 83 @Nullable PersistableBundle options); 84 85 /** 86 * Set configuration and pass read-only data to hotword detection service. 87 * 88 * @param options Application configuration data to provide to the 89 * {@link HotwordDetectionService}. PersistableBundle does not allow any remotable objects or 90 * other contents that can be used to communicate with other processes. 91 * @param sharedMemory The unrestricted data blob to provide to the 92 * {@link HotwordDetectionService}. Use this to provide the hotword models data or other 93 * such data to the trusted process. 94 * 95 * @throws IllegalStateException if this HotwordDetector wasn't specified to use a 96 * {@link HotwordDetectionService} when it was created. 97 */ updateState(@ullable PersistableBundle options, @Nullable SharedMemory sharedMemory)98 void updateState(@Nullable PersistableBundle options, @Nullable SharedMemory sharedMemory); 99 100 /** 101 * The callback to notify of detection events. 102 */ 103 interface Callback { 104 105 /** 106 * Called when the keyphrase is spoken. 107 * 108 * @param eventPayload Payload data for the detection event. 109 */ 110 // TODO: Consider creating a new EventPayload that the AOHD one subclasses. onDetected(@onNull AlwaysOnHotwordDetector.EventPayload eventPayload)111 void onDetected(@NonNull AlwaysOnHotwordDetector.EventPayload eventPayload); 112 113 /** 114 * Called when the detection fails due to an error. 115 */ onError()116 void onError(); 117 118 /** 119 * Called when the recognition is paused temporarily for some reason. 120 * This is an informational callback, and the clients shouldn't be doing anything here 121 * except showing an indication on their UI if they have to. 122 */ onRecognitionPaused()123 void onRecognitionPaused(); 124 125 /** 126 * Called when the recognition is resumed after it was temporarily paused. 127 * This is an informational callback, and the clients shouldn't be doing anything here 128 * except showing an indication on their UI if they have to. 129 */ onRecognitionResumed()130 void onRecognitionResumed(); 131 132 /** 133 * Called when the {@link HotwordDetectionService second stage detection} did not detect the 134 * keyphrase. 135 * 136 * @param result Info about the second stage detection result, provided by the 137 * {@link HotwordDetectionService}. 138 */ onRejected(@onNull HotwordRejectedResult result)139 void onRejected(@NonNull HotwordRejectedResult result); 140 141 /** 142 * Called when the {@link HotwordDetectionService} is created by the system and given a 143 * short amount of time to report it's initialization state. 144 * 145 * @param status Info about initialization state of {@link HotwordDetectionService}; the 146 * allowed values are {@link HotwordDetectionService#INITIALIZATION_STATUS_SUCCESS}, 147 * 1<->{@link HotwordDetectionService#getMaxCustomInitializationStatus()}, 148 * {@link HotwordDetectionService#INITIALIZATION_STATUS_UNKNOWN}. 149 */ onHotwordDetectionServiceInitialized(int status)150 void onHotwordDetectionServiceInitialized(int status); 151 152 /** 153 * Called with the {@link HotwordDetectionService} is restarted. 154 * 155 * Clients are expected to call {@link HotwordDetector#updateState} to share the state with 156 * the newly created service. 157 */ onHotwordDetectionServiceRestarted()158 void onHotwordDetectionServiceRestarted(); 159 } 160 } 161