AudioRenderer开发音频播放功能(ArkTS)(1)

};

let audioRendererInfo: audio.AudioRendererInfo = {
usage: audio.StreamUsage.STREAM_USAGE_VOICE_COMMUNICATION,
rendererFlags: 0
};

let audioRendererOptions: audio.AudioRendererOptions = {
streamInfo: audioStreamInfo,
rendererInfo: audioRendererInfo
};

audio.createAudioRenderer(audioRendererOptions, (err, data) => {
if (err) {
console.error(Invoke createAudioRenderer failed, code is ${err.code}, message is ${err.message});
return;
} else {
console.info(‘Invoke createAudioRenderer succeeded.’);
let audioRenderer = data;
}
});

2. 调用start()方法进入running状态，开始渲染音频。

import { BusinessError } from ‘@ohos.base’;

audioRenderer.start((err: BusinessError) => {
if (err) {
console.error(Renderer start failed, code is ${err.code}, message is ${err.message});
} else {
console.info(‘Renderer start success.’);
}
});

3. 指定待渲染文件地址，打开文件调用write()方法向缓冲区持续写入音频数据进行渲染播放。如果需要对音频数据进行处理以实现个性化的播放，在写入之前操作即可。

import fs from ‘@ohos.file.fs’;

let context = getContext(this);
async function read() {
const bufferSize: number = await audioRenderer.getBufferSize();
let path = context.filesDir;

const filePath = path + ‘/voice_call_data.wav’;
let file: fs.File = fs.openSync(filePath, fs.OpenMode.READ_ONLY);
let buf = new ArrayBuffer(bufferSize);
let readsize: number = await fs.read(file.fd, buf);
let writeSize: number = await audioRenderer.write(buf);
}

4. 调用stop()方法停止渲染。

import { BusinessError } from ‘@ohos.base’;

audioRenderer.stop((err: BusinessError) => {
if (err) {
console.error(Renderer stop failed, code is ${err.code}, message is ${err.message});
} else {
console.info(‘Renderer stopped.’);
}
});

5. 调用release()方法销毁实例，释放资源。

import { BusinessError } from ‘@ohos.base’;

audioRenderer.release((err: BusinessError) => {
if (err) {
console.error(Renderer release failed, code is ${err.code}, message is ${err.message});
} else {
console.info(‘Renderer released.’);
}
});

#### 完整示例


下面展示了使用AudioRenderer渲染音频文件的示例代码。

import audio from ‘@ohos.multimedia.audio’;
import fs from ‘@ohos.file.fs’;

const TAG = ‘AudioRendererDemo’;

let context = getContext(this);
let renderModel: audio.AudioRenderer | 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 audioRendererInfo: audio.AudioRendererInfo = {
usage: audio.StreamUsage.STREAM_USAGE_MUSIC, // 音频流使用类型
rendererFlags: 0 // 音频渲染器标志
}
let audioRendererOptions: audio.AudioRendererOptions = {
streamInfo: audioStreamInfo,
rendererInfo: audioRendererInfo
}

// 初始化，创建实例，设置监听事件
async function init() {
audio.createAudioRenderer(audioRendererOptions, (err, renderer) => { // 创建AudioRenderer实例
if (!err) {
console.info(${TAG}: creating AudioRenderer success);
renderModel = renderer;
if (renderModel !== undefined) {
(renderModel as audio.AudioRenderer).on(‘stateChange’, (state: audio.AudioState) => { // 设置监听事件，当转换到指定的状态时触发回调
if (state == 2) {
console.info(‘audio renderer state is: STATE_RUNNING’);
}
});
(renderModel as audio.AudioRenderer).on(‘markReach’, 1000, (position: number) => { // 订阅markReach事件，当渲染的帧数达到1000帧时触发回调
if (position == 1000) {
console.info(‘ON Triggered successfully’);
}
});
}
} else {
console.info(${TAG}: creating AudioRenderer failed, error: ${err.message});
}
});
}

// 开始一次音频渲染
async function start() {
if (renderModel !== undefined) {
let stateGroup = [audio.AudioState.STATE_PREPARED, audio.AudioState.STATE_PAUSED, audio.AudioState.STATE_STOPPED];
if (stateGroup.indexOf((renderModel as audio.AudioRenderer).state.valueOf()) === -1) { // 当且仅当状态为prepared、paused和stopped之一时才能启动渲染
console.error(TAG + ‘start failed’);
return;
}
await (renderModel as audio.AudioRenderer).start(); // 启动渲染

const bufferSize = await (renderModel as audio.AudioRenderer).getBufferSize();

let path = context.filesDir;
const filePath = path + '/test.wav'; // 使用沙箱路径获取文件，实际路径为/data/storage/el2/base/haps/entry/files/test.wav

let file = fs.openSync(filePath, fs.OpenMode.READ_ONLY);
let stat = await fs.stat(filePath);
let buf = new ArrayBuffer(bufferSize);
let len = stat.size % bufferSize === 0 ? Math.floor(stat.size / bufferSize) : Math.floor(stat.size / bufferSize + 1);
class Options {
  offset: number = 0;
  length: number = 0
}
for (let i = 0; i < len; i++) {
  let options: Options = {
    offset: i * bufferSize,
    length: bufferSize
  };
  let readsize = await fs.read(file.fd, buf, options);
  
  // buf是要写入缓冲区的音频数据，在调用AudioRenderer.write()方法前可以进行音频数据的预处理，实现个性化的音频播放功能，AudioRenderer会读出写入缓冲区的音频数据进行渲染
  
  let writeSize: number = await (renderModel as audio.AudioRenderer).write(buf);
    if ((renderModel as audio.AudioRenderer).state.valueOf() === audio.AudioState.STATE_RELEASED) { // 如果渲染器状态为released，关闭资源
    fs.close(file);
  }
  if ((renderModel as audio.AudioRenderer).state.valueOf() === audio.AudioState.STATE_RUNNING) {
    if (i === len - 1) { // 如果音频文件已经被读取完，停止渲染
      fs.close(file);
      await (renderModel as audio.AudioRenderer).stop();
    }
  }
}

}
}

// 暂停渲染
async function pause() {
if (renderModel !== undefined) {
// 只有渲染器状态为running的时候才能暂停
if ((renderModel as audio.AudioRenderer).state.valueOf() !== audio.AudioState.STATE_RUNNING) {
console.info(‘Renderer is not running’);
return;
}
await (renderModel as audio.AudioRenderer).pause(); // 暂停渲染
if ((renderModel as audio.AudioRenderer).state.valueOf() === audio.AudioState.STATE_PAUSED) {
console.info(‘Renderer is paused.’);
} else {
console.error(‘Pausing renderer failed.’);
}
}
}

// 停止渲染
async function stop() {
if (renderModel !== undefined) {
// 只有渲染器状态为running或paused的时候才可以停止
if ((renderModel as audio.AudioRenderer).state.valueOf() !== audio.AudioState.STATE_RUNNING && (renderModel as audio.AudioRenderer).state.valueOf() !== audio.AudioState.STATE_PAUSED) {
console.info(‘Renderer is not running or paused.’);
return;
}
await (renderModel as audio.AudioRenderer).stop(); // 停止渲染
if ((renderModel as audio.AudioRenderer).state.valueOf() === audio.AudioState.STATE_STOPPED) {
console.info(‘Renderer stopped.’);
} else {
console.error(‘Stopping renderer failed.’);
}
}
}

// 销毁实例，释放资源
async function release() {
if (renderModel !== undefined) {
// 渲染器状态不是released状态，才能release
if (renderModel.state.valueOf() === audio.AudioState.STATE_RELEASED) {
console.info(‘Renderer already released’);
return;
}
await renderModel.release(); // 释放资源
if (renderModel.state.valueOf() === audio.AudioState.STATE_RELEASED) {
console.info(‘Renderer released’);
} else {
console.error(‘Renderer release failed.’);
}
}
}

当同优先级或高优先级音频流要使用输出设备时，当前音频流会被中断，应用可以自行响应中断事件并做出处理。具体的音频并发处理方式可参考[多音频播放的并发策略](/openharmony/docs/blob/master/zh-cn/application-dev/media/audio-playback-concurrency.md)。


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