如何将散景/面板动画与 dash.js 之类的视频播放器同步？

问题描述

我正在使用散景和面板来创建动画图以及一些导航控件，例如滑块、播放/暂停、跳过 5 秒等。

同时，我希望与该动画同步显示视频片段。我开始使用 dash.js 并设法相应地准备视频并将其显示在独立页面中。 （耶！）

由于我对 javascript 了解不多，所以我想知道：是否有同步这两件事的解决方案？

（一个梦想场景：一个用于显示和控制来自 python 的 dash.js 视频播放器的面板小部件。嗯，可以希望，对吧？但我会接受任何提示、建议和想法。）

解决方法

回答我自己的问题，以防万一它可以为任何人节省一些试验和错误。

走进几个死胡同后，我编写了一个小型自定义散景小部件，可以满足我的需求。

代码如下：

from bokeh.core.properties import Bool,String,Float
from bokeh.models import Div

DASH_URL = <url to the dash.js lib>

JS_CODE = """
import * as p from "core/properties"
import {Div,DivView} from "models/widgets/div"

declare var dashjs: any

export type DashViewerData = {from: number,to: number}

export class DashViewerView extends DivView {
  model: DashViewer
  private video_el: HTMLElement
  private player: any  

  render(): void {
    super.render()
    this.video_el = document.createElement('video')
    this.video_el.id = this.model.video_element_id
    this.video_el.setAttribute('width',"1120px") 
    this.video_el.setAttribute('height',"630px")
    this.video_el.setAttribute('controls','')
    this.el.appendChild(this.video_el)
    this.el.appendChild(document.createTextNode(this.model.url))

    document.createElement('script')
    this.player = dashjs.MediaPlayer().create();
    this.player.initialize(this.video_el,this.model.url,this.model.is_playing);
  }

  play_listener(){
    if (this.model.is_playing){
      this.player.play()
    }
    else {
      this.player.pause()
    }
  }

  connect_signals(): void {
    this.connect(this.model.properties.is_playing.change,this.play_listener);
    this.connect(this.model.properties.time.change,()=>this.player.seek(this.model.time));
  }
}

export namespace DashViewer {
  export type Attrs = p.AttrsOf<Props>

  export type Props = Div.Props & {
    video_element_id: p.Property<string>
    url: p.Property<string>
    is_playing: p.Property<boolean>
    time: p.Property<number>
  }
}

export interface DashViewer extends DashViewer.Attrs {}

export class DashViewer extends Div {
  properties: DashViewer.Props
  __view_type__: DashViewerView

  constructor(attrs?: Partial<DashViewer.Attrs>) {
    super(attrs)
  }

  static init_DashViewer(): void {
    this.prototype.default_view = DashViewerView

    this.define<DashViewer.Props>({
      video_element_id: [p.String,'dashviewer_video'],url:              [p.String,''],is_playing:       [p.Boolean,false],time:             [p.Number,0.0]
    })
  }
}
"""


class DashViewer(Div):
    __implementation__ = JS_CODE
    __javascript__ = [DASH_URL]
    __css__ = []

    video_element_id = String(default='dash_player',help="id of the video element in the DOM")
    url = String(help="The URL from which to load the video. (This should point to an mpd file.)")
    is_playing = Bool(default=False)
    time = Float(default=0.0,help="Time in seconds. Change this to make the player jump to that time.")