HarmonyOS 鸿蒙Next中如何使用avplayer实现边播边缓存能力

可以通过设置avplayer的datasrc属性实现边播边缓存能力。

文档地址：https://developer.huawei.com/consumer/cn/doc/harmonyos-references/arkts-apis-media-avplayer

将缓存下来数据写入到本地临时文件中， 然后读取临时文件中的数据播放，即可实现边播边缓存的能力。

import media from ‘@ohos.multimedia.media’; import common from ‘@ohos.app.ability.common’; import { BusinessError } from ‘@ohos.base’; import rcp from ‘@hms.collaboration.rcp’; import fs from ‘@ohos.file.fs’; import connection from ‘@ohos.net.connection’; // const DOWNLOAD_URL = ‘https://sns-video-bd.xhscdn.com/stream/110/258/01e602cadc11542d010370038e7ae8b418_258.mp4’; // const DOWNLOAD_URL = ‘https://media.w3.org/2010/05/sintel/trailer.mp4’; const DOWNLOAD_URL = ‘https://ss0.bdstatic.com/-0U0bnSm1A5BphGlnYG/cae-legoup-video-target/93be3d88-9fc2-4fbd-bd14-833bca731ca7.mp4’; // const DOWNLOAD_URL = ‘https://vjs.zencdn.net/v/oceans.mp4’; const request = new rcp.Request(DOWNLOAD_URL); const session = rcp.createSession(); let context = getContext(this) as common.UIAbilityContext; let pathDir = context.filesDir; let path = pathDir + ‘/1234.mp4’; let bufferingStart = false; if (fs.accessSync(path)) { fs.unlinkSync(path); } const fd = fs.openSync(path, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE).fd; const readFd = fs.openSync(path, fs.OpenMode.READ_ONLY).fd; function GetDecodedBuffer(buffer: ArrayBuffer): ArrayBuffer { return buffer; } let g_from = 0; let g_to = 0; let recieve = 0; let last_recieve = 0; request.configuration = { tracing: { httpEventsHandler: { onDataReceive: (incomingData: ArrayBuffer) => { const writeLength = fs.writeSync(fd, GetDecodedBuffer(incomingData)); recieve+= writeLength; console.info('MineRcp recieve Length = ’ + writeLength.toString() + " , recieve = " + recieve); return incomingData.byteLength; } } } };

function download(length: number) { console.info('MineRcp download from = ’ + g_from + 'to = ’ + (g_from + length - 1)); request.transferRange = { from: g_from, to: g_from + length - 1, }; g_to = g_from + length - 1; g_from += length; session.fetch(request); } @Entry @Component struct AVPlayerDemo { xComponentController: XComponentController = new XComponentController(); surfaceID: string = ‘’; public xComponentContext: Record<string, () => void> = {} public player: media.AVPlayer | null = null; private fileSize: number = -1; private fd: number = 0; public isSeek: boolean = true; @State isBuffering: Visibility = Visibility.None; build() { Column() { Stack() { XComponent({ id: ‘AVPlayer’, type: XComponentType.SURFACE, controller: this.xComponentController }) .onLoad(() => { this.surfaceID = this.xComponentController.getXComponentSurfaceId() this.xComponentContext = this.xComponentController.getXComponentContext() as Record<string, () => void> }) Text(‘缓冲中。。。’) .visibility(this.isBuffering) .fontSize(20) .width(300) .textAlign(TextAlign.Center) .fontColor(Color.White) } Button(‘speed’) .onClick(() => { this.player?.setSpeed(media.PlaybackSpeed.SPEED_FORWARD_2_00_X); }) .margin({ right: 12 }) .margin({ top: 10 }) .width(150) Button(‘paused’) .onClick(() => { this.player?.pause(); }) .margin({ right: 12 }) .margin({ top: 20 }) .width(150) Button(‘seek’) .onClick(() => { this.player?.seek(9000, 0); }) .margin({ right: 12 }) .margin({ top: 20 }) .width(150) Button(‘player’) .onClick(() => { this.avPlayerDataSrcNOSeekDemo() }) .margin({ right: 12 }) .margin({ top: 20 }) .width(150) Button(‘reset’) .onClick(() => { this.player?.reset(); }) .margin({ right: 12 }) .margin({ top: 20 }) .width(150) } .margin({ top: 40 }) .height(400) } async avPlayerDataSrcNOSeekDemo() { download(1024 * 1024); // 获取播放文件的大小 const headResp = await session.head(DOWNLOAD_URL); this.fileSize = Number(headResp.headers[‘content-length’]); console.info('MineRcp fileSize = ’ + this.fileSize.toString()); // 创建avPlayer实例对象 this.player = await media.createAVPlayer(); // 创建状态机变化回调函数 this.setAVPlayerCallback(this.player);

// dataSrc播放模式的的播放源地址，当播放为Seek模式时fileSize为播放文件的具体大小，下面会对fileSize赋值
let src: media.AVDataSrcDescriptor = {
  fileSize: -1,
  callback: (buf: ArrayBuffer, length: number, pos?: number) => {
    let num = 0;
    if (buf == undefined || length == undefined) {
      return -1;
    }
    num = fs.readSync(readFd, buf);
    console.info('MineRcp cacheBuffer after checkBuffer Length = ' + num.toString() + ', pos: ' + pos + ', g_to: ' + g_to);
    if (num > 0) {
      if (pos != undefined && pos < g_to && g_to - pos < 100 * 1024) {
        console.info('MineRcp data not enough, download more');
        let downloadLength = 1024 * 1024;
        if (this.fileSize - g_from <= downloadLength) {
          downloadLength = this.fileSize - g_from;
        }
        download(downloadLength);
      }
      bufferingStart = false;
      return num;
    }
    if (num == 0) {
      console.info('MineRcp no data read, download more');
      if (!bufferingStart) {
        bufferingStart = true;
        let downloadLength = 1024 * 1024;
        if (this.fileSize - g_from <= downloadLength) {
          downloadLength = this.fileSize - g_from;
        }
        download(downloadLength);
      }
      return 0;
    }
    return -1;
  }
}
src.fileSize = this.fileSize;
this.isSeek = false; // 支持seek操作
this.player.dataSrc = src;

} // 注册avplayer回调函数 private setAVPlayerCallback(avPlayer: media.AVPlayer) { if (this.player === null) { return; } // // 响应API调用，监听seek()请求完成情况。 avPlayer.on(‘speedDone’, (number: Number) => this.speedDone(number)); avPlayer.on(‘seekDone’, (number: Number) => this.seekDone(number)); avPlayer.on(‘bufferingUpdate’, (infoType: media.BufferingInfoType, value: number) => { if (infoType == media.BufferingInfoType.BUFFERING_START) { this.isBuffering = Visibility.Visible; } if (infoType == media.BufferingInfoType.BUFFERING_END) { this.isBuffering = Visibility.None; } }); // 状态机变化回调函数 avPlayer.on(‘stateChange’, async (state: string, reason: media.StateChangeReason) => { switch (state) { case ‘idle’: // 成功调用reset接口后触发该状态机上报 console.info(‘AVPlayer state idle called.’); this.avPlayerDataSrcNOSeekDemo() //avPlayer.release(); // 调用release接口销毁实例对象 break; case ‘initialized’: // avplayer 设置播放源后触发该状态上报 console.info(‘AVPlayer state initialized called.’); avPlayer.surfaceId = this.surfaceID; // 设置显示画面，当播放的资源为纯音频时无需设置 console.info(‘prepare start.’); avPlayer.prepare(); console.info(‘prepare end.’); break; case ‘prepared’: // prepare调用成功后上报该状态机 console.info(‘AVPlayer state prepared called.’); avPlayer.play(); // 调用播放接口开始播放 break; case ‘playing’: // play成功调用后触发该状态机上报 console.info(‘AVPlayer state playing called.’); break; case ‘paused’: // pause成功调用后触发该状态机上报 console.info(‘AVPlayer state paused called.’); break; case ‘completed’: // 播放结束后触发该状态机上报 console.info(‘AVPlayer state completed called.’); avPlayer.stop(); //调用播放结束接口 break; case ‘stopped’: // stop接口成功调用后触发该状态机上报 console.info(‘AVPlayer state stopped called.’); avPlayer.release(); // 调用reset接口初始化avplayer状态 break; case ‘released’: console.info(‘AVPlayer state released called.’); fs.unlinkSync(path); session.cancel(request); break; default: console.info(‘AVPlayer state unknown called.’); break; } }) }

private speedDone(number: Number) { console.info(‘AVPlayer ## speedDone’); } // private seekDone(number: Number) { console.info(‘AVPlayer ## speedDone’); } }