Live Share 媒体功能 - Teams

项目
11/16/2023

视频和音频是现代世界和工作场所的重要部分。我们收到了广泛的反馈，即我们可以做更多工作来提高在会议中一起观看视频的质量、可访问性和许可证保护。

Live Share SDK 只需几行代码即可实现任何 HTML <video> 和<audio>元素的可靠媒体同步。通过在播放器状态和传输控件层同步媒体，可以单独赋予视图和许可证，同时提供通过应用可获得的最高质量。

安装

Live Share 媒体是在 npm 上发布的 JavaScript 包，可以通过 npm 或 yarn 下载。还必须安装其对等依赖项，其中包括 @microsoft/live-share、 fluid-framework 和 @fluidframework/azure-client。如果在选项卡应用程序中使用 Live Share，则还必须安装 @microsoft/teams-js 版本 2.11.0 或更高版本。

npm install @microsoft/live-share @microsoft/live-share-media fluid-framework @fluidframework/azure-client --save
npm install @microsoft/teams-js --save

若要使用 Yarn 将最新版本的 SDK 添加到应用程序，请执行以下操作：

yarn add @microsoft/live-share @microsoft/live-share-media fluid-framework @fluidframework/azure-client
yarn add @microsoft/teams-js

媒体同步概述

Live Share SDK 有两个与媒体同步相关的主类：

课程	说明
`LiveMediaSession`	自定义实时对象，旨在协调独立媒体流中的媒体传输控件和播放状态。
MediaPlayerSynchronizer	使用 `LiveMediaSession`同步实现`IMediaPlayer`接口的任何对象（包括 HTML5 `<video>` 和 `<audio>` ）。

示例：

<body>
  <video id="player">
    <source src="YOUR_VIDEO_SRC" type="video/mp4" />
  </video>
</body>

import {
  LiveShareClient,
  UserMeetingRole,
  MediaPlayerSynchronizerEvents,
} from "@microsoft/live-share";
import { LiveMediaSession } from "@microsoft/live-share-media";
import { LiveShareHost } from "@microsoft/teams-js";

// Setup the Fluid container
const host = LiveShareHost.create();
const liveShare = new LiveShareClient(host);
const schema = {
  initialObjects: { mediaSession: LiveMediaSession },
};
const { container } = await liveShare.joinContainer(schema);
const { mediaSession } = container.initialObjects;

// Get the player from your document and create synchronizer
const player = document.getElementById("player");
const synchronizer = mediaSession.synchronize(player);

// Listen for groupaction events (optional)
synchronizer.addEventListener(MediaPlayerSynchronizerEvents.groupaction, async (evt) => {
  // See which user made the change (e.g., to display a notification)
  const clientInfo = await synchronizer.mediaSession.getClientInfo(evt.details.clientId);
});

// Define roles you want to allow playback control and start sync
const allowedRoles = [UserMeetingRole.organizer, UserMeetingRole.presenter];
await mediaSession.initialize(allowedRoles);

import {
  LiveShareClient,
  UserMeetingRole,
  MediaPlayerSynchronizerEvents,
} from "@microsoft/live-share";
import { LiveMediaSession, IMediaPlayer, MediaPlayerSynchronizer } from "@microsoft/live-share-media";
import { LiveShareHost } from "@microsoft/teams-js";
import { ContainerSchema } from "fluid-framework";

// Join the Fluid container
const host = LiveShareHost.create();
const liveShare = new LiveShareClient(host);
const schema: ContainerSchema = {
  initialObjects: { mediaSession: LiveMediaSession },
};
const { container } = await liveShare.joinContainer(schema);
// Force casting is necessary because Fluid does not maintain type recognition for `container.initialObjects`.
// Casting here is always safe, as the `initialObjects` is constructed based on the schema you provide to `.joinContainer`.
const mediaSession = container.initialObjects.mediaSession as unknown as LiveMediaSession;

// Get the player from your document and create synchronizer
const player: IMediaPlayer = document.getElementById("player") as HTMLVideoElement;
const synchronizer: MediaPlayerSynchronizer = mediaSession.synchronize(player);

// Listen for groupaction events (optional)
synchronizer.addEventListener(MediaPlayerSynchronizerEvents.groupaction, async (evt) => {
  // See which user made the change (e.g., to display a notification)
  const clientInfo = await synchronizer.mediaSession.getClientInfo(evt.details.clientId);
});

// Define roles you want to allow playback control and start sync
const allowedRoles: UserMeetingRole[] = [UserMeetingRole.organizer, UserMeetingRole.presenter];
await mediaSession.initialize(allowedRoles);

import { useMediaSynchronizer } from "@microsoft/live-share-react";
import { UserMeetingRole } from "@microsoft/live-share";
import { MediaPlayerSynchronizerEvents } from "@microsoft/live-share-media";
import { useRef, useEffect } from "react";

const ALLOWED_ROLES = [UserMeetingRole.organizer, UserMeetingRole.presenter];

const INITIAL_TRACK = "<YOUR_VIDEO_URL>";

// Define a unique key that distinguishes this `useMediaSynchronizer` from others in your app
const UNIQUE_KEY = "MEDIA-SESSION-ID";

export function VideoPlayer() {
  const videoRef = useRef(null);
  const { play, pause, seekTo, mediaSynchronizer } = useMediaSynchronizer(
    UNIQUE_KEY,
    videoRef,
    INITIAL_TRACK,
    ALLOWED_ROLES
  );

  // Listen for groupaction events (optional)
  useEffect(() => {
    // Listen for player group actions for errors (e.g., play error)
    const onGroupAction = (evt: IMediaPlayerSynchronizerEvent) => {
      // See which user made the change (e.g., to display a notification)
      const clientInfo = await synchronizer.mediaSession.getClientInfo(evt.details.clientId);
    };
    mediaSynchronizer?.addEventListener(
      MediaPlayerSynchronizerEvents.groupaction,
      onGroupAction
    );
    return () => {
      mediaSynchronizer?.removeEventListener(
        MediaPlayerSynchronizerEvents.groupaction,
        onGroupAction
      );
    };
  }, [mediaSynchronizer]);

  return (
    <div>
      <video ref={videoRef} />
      <button onClick={play}>
        Play
      </button>
      <button onClick={pause}>
        Pause
      </button>
      <button onClick={() => {
        seekTo(0);
      }}>
        Start over
      </button>
    </div>
  );
}

自动 LiveMediaSession 侦听组播放状态的更改。 MediaPlayerSynchronizer 侦听由 LiveMediaSession 发出的状态更改，并将其应用于提供 IMediaPlayer 的对象，例如 HTML5 <video> 或 <audio> 元素。为了避免播放用户未有意启动的状态更改（如缓冲区事件），我们必须通过同步器调用传输控件，而不是直接通过播放器调用传输控件。

示例：

<body>
  <video id="player">
    <source src="YOUR_VIDEO_SRC" type="video/mp4" />
  </video>
  <div class="player-controls">
    <button id="play-button">Play</button>
    <button id="pause-button">Pause</button>
    <button id="restart-button">Restart</button>
    <button id="change-track-button">Change track</button>
  </div>
</body>

// ...

document.getElementById("play-button").onclick = async () => {
  // Will play for all users in the session.
  // If using role verification, this will throw an error if the user doesn't have the required role.
  await synchronizer.play();
};

document.getElementById("pause-button").onclick = async () => {
  // Will pause for all users in the session.
  // If using role verification, this will throw an error if the user doesn't have the required role.
  await synchronizer.pause();
};

document.getElementById("restart-button").onclick = async () => {
  // Will seek for all users in the session.
  // If using role verification, this will throw an error if the user doesn't have the required role.
  await synchronizer.seekTo(0);
};

document.getElementById("change-track-button").onclick = () => {
  // Will change the track for all users in the session.
  // If using role verification, this will throw an error if the user doesn't have the required role.
  synchronizer.setTrack({
    trackIdentifier: "SOME_OTHER_VIDEO_SRC",
  });
};

注意

虽然可以使用 LiveMediaSession 对象手动同步媒体，但通常建议使用 MediaPlayerSynchronizer。根据你在应用中使用的播放器，你可能需要创建一个委托填充码，以使 Web 播放器的界面与 IMediaPlayer 界面匹配。

挂起和等待点

如果要暂时挂起 LiveMediaSession 对象的同步，可以使用挂起功能。 MediaSessionCoordinatorSuspension默认情况下，对象是本地对象，这在用户可能想要赶上错过的内容、休息一下等情况时非常有用。如果用户结束挂起，同步将自动恢复。

// Suspend the media session coordinator
const suspension = mediaSession.coordinator.beginSuspension();

// End the suspension when ready
suspension.end();

import { MediaSessionCoordinatorSuspension } from "@microsoft/live-share-media";

// Suspend the media session coordinator
const suspension: MediaSessionCoordinatorSuspension = mediaSession.coordinator.beginSuspension();

// End the suspension when ready
suspension.end();

import { useMediaSynchronizer } from "@microsoft/live-share-react";
import { useRef } from "react";

// Define a unique key that distinguishes this `useMediaSynchronizer` from others in your app
const UNIQUE_KEY = "MEDIA-SESSION-ID";

// Example component
export function VideoPlayer() {
  const videoRef = useRef(null);
  const { suspended, beginSuspension, endSuspension } = useMediaSynchronizer(
    UNIQUE_KEY,
    videoRef,
    "<YOUR_INITIAL_VIDEO_URL>",
  );

  return (
    <div>
      <video ref={videoRef} />
      {!suspended && (
        <button onClick={() => {
          beginSuspension();
        }}>
          Stop following
        </button>
      )}
      {suspended && (
        <button onClick={() => {
          endSuspension();
        }}>
          Sync to presenter
        </button>
      )}
    </div>
  );
}

开始挂起时，还可以包含可选的 CoordinationWaitPoint 参数，该参数允许用户定义所有用户应在其中发生挂起的时间戳。在所有用户结束该等待点的挂起之前，同步不会恢复。

下面是一些等待点特别有用的方案：

在视频中的某些点添加测验或调查。
等待每个人在视频开始前或缓冲时适当加载视频。
允许演示者选择视频中的点进行群组讨论。

// Suspend the media session coordinator
const waitPoint = {
  position: 0,
  reason: "ReadyUp", // Optional.
};
const suspension = mediaSession.coordinator.beginSuspension(waitPoint);
// End the suspension when the user readies up
document.getElementById("ready-up-button").onclick = () => {
  // Sync will resume when everyone has ended suspension
  suspension.end();
};

import { MediaSessionCoordinatorSuspension, CoordinationWaitPoint } from "@microsoft/live-share-media";

// Suspend the media session coordinator
const waitPoint: CoordinationWaitPoint = {
  position: 0,
  reason: "ReadyUp", // Optional.
};
const suspension = mediaSession.coordinator.beginSuspension(waitPoint);

// End the suspension when the user readies up
document.getElementById("ready-up-button")!.onclick = () => {
  // Sync will resume when everyone has ended suspension
  suspension.end();
};

import { useMediaSynchronizer } from "@microsoft/live-share-react";
import { useRef } from "react";

// Define a unique key that distinguishes this `useMediaSynchronizer` from others in your app
const UNIQUE_KEY = "MEDIA-SESSION-ID";

// Example component
export function VideoPlayer() {
    const videoRef = useRef(null);
    const { suspended, beginSuspension, endSuspension } = useMediaSynchronizer(
        UNIQUE_KEY,
        videoRef,
        "<YOUR_INITIAL_VIDEO_URL>",
    );
    
    return (
      <div>
          <video ref={videoRef} />
          {!suspended && (
            <button onClick={() => {
                const waitPoint = {
                  position: 0,
                  reason: "ReadyUp", // Optional.
                };
                beginSuspension(waitPoint);
            }}>
                Wait until ready
            </button>
          )}
          {suspended && (
            <button onClick={() => {
              endSuspension();
            }}>
                Ready up
            </button>
          )}
      </div>
    );
}

音频闪避

Live Share SDK 支持智能音频闪避。通过在代码中添加以下内容，可以在应用程序中使用此功能：

import { meeting } from "@microsoft/teams-js";

// ... set up MediaPlayerSynchronizer

// Register speaking state change handler through Microsoft Teams JavaScript client library (TeamsJS)
let volumeTimer;
meeting.registerSpeakingStateChangeHandler((speakingState) => {
  if (speakingState.isSpeakingDetected && !volumeTimer) {
    // If someone in the meeting starts speaking, periodically
    // lower the volume using your MediaPlayerSynchronizer's
    // VolumeLimiter.
    synchronizer.volumeLimiter?.lowerVolume();
    volumeTimer = setInterval(() => {
      synchronizer.volumeLimiter?.lowerVolume();
    }, 250);
  } else if (volumeTimer) {
    // If everyone in the meeting stops speaking and the
    // interval timer is active, clear the interval.
    clearInterval(volumeTimer);
    volumeTimer = undefined;
  }
});

import { meeting } from "@microsoft/teams-js";

// ... set up MediaPlayerSynchronizer

// Register speaking state change handler through TeamsJS library
let volumeTimer: NodeJS.Timeout | undefined;
meeting.registerSpeakingStateChangeHandler((speakingState: meeting.ISpeakingState) => {
  if (speakingState.isSpeakingDetected && !volumeTimer) {
    // If someone in the meeting starts speaking, periodically
    // lower the volume using your MediaPlayerSynchronizer's
    // VolumeLimiter.
    synchronizer.volumeLimiter?.lowerVolume();
    volumeTimer = setInterval(() => {
      synchronizer.volumeLimiter?.lowerVolume();
    }, 250);
  } else if (volumeTimer) {
    // If everyone in the meeting stops speaking and the
    // interval timer is active, clear the interval.
    clearInterval(volumeTimer);
    volumeTimer = undefined;
  }
});

import { useMediaSynchronizer } from "@microsoft/live-share-react";
import { meeting } from "@microsoft/teams-js";
import { useRef, useEffect } from "react";

// Define a unique key that distinguishes this `useMediaSynchronizer` from others in your app
const UNIQUE_KEY = "MEDIA-SESSION-ID";

// Example component
export function VideoPlayer() {
    const videoRef = useRef(null);
    const { synchronizer } = useMediaSynchronizer(
        UNIQUE_KEY,
        videoRef,
        "<YOUR_INITIAL_VIDEO_URL>",
    );

    const enableSmartSound = () => {
        let volumeTimer;
        meeting.registerSpeakingStateChangeHandler((speakingState) => {
            if (speakingState.isSpeakingDetected && !volumeTimer) {
                // If someone in the meeting starts speaking, periodically
                // lower the volume using your MediaPlayerSynchronizer's
                // VolumeLimiter.
                synchronizer.volumeLimiter?.lowerVolume();
                volumeTimer = setInterval(() => {
                    synchronizer.volumeLimiter?.lowerVolume();
                }, 250);
            } else if (volumeTimer) {
                // If everyone in the meeting stops speaking and the
                // interval timer is active, clear the interval.
                clearInterval(volumeTimer);
                volumeTimer = undefined;
            }
        });
    }

    return (
        <div>
            <video ref={videoRef} />
            <button onClick={enableSmartSound}>
                Enable smart sound
            </button>
        </div>
      );
}

此外，将以下 RSC 权限添加到应用清单中：

{
  // ...rest of your manifest here
  "authorization": {
    "permissions": {
      "resourceSpecific": [
        // ...other permissions here
        {
          "name": "OnlineMeetingIncomingAudio.Detect.Chat",
          "type": "Delegated"
        },
        {
          "name": "OnlineMeetingIncomingAudio.Detect.Group",
          "type": "Delegated"
        }
      ]
    }
  }
}

注意

用于音频躲避的 registerSpeakingStateChangeHandler API 目前仅适用于 Microsoft Teams 桌面版以及计划会议类型和会议类型。

代码示例

示例名称	Description	JavaScript	TypeScript
React 视频	显示 LiveMediaSession 对象如何与 HTML5 视频配合使用的基本示例。	View	不适用
React 媒体模板	使所有连接的客户端能够一起观看视频、生成共享播放列表、转移在控制的人，并通过视频进行批注。	View	View

后续步骤

Live Share 画布

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安装

媒体同步概述

挂起和等待点

音频闪避

代码示例

后续步骤

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