媒体子系统是 OpenHarmony 中重要的子系统，可以提供音视频播放能力。媒体子系统为开发者提供一套简单且易于理解的接口，使得开发者能够方便接入系统并使用系统的媒体资源。媒体子系统提供以下常用功能：
从 3.2 开始 OpenHarmony 推出了 AVPlayer 和 AVRecorder 接口，之前的 VideoPlayer、AudioPlayer 这些接口会停止维护，所以我们今天学习下怎么使用 AVPlayer 接口
import media from '@ohos.multimedia.media';`
this.avPlayer = await media.createAVPlayer()`
如上，我们使用的是 promise 接口，对应的接口定义为：
/**
* Creates an AVPlayer instance.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param callback Callback used to return AVPlayer instance if the operation is successful; returns null otherwise.
* @throws { BusinessError } 5400101 - No memory. Return by callback.
*/
function createAVPlayer(callback: AsyncCallback<AVPlayer>): void;
/**
* Creates an AVPlayer instance.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @returns A Promise instance used to return AVPlayer instance if the operation is successful; returns null otherwise.
* @throws { BusinessError } 5400101 - No memory. Return by promise.
*/
function createAVPlayer() : Promise<AVPlayer>;`
* 注册 avplayer 回调
`//注册状态变化回调，不同状态时做不同动作
avPlayer.on('stateChange', async (state, reason) => {
……
}）
//注册时间变化回调，方便更新进度条时间
avPlayer.on('timeUpdate', (time:number) => {
……
})
//视频播放伪代码
async avPlayerDemo() {
this.avPlayer.on('stateChange', async (state, reason) => {
switch (state) {
case 'idle': // 成功调用reset接口后触发该状态机上报
console.info(TAG + 'state idle called')
this.avPlayer.release() // 释放avplayer对象
break;
case 'initialized': // avplayer 设置播放源后触发该状态上报
console.info(TAG + 'state initialized called ')
this.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
this.avPlayer.prepare().then(() => {
console.info(TAG+ 'prepare success');
}, (err) => {
console.error(TAG + 'prepare filed,error message is :' + err.message)
})
break;
case 'prepared': // prepare调用成功后上报该状态机
console.info(TAG + 'state prepared called')
this.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(TAG + 'state playing called')
if (this.count == 0) {
this.avPlayer.pause() // 调用暂停播放接口
} else {
this.avPlayer.seek(10000, media.SeekMode.SEEK_PREV_SYNC) // 前向seek置10秒处,触发seekDone回调函数
}
break;
case 'paused': // pause成功调用后触发该状态机上报
console.info(TAG + 'state paused called')
if (this.count == 0) {
this.count++
this.avPlayer.play() // 继续调用播放接口开始播放
}
break;
case 'completed': // 播放结束后触发该状态机上报
console.info(TAG + 'state completed called')
this.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(TAG + 'state stopped called')
this.avPlayer.reset() // 调用reset接口初始化avplayer状态
break;
case 'released':
console.info(TAG + 'state released called')
break;
case 'error':
console.info(TAG + 'state error called')
break;
default:
console.info(TAG + 'unkown state :' + state)
break;
}
})
// 创建avPlayer实例对象
this.avPlayer = await media.createAVPlayer()
let fdPath = 'fd://'
let pathDir = "/data/storage/el2/base/haps/entry/files" // pathDir在FA模型和Stage模型的获取方式不同，请参考开发步骤首行的说明，根据实际情况自行获取。
// path路径的码流可通过"hdc file send D:\xxx\H264_AAC.mp4 /data/app/el2/100/base/ohos.acts.multimedia.media.avplayer/haps/entry/files" 命令，将其推送到设备上
let path = pathDir + '/H264_AAC.mp4'
let file = await fs.open(path)
fdPath = fdPath + '' + file.fd
//赋值url后就会进入stateChange callback
this.avPlayer.url = fdPath
}
/**
* Prepare audio/video playback, it will request resource for playing.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param callback A callback instance used to return when prepare completed.
* @throws { BusinessError } 5400102 - Operation not allowed. Return by callback.
* @throws { BusinessError } 5400106 - Unsupport format. Return by callback.
*/
prepare(callback: AsyncCallback<void>): void;
/**
* Prepare audio/video playback, it will request resource for playing.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @returns A Promise instance used to return when prepare completed.
* @throws { BusinessError } 5400102 - Operation not allowed. Return by promise.
* @throws { BusinessError } 5400106 - Unsupport format. Return by promise.
*/
prepare(): Promise<void>;
/**
* Play audio/video playback.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param callback A callback instance used to return when play completed.
* @throws { BusinessError } 5400102 - Operation not allowed. Return by callback.
*/
play(callback: AsyncCallback<void>): void;
/**
* Play audio/video playback.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @returns A Promise instance used to return when play completed.
* @throws { BusinessError } 5400102 - Operation not allowed. Return by promise.
*/
play(): Promise<void>;
/**
* Pause audio/video playback.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param callback A callback instance used to return when pause completed.
* @throws { BusinessError } 5400102 - Operation not allowed. Return by callback.
*/
pause(callback: AsyncCallback<void>): void;
/**
* Pause audio/video playback.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @returns A Promise instance used to return when pause completed.
* @throws { BusinessError } 5400102 - Operation not allowed. Return by promise.
*/
pause(): Promise<void>;
/**
* Stop audio/video playback.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param callback A callback instance used to return when stop completed.
* @throws { BusinessError } 5400102 - Operation not allowed. Return by callback.
*/
stop(callback: AsyncCallback<void>): void;
/**
* Stop audio/video playback.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @returns A Promise instance used to return when stop completed.
* @throws { BusinessError } 5400102 - Operation not allowed. Return by promise.
*/
stop(): Promise<void>;
/**
* Reset AVPlayer, it will to idle state and can set src again.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param callback A callback instance used to return when reset completed.
* @throws { BusinessError } 5400102 - Operation not allowed. Return by callback.
*/
reset(callback: AsyncCallback<void>): void;
/**
* Reset AVPlayer, it will to idle state and can set src again.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @returns A Promise instance used to return when reset completed.
* @throws { BusinessError } 5400102 - Operation not allowed. Return by promise.
*/
reset(): Promise<void>;
/**
* Releases resources used for AVPlayer.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param callback A callback instance used to return when release completed.
* @throws { BusinessError } 5400102 - Operation not allowed. Return by callback.
*/
release(callback: AsyncCallback<void>): void;
/**
* Releases resources used for AVPlayer.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @returns A Promise instance used to return when release completed.
* @throws { BusinessError } 5400102 - Operation not allowed. Return by promise.
*/
release(): Promise<void>;
/**
* Jumps to the specified playback position.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param timeMs Playback position to jump, should be in [0, duration].
* @param mode See @SeekMode .
*/
seek(timeMs: number, mode?:SeekMode): void;`
/**
* Register or unregister listens for media playback events.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param type Type of the playback event to listen for.
* @param callback Callback used to listen for the playback stateChange event.
*/
on(type: 'stateChange', callback: (state: AVPlayerState, reason: StateChangeReason) => void): void;
off(type: 'stateChange'): void;
/**
* Register or unregister listens for media playback events.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param type Type of the playback event to listen for.
* @param callback Callback used to listen for the playback volume event.
*/
on(type: 'volumeChange', callback: Callback<number>): void;
off(type: 'volumeChange'): void;
/**
* Register or unregister listens for media playback events.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param type Type of the playback event to listen for.
* @param callback Callback used to listen for the playback end of stream
*/
on(type: 'endOfStream', callback: Callback<void>): void;
off(type: 'endOfStream'): void;
/**
* Register or unregister listens for media playback events.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param type Type of the playback event to listen for.
* @param callback Callback used to listen for the playback seekDone event.
*/
on(type: 'seekDone', callback: Callback<number>): void;
off(type: 'seekDone'): void;
/**
* Register or unregister listens for media playback events.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param type Type of the playback event to listen for.
* @param callback Callback used to listen for the playback speedDone event.
*/
on(type: 'speedDone', callback: Callback<number>): void;
off(type: 'speedDone'): void;
/**
* Register or unregister listens for media playback events.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param type Type of the playback event to listen for.
* @param callback Callback used to listen for the playback setBitrateDone event.
*/
on(type: 'bitrateDone', callback: Callback<number>): void;
off(type: 'bitrateDone'): void;
/**
* LRegister or unregister listens for media playback events.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param type Type of the playback event to listen for.
* @param callback Callback used to listen for the playback timeUpdate event.
*/
on(type: 'timeUpdate', callback: Callback<number>): void;
off(type: 'timeUpdate'): void;
/**
* Register or unregister listens for media playback events.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param type Type of the playback event to listen for.
* @param callback Callback used to listen for the playback durationUpdate event.
*/
on(type: 'durationUpdate', callback: Callback<number>): void;
off(type: 'durationUpdate'): void;
/**
* Register or unregister listens for video playback buffering events.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param type Type of the playback buffering update event to listen for.
* @param callback Callback used to listen for the buffering update event, return BufferingInfoType and the value.
*/
on(type: 'bufferingUpdate', callback: (infoType: BufferingInfoType, value: number) => void): void;
off(type: 'bufferingUpdate'): void;
/**
* Register or unregister listens for start render video frame events.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param type Type of the playback event to listen for.
* @param callback Callback used to listen for the playback event return .
*/
on(type: 'startRenderFrame', callback: Callback<void>): void;
off(type: 'startRenderFrame'): void;
/**
* Register or unregister listens for video size change event.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param type Type of the playback event to listen for.
* @param callback Callback used to listen for the playback event return video size.
*/
on(type: 'videoSizeChange', callback: (width: number, height: number) => void): void;
off(type: 'videoSizeChange'): void;
/**
* Register or unregister listens for audio interrupt event, refer to {@link #audio.InterruptEvent}
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param type Type of the playback event to listen for.
* @param callback Callback used to listen for the playback event return audio interrupt info.
*/
on(type: 'audioInterrupt', callback: (info: audio.InterruptEvent) => void): void;
off(type: 'audioInterrupt'): void;
/**
* Register or unregister listens for available bitrate list collect completed events for HLS protocol stream playback.
* This event will be reported after the {@link #prepare} called.
* @since 9
* @syscap SystemCapability.Multimedia.Media.AVPlayer
* @param type Type of the playback event to listen for.
* @param callback Callback used to listen for the playback event return available bitrate list.
*/
on(type: 'availableBitrates', callback: (bitrates: Array<number>) => void): void;
off(type: 'availableBitrates'): void;
build() {
Stack({ alignContent: Alignment.Center }) {
if (this.isShowMenu) {
Column() {
//视频名称
PlayTitle({ title: this.displayName, handleBack: this.handleBack })
Row() {
//播放控件
PreVideo({ handleClick: this.handlePrevClick })
PlayButton({ isPlaying: $isPlaying })
NextVideo({ handleClick: this.handleNextClick })
}
.margin({ top: '40%' })
Blank()
//时间刻度
Row() {
Text(getTimeString(this.currentTime))
.fontSize(25)
.fontColor(Color.White)
Blank()
Text(this.fileAsset ? getTimeString(this.fileAsset.duration) : '00:00')
.fontSize(25)
.fontColor(Color.White)
}
.width('95%')
//进度条
Slider({ value: this.fileAsset ? this.currentTime / this.fileAsset.duration * 100 : 0 })
.width('92%')
.selectedColor(Color.White)
.onChange((value: number) => {
Logger.info(TAG, 'seek time change')
this.currentTime = this.fileAsset.duration * value / 100
this.videoPlayer.seek(this.currentTime)
})
}
.height('100%')
.zIndex(2)
}
Row() {
XComponent({
id: 'componentId',
type: 'surface',
controller: this.mxcomponentController
})
.onLoad(() => {
Logger.info(TAG, 'onLoad is called')
this.playVideo()
})
.width('100%')
.aspectRatio(this.ratio)
}
.height('100%')
.width('100%')
.justifyContent(FlexAlign.Center)
}
.width('100%')
.height('100%')
.backgroundColor(Color.Black)
.onClick(() => {
this.isShowMenu = !this.isShowMenu
})
}
//根据视频文件获取视频源尺寸并生成surface
//视频文件的路径在/storage/media/100/local/files/Videos
async prepareVideo() {
this.ratio = this.fileAsset.width / this.fileAsset.height
this.mxcomponentController.setXComponentsurfaceSize({
surfaceWidth: this.fileAsset.width,
surfaceHeight: this.fileAsset.height
})
this.surfaceId = this.mxcomponentController.getXComponentsurfaceId()
this.fd = await this.fileAsset.open('Rw')
Logger.info(TAG, `fd://' ${this.fd} `)
return 'fd://' + this.fd
}
//初始化视频文件并初始化avplayer
async playVideo() {
Logger.info(TAG, 'playVideo')
try{
await this.getMediaList()
let fdPath = await this.prepareVideo()
this.videoPlayer.on('timeUpdate', (time:number) => {
console.info('timeUpdate success,and new time is :' + time)
this.currentTime = time;
})
await this.videoPlayer.initVideoPlayer(fdPath, this.surfaceId)
this.isPlaying = true
}catch(error) {
Logger.info(TAG, `playVideo error ${JSON.stringify(error)}`)
}
}
为了能让大家更好的学习鸿蒙（HarmonyOS NEXT）开发技术，这边特意整理了《鸿蒙开发学习手册》（共计890页），希望对大家有所帮助：
1.项目开发必备面试题
2.性能优化方向
3.架构方向
4.鸿蒙开发系统底层方向
5.鸿蒙音视频开发方向
6.鸿蒙车载开发方向
7.鸿蒙南向开发方向