harmony 鸿蒙使用AudioCapturer开发音频录制功能
使用AudioCapturer开发音频录制功能
AudioCapturer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。
开发指导
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说明阅读。
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。
图1 AudioCapturer状态变化示意图
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。
开发步骤及注意事项
- 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。
说明: 当设置Mic音频源(即SourceType为SOURCE_TYPE_MIC、SOURCE_TYPE_VOICE_RECOGNITION、SOURCE_TYPE_VOICE_COMMUNICATION、SOURCE_TYPE_VOICE_MESSAGE)时,需要申请麦克风权限ohos.permission.MICROPHONE,申请方式参考:向用户申请授权。
import { audio } from '@kit.AudioKit';
let audioStreamInfo: audio.AudioStreamInfo = {
samplingRate: audio.AudioSamplingRate.SAMPLE_RATE_48000, // 采样率。
channels: audio.AudioChannel.CHANNEL_2, // 通道。
sampleFormat: audio.AudioSampleFormat.SAMPLE_FORMAT_S16LE, // 采样格式。
encodingType: audio.AudioEncodingType.ENCODING_TYPE_RAW // 编码格式。
};
let audioCapturerInfo: audio.AudioCapturerInfo = {
source: audio.SourceType.SOURCE_TYPE_MIC, // 音源类型:Mic音频源。根据业务场景配置,参考SourceType。
capturerFlags: 0 // 音频采集器标志。
};
let audioCapturerOptions: audio.AudioCapturerOptions = {
streamInfo: audioStreamInfo,
capturerInfo: audioCapturerInfo
};
audio.createAudioCapturer(audioCapturerOptions, (err, data) => {
if (err) {
console.error(`Invoke createAudioCapturer failed, code is ${err.code}, message is ${err.message}`);
} else {
console.info('Invoke createAudioCapturer succeeded.');
let audioCapturer = data;
}
});
- 调用on(‘readData’)方法,订阅监听音频数据读入回调。
> 注意:
> - 线程管理:不建议使用多线程来处理数据读取。若需使用多线程读取数据,需要做好线程管理。
> - 线程耗时:
readData
方法所在的线程中,不建议执行耗时任务。否则可能会导致数据处理线程响应回调延迟,进而引发录音数据缺失、卡顿、杂音等音频效果问题。
import { BusinessError } from '@kit.BasicServicesKit';
import { fileIo as fs } from '@kit.CoreFileKit';
import { common } from '@kit.AbilityKit';
class Options {
offset?: number;
length?: number;
}
let bufferSize: number = 0;
// 请在组件内获取context,确保this.getUIContext().getHostContext()返回结果为UIAbilityContext。
let context = this.getUIContext().getHostContext() as common.UIAbilityContext;
let path = context.cacheDir;
let filePath = path + '/StarWars10s-2C-48000-4SW.pcm';
let file: fs.File = fs.openSync(filePath, fs.OpenMode.READ_WRITE|fs.OpenMode.CREATE);
let readDataCallback = (buffer: ArrayBuffer) => {
let options: Options = {
offset: bufferSize,
length: buffer.byteLength
}
fs.writeSync(file.fd, buffer, options);
bufferSize += buffer.byteLength;
};
audioCapturer.on('readData', readDataCallback);
- 调用start()方法进入running状态,开始录制音频。
import { BusinessError } from '@kit.BasicServicesKit';
audioCapturer.start((err: BusinessError) => {
if (err) {
console.error(`Capturer start failed, code is ${err.code}, message is ${err.message}`);
} else {
console.info('Capturer start success.');
}
});
- 调用stop()方法停止录制。
import { BusinessError } from '@kit.BasicServicesKit';
audioCapturer.stop((err: BusinessError) => {
if (err) {
console.error(`Capturer stop failed, code is ${err.code}, message is ${err.message}`);
} else {
console.info('Capturer stopped.');
}
});
- 调用release()方法销毁实例,释放资源。
import { BusinessError } from '@kit.BasicServicesKit';
audioCapturer.release((err: BusinessError) => {
if (err) {
console.error(`capturer release failed, code is ${err.code}, message is ${err.message}`);
} else {
console.info('capturer released.');
}
});
完整示例
下面展示了使用AudioCapturer录制音频的完整示例代码。
import { audio } from '@kit.AudioKit';
import { BusinessError } from '@kit.BasicServicesKit';
import { fileIo as fs } from '@kit.CoreFileKit';
import { common } from '@kit.AbilityKit';
const TAG = 'AudioCapturerDemo';
class Options {
offset?: number;
length?: number;
}
let bufferSize: number = 0;
let audioCapturer: audio.AudioCapturer|undefined = undefined;
let audioStreamInfo: audio.AudioStreamInfo = {
samplingRate: audio.AudioSamplingRate.SAMPLE_RATE_48000, // 采样率。
channels: audio.AudioChannel.CHANNEL_2, // 通道。
sampleFormat: audio.AudioSampleFormat.SAMPLE_FORMAT_S16LE, // 采样格式。
encodingType: audio.AudioEncodingType.ENCODING_TYPE_RAW // 编码格式。
};
let audioCapturerInfo: audio.AudioCapturerInfo = {
source: audio.SourceType.SOURCE_TYPE_MIC, // 音源类型:Mic音频源。根据业务场景配置,参考SourceType。
capturerFlags: 0 // 音频采集器标志。
};
let audioCapturerOptions: audio.AudioCapturerOptions = {
streamInfo: audioStreamInfo,
capturerInfo: audioCapturerInfo
};
// 请在组件内获取context,确保this.getUIContext().getHostContext()返回结果为UIAbilityContext。
let context = this.getUIContext().getHostContext() as common.UIAbilityContext;
let path = context.cacheDir;
let filePath = path + '/StarWars10s-2C-48000-4SW.pcm';
let file: fs.File = fs.openSync(filePath, fs.OpenMode.READ_WRITE|fs.OpenMode.CREATE);
let readDataCallback = (buffer: ArrayBuffer) => {
let options: Options = {
offset: bufferSize,
length: buffer.byteLength
}
fs.writeSync(file.fd, buffer, options);
bufferSize += buffer.byteLength;
};
// 初始化,创建实例,设置监听事件。
function init() {
audio.createAudioCapturer(audioCapturerOptions, (err, capturer) => { // 创建AudioCapturer实例。
if (err) {
console.error(`Invoke createAudioCapturer failed, code is ${err.code}, message is ${err.message}`);
return;
}
console.info(`${TAG}: create AudioCapturer success`);
audioCapturer = capturer;
if (audioCapturer !== undefined) {
(audioCapturer as audio.AudioCapturer).on('readData', readDataCallback);
}
});
}
// 开始一次音频采集。
function start() {
if (audioCapturer !== undefined) {
let stateGroup = [audio.AudioState.STATE_PREPARED, audio.AudioState.STATE_PAUSED, audio.AudioState.STATE_STOPPED];
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。
console.error(`${TAG}: start failed`);
return;
}
// 启动采集。
(audioCapturer as audio.AudioCapturer).start((err: BusinessError) => {
if (err) {
console.error('Capturer start failed.');
} else {
console.info('Capturer start success.');
}
});
}
}
// 停止采集。
function stop() {
if (audioCapturer !== undefined) {
// 只有采集器状态为STATE_RUNNING或STATE_PAUSED的时候才可以停止。
if ((audioCapturer as audio.AudioCapturer).state.valueOf() !== audio.AudioState.STATE_RUNNING && (audioCapturer as audio.AudioCapturer).state.valueOf() !== audio.AudioState.STATE_PAUSED) {
console.info('Capturer is not running or paused');
return;
}
//停止采集。
(audioCapturer as audio.AudioCapturer).stop((err: BusinessError) => {
if (err) {
console.error('Capturer stop failed.');
} else {
fs.close(file);
console.info('Capturer stop success.');
}
});
}
}
// 销毁实例,释放资源。
function release() {
if (audioCapturer !== undefined) {
// 采集器状态不是STATE_RELEASED或STATE_NEW状态,才能release。
if ((audioCapturer as audio.AudioCapturer).state.valueOf() === audio.AudioState.STATE_RELEASED||(audioCapturer as audio.AudioCapturer).state.valueOf() === audio.AudioState.STATE_NEW) {
console.info('Capturer already released');
return;
}
//释放资源。
(audioCapturer as audio.AudioCapturer).release((err: BusinessError) => {
if (err) {
console.error('Capturer release failed.');
} else {
console.info('Capturer release success.');
}
});
}
}
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