1# 使用AudioCapturer开发音频录制功能 2 3AudioCapturer是音频采集器，用于录制PCM（Pulse Code Modulation）音频数据，适合有音频开发经验的开发者实现更灵活的录制功能。 4 5## 开发指导 6 7使用AudioCapturer录制音频涉及到AudioCapturer实例的创建、音频采集参数的配置、采集的开始与停止、资源的释放等。本开发指导将以一次录制音频数据的过程为例，向开发者讲解如何使用AudioCapturer进行音频录制，建议搭配[AudioCapturer的API说明](../../reference/apis-audio-kit/js-apis-audio.md#audiocapturer8)阅读。 8 9下图展示了AudioCapturer的状态变化，在创建实例后，调用对应的方法可以进入指定的状态实现对应的行为。需要注意的是在确定的状态执行不合适的方法可能导致AudioCapturer发生错误，建议开发者在调用状态转换的方法前进行状态检查，避免程序运行产生预期以外的结果。 10 11**图1** AudioCapturer状态变化示意图 12 13 14使用on('stateChange')方法可以监听AudioCapturer的状态变化，每个状态对应值与说明见[AudioState](../../reference/apis-audio-kit/js-apis-audio.md#audiostate8)。 15 16### 开发步骤及注意事项 17 181. 配置音频采集参数并创建AudioCapturer实例，音频采集参数的详细信息可以查看[AudioCapturerOptions](../../reference/apis-audio-kit/js-apis-audio.md#audiocaptureroptions8)。 19 20 ```ts 21 import audio from '@ohos.multimedia.audio'; 22 23 let audioStreamInfo: audio.AudioStreamInfo = { 24 samplingRate: audio.AudioSamplingRate.SAMPLE_RATE_44100, 25 channels: audio.AudioChannel.CHANNEL_2, 26 sampleFormat: audio.AudioSampleFormat.SAMPLE_FORMAT_S16LE, 27 encodingType: audio.AudioEncodingType.ENCODING_TYPE_RAW 28 }; 29 30 let audioCapturerInfo: audio.AudioCapturerInfo = { 31 source: audio.SourceType.SOURCE_TYPE_MIC, 32 capturerFlags: 0 33 }; 34 35 let audioCapturerOptions: audio.AudioCapturerOptions = { 36 streamInfo: audioStreamInfo, 37 capturerInfo: audioCapturerInfo 38 }; 39 40 audio.createAudioCapturer(audioCapturerOptions, (err, data) => { 41 if (err) { 42 console.error(`Invoke createAudioCapturer failed, code is ${err.code}, message is ${err.message}`); 43 } else { 44 console.info('Invoke createAudioCapturer succeeded.'); 45 let audioCapturer = data; 46 } 47 }); 48 ``` 49 502. 调用start()方法进入running状态，开始录制音频。 51 52 ```ts 53 import { BusinessError } from '@ohos.base'; 54 55 audioCapturer.start((err: BusinessError) => { 56 if (err) { 57 console.error(`Capturer start failed, code is ${err.code}, message is ${err.message}`); 58 } else { 59 console.info('Capturer start success.'); 60 } 61 }); 62 ``` 63 643. 指定录制文件地址，调用read()方法读取缓冲区的数据。 65 66 ```ts 67 import fs from '@ohos.file.fs'; 68 69 let context = getContext(this); 70 async function read() { 71 let path = context.filesDir; 72 const filePath = path + '/voice_call_data.wav'; 73 let file: fs.File = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE); 74 let bufferSize: number = await audioCapturer.getBufferSize(); 75 let buffer: ArrayBuffer = await audioCapturer.read(bufferSize, true); 76 fs.writeSync(file.fd, buffer); 77 } 78 ``` 79 804. 调用stop()方法停止录制。 81 82 ```ts 83 import { BusinessError } from '@ohos.base'; 84 85 audioCapturer.stop((err: BusinessError) => { 86 if (err) { 87 console.error(`Capturer stop failed, code is ${err.code}, message is ${err.message}`); 88 } else { 89 console.info('Capturer stopped.'); 90 } 91 }); 92 ``` 93 945. 调用release()方法销毁实例，释放资源。 95 96 ```ts 97 import { BusinessError } from '@ohos.base'; 98 99 audioCapturer.release((err: BusinessError) => { 100 if (err) { 101 console.error(`capturer release failed, code is ${err.code}, message is ${err.message}`); 102 } else { 103 console.info('capturer released.'); 104 } 105 }); 106 ``` 107 108 109### 完整示例 110 111下面展示了使用AudioCapturer录制音频的完整示例代码。 112 113```ts 114import audio from '@ohos.multimedia.audio'; 115import fs from '@ohos.file.fs'; 116 117const TAG = 'AudioCapturerDemo'; 118let context = getContext(this); 119 120let audioCapturer: audio.AudioCapturer | undefined = undefined; 121let audioStreamInfo: audio.AudioStreamInfo = { 122 samplingRate: audio.AudioSamplingRate.SAMPLE_RATE_44100, 123 channels: audio.AudioChannel.CHANNEL_1, 124 sampleFormat: audio.AudioSampleFormat.SAMPLE_FORMAT_S16LE, 125 encodingType: audio.AudioEncodingType.ENCODING_TYPE_RAW 126} 127let audioCapturerInfo: audio.AudioCapturerInfo = { 128 source: audio.SourceType.SOURCE_TYPE_MIC, // 音源类型 129 capturerFlags: 0 // 音频采集器标志 130} 131let audioCapturerOptions: audio.AudioCapturerOptions = { 132 streamInfo: audioStreamInfo, 133 capturerInfo: audioCapturerInfo 134} 135 136// 初始化，创建实例，设置监听事件 137async function init() { 138 audio.createAudioCapturer(audioCapturerOptions, (err, capturer) => { // 创建AudioCapturer实例 139 if (err) { 140 console.error(`Invoke createAudioCapturer failed, code is ${err.code}, message is ${err.message}`); 141 return; 142 } 143 console.info(`${TAG}: create AudioCapturer success`); 144 audioCapturer = capturer; 145 if (audioCapturer !== undefined) { 146 (audioCapturer as audio.AudioCapturer).on('markReach', 1000, (position: number) => { // 订阅markReach事件，当采集的帧数达到1000时触发回调 147 if (position === 1000) { 148 console.info('ON Triggered successfully'); 149 } 150 }); 151 (audioCapturer as audio.AudioCapturer).on('periodReach', 2000, (position: number) => { // 订阅periodReach事件，当采集的帧数达到2000时触发回调 152 if (position === 2000) { 153 console.info('ON Triggered successfully'); 154 } 155 }); 156 } 157 }); 158} 159 160// 开始一次音频采集 161async function start() { 162 if (audioCapturer !== undefined) { 163 let stateGroup = [audio.AudioState.STATE_PREPARED, audio.AudioState.STATE_PAUSED, audio.AudioState.STATE_STOPPED]; 164 if (stateGroup.indexOf((audioCapturer as audio.AudioCapturer).state.valueOf()) === -1) { // 当且仅当状态为STATE_PREPARED、STATE_PAUSED和STATE_STOPPED之一时才能启动采集 165 console.error(`${TAG}: start failed`); 166 return; 167 } 168 await (audioCapturer as audio.AudioCapturer).start(); // 启动采集 169 const filePath = context.filesDir + '/test.wav'; // 采集到的音频文件存储路径 170 let file: fs.File = fs.openSync(filePath, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE); // 如果文件不存在则创建文件 171 let fd = file.fd; 172 let numBuffersToCapture = 150; // 循环写入150次 173 let count = 0; 174 class Options { 175 offset: number = 0; 176 length: number = 0 177 } 178 while (numBuffersToCapture) { 179 let bufferSize = await (audioCapturer as audio.AudioCapturer).getBufferSize(); 180 let buffer = await (audioCapturer as audio.AudioCapturer).read(bufferSize, true); 181 let options: Options = { 182 offset: count * bufferSize, 183 length: bufferSize 184 }; 185 if (buffer === undefined) { 186 console.error(`${TAG}: read buffer failed`); 187 } else { 188 let number = fs.writeSync(fd, buffer, options); 189 console.info(`${TAG}: write date: ${number}`); 190 } 191 numBuffersToCapture--; 192 count++; 193 } 194 } 195} 196 197// 停止采集 198async function stop() { 199 if (audioCapturer !== undefined) { 200 // 只有采集器状态为STATE_RUNNING或STATE_PAUSED的时候才可以停止 201 if ((audioCapturer as audio.AudioCapturer).state.valueOf() !== audio.AudioState.STATE_RUNNING && (audioCapturer as audio.AudioCapturer).state.valueOf() !== audio.AudioState.STATE_PAUSED) { 202 console.info('Capturer is not running or paused'); 203 return; 204 } 205 await (audioCapturer as audio.AudioCapturer).stop(); // 停止采集 206 if ((audioCapturer as audio.AudioCapturer).state.valueOf() === audio.AudioState.STATE_STOPPED) { 207 console.info('Capturer stopped'); 208 } else { 209 console.error('Capturer stop failed'); 210 } 211 } 212} 213 214// 销毁实例，释放资源 215async function release() { 216 if (audioCapturer !== undefined) { 217 // 采集器状态不是STATE_RELEASED或STATE_NEW状态，才能release 218 if ((audioCapturer as audio.AudioCapturer).state.valueOf() === audio.AudioState.STATE_RELEASED || (audioCapturer as audio.AudioCapturer).state.valueOf() === audio.AudioState.STATE_NEW) { 219 console.info('Capturer already released'); 220 return; 221 } 222 await (audioCapturer as audio.AudioCapturer).release(); // 释放资源 223 if ((audioCapturer as audio.AudioCapturer).state.valueOf() === audio.AudioState.STATE_RELEASED) { 224 console.info('Capturer released'); 225 } else { 226 console.error('Capturer release failed'); 227 } 228 } 229} 230``` 231
