视频互动直播是当前比较热门的玩法，我们经常见到有 PK 连麦、直播答题、一起 KTV 、电商直播、互动大班课、视频相亲等。本文将演示如何通过声网 视频 SDK 在 Web 端实现一个视频直播应用。话不多说，我们开始动手实操。
在声网开发者控制台 Console https://console.agora.io 注册声网开发者账号后，需要获取项目 AppID 。另外，开发者每个月可获得 10000 分钟的免费使用额度，可实现各类实时音视频场景。
我们在 GitHub 上提供一个开源的基础视频通话示例项目，在开始开发之前你可以通过该示例项目体验音视频通话效果。
从 Web 前端页面引入声网 SDK ，发起视频通话。
声网 SDK 的兼容性良好，对硬件设备和软件系统的要求不高，开发环境和测试环境满足以下条件即可，以下是本文的开发环境和测试环境：
实现视频通话之前，参考如下步骤设置你的项目： 如需创建新项目，可以在 Visual Studio Code 里 File > New Window ，创建 Web 项目。完整的目录结构如下，根据个人经验会有所变化。
.
├── index.css # 用于设计 Web 应用的用户界面样式
├── index.html # 用于设计 Web 应用的用户界面
├── index.js # 通过 AgoraRTCClient 实现具体应用逻辑的代码。
└── vendor # 第三方前端插件，辅助页面布局和交互，本教程中是下载到本地使用，你也可以使用 CDN 的方式
├── bootstrap.bundle.min.js
├── bootstrap.min.css
└── jquery-3.4.1.min.js
声网可以下载到本地使用，也可以直接使用声网的 CDN 引入， 本文推荐使用 CDN 方式集成 Agora SDK 。
在 index.html 中添加以下代码
<!DOCTYPE html>
...
<link rel="stylesheet" href="./vendor/bootstrap.min.css">
<link rel="stylesheet" href="./index.css">
...
<script src="./vendor/jquery-3.4.1.min.js"></script>
<script src="./vendor/bootstrap.bundle.min.js"></script>
<script src="https://download.agora.io/sdk/release/AgoraRTC_N.js"></script>
<script src="./index.js"></script>
...
可以直接复制运行。
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Basic Video Call -- Agora</title>
<link rel="stylesheet" href="./vendor/bootstrap.min.css">
<link rel="stylesheet" href="./index.css">
</head>
<body>
<div class="container-fluid banner">
<p class="banner-text">Basic Video Call</p>
<a style="color: rgb(255, 255, 255);fill: rgb(255, 255, 255);fill-rule: evenodd; position: absolute; right: 10px; top: 4px;"
class="Header-link " href="https://github.com/AgoraIO-Community/AgoraWebSDK-NG/tree/master/Demo">
<svg class="octicon octicon-mark-github v-align-middle" height="32" viewBox="0 0 16 16" version="1.1" width="32" aria-hidden="true"><path fill-rule="evenodd" d="M8 0C3.58 0 0 3.58 0 8c0 3.54 2.29 6.53 5.47 7.59.4.07.55-.17.55-.38 0-.19-.01-.82-.01-1.49-2.01.37-2.53-.49-2.69-.94-.09-.23-.48-.94-.82-1.13-.28-.15-.68-.52-.01-.53.63-.01 1.08.58 1.23.82.72 1.21 1.87.87 2.33.66.07-.52.28-.87.51-1.07-1.78-.2-3.64-.89-3.64-3.95 0-.87.31-1.59.82-2.15-.08-.2-.36-1.02.08-2.12 0 0 .67-.21 2.2.82.64-.18 1.32-.27 2-.27.68 0 1.36.09 2 .27 1.53-1.04 2.2-.82 2.2-.82.44 1.1.16 1.92.08 2.12.51.56.82 1.27.82 2.15 0 3.07-1.87 3.75-3.65 3.95.29.25.54.73.54 1.48 0 1.07-.01 1.93-.01 2.2 0 .21.15.46.55.38A8.013 8.013 0 0016 8c0-4.42-3.58-8-8-8z"></path></svg>
</a>
</div>
<div id="success-alert" class="alert alert-success alert-dismissible fade show" role="alert">
<strong>Congratulations!</strong><span> You can invite others join this channel by click </span><a href="" target="_blank">here</a>
<button type="button" class="close" data-dismiss="alert" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
<div id="success-alert-with-token" class="alert alert-success alert-dismissible fade show" role="alert">
<strong>Congratulations!</strong><span> Joined room successfully. </span>
<button type="button" class="close" data-dismiss="alert" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
<div id="success-alert-with-token" class="alert alert-success alert-dismissible fade show" role="alert">
<strong>Congratulations!</strong><span> Joined room successfully. </span>
<button type="button" class="close" data-dismiss="alert" aria-label="Close">
<span aria-hidden="true">×</span>
</button>
</div>
<div class="container">
<form id="join-form">
<div class="row join-info-group">
<div class="col-sm">
<p class="join-info-text">AppID</p>
<input id="appid" type="text" placeholder="enter appid" required>
<p class="tips">If you don`t know what is your appid, checkout <a href="https://docs.agora.io/en/Agora%20Platform/terms?platform=All%20Platforms#a-nameappidaapp-id">this</a></p>
</div>
<div class="col-sm">
<p class="join-info-text">Token(optional)</p>
<input id="token" type="text" placeholder="enter token">
<p class="tips">If you don`t know what is your token, checkout <a href="https://docs.agora.io/en/Agora%20Platform/terms?platform=All%20Platforms#a-namekeyadynamic-key">this</a></p>
</div>
<div class="col-sm">
<p class="join-info-text">Channel</p>
<input id="channel" type="text" placeholder="enter channel name" required>
<p class="tips">If you don`t know what is your channel, checkout <a href="https://docs.agora.io/en/Agora%20Platform/terms?platform=All%20Platforms#channel">this</a></p>
</div>
</div>
<div class="button-group">
<button id="join" type="submit" class="btn btn-primary btn-sm">Join</button>
<button id="leave" type="button" class="btn btn-primary btn-sm" disabled>Leave</button>
</div>
</form>
<div class="row video-group">
<div class="col">
<p id="local-player-name" class="player-name"></p>
<div id="local-player" class="player"></div>
</div>
<div class="w-100"></div>
<div class="col">
<div id="remote-playerlist"></div>
</div>
</div>
</div>
<script src="./vendor/jquery-3.4.1.min.js"></script>
<script src="./vendor/bootstrap.bundle.min.js"></script>
<script src="https://download.agora.io/sdk/release/AgoraRTC_N.js"></script>
<script src="./index.js"></script>
</body>
</html>
注：以下代码都将在 index.js 中添加
var client = AgoraRTC.createClient({ mode: "rtc", codec: "vp8" });
// Join a channel and create local tracks. Best practice is to use Promise.all and run them concurrently.
[ options.uid, localTracks.audioTrack, localTracks.videoTrack ] = await Promise.all([
// Join the channel.
client.join(options.appid, options.channel, options.token || null, options.uid || null),
// Create tracks to the local microphone and camera.
AgoraRTC.createMicrophoneAudioTrack(),
AgoraRTC.createCameraVideoTrack()
]);
// Play the local video track to the local browser and update the UI with the user ID.
localTracks.videoTrack.play("local-player");
// Publish the local video and audio tracks to the channel.
await client.publish(Object.values(localTracks));
// Add an event listener to play remote tracks when remote user publishes.
client.on("user-published", handleUserPublished);
client.on("user-unpublished", handleUserUnpublished);
function handleUserPublished(user, mediaType) {
const id = user.uid;
remoteUsers[id] = user;
subscribe(user, mediaType);
}
function handleUserUnpublished(user, mediaType) {
if (mediaType === 'video') {
const id = user.uid;
delete remoteUsers[id];
$(`#player-wrapper-${id}`).remove();
}
}
async function subscribe(user, mediaType) {
const uid = user.uid;
// subscribe to a remote user
await client.subscribe(user, mediaType);
console.log("subscribe success");
if (mediaType === 'video') {
const player = $(`
<div id="player-wrapper-${uid}">
<p class="player-name">remoteUser(${uid})</p>
<div id="player-${uid}" class="player"></div>
</div>
`);
$("#remote-playerlist").append(player);
user.videoTrack.play(`player-${uid}`);
}
if (mediaType === 'audio') {
user.audioTrack.play();
}
}
async function leave() {
for (trackName in localTracks) {
var track = localTracks[trackName];
if(track) {
track.stop();
track.close();
localTracks[trackName] = undefined;
}
}
// Remove remote users and player views.
remoteUsers = {};
$("#remote-playerlist").html("");
// leave the channel
await client.leave();
}
// create Agora client
var client = AgoraRTC.createClient({ mode: "rtc", codec: "vp8" });
var localTracks = {
videoTrack: null,
audioTrack: null
};
var remoteUsers = {};
// Agora client options
var options = {
appid: null,
channel: null,
uid: null,
token: null
};
// the demo can auto join channel with params in url
$(() => {
var urlParams = new URL(location.href).searchParams;
options.appid = urlParams.get("appid");
options.channel = urlParams.get("channel");
options.token = urlParams.get("token");
if (options.appid && options.channel) {
$("#appid").val(options.appid);
$("#token").val(options.token);
$("#channel").val(options.channel);
$("#join-form").submit();
}
})
$("#join-form").submit(async function (e) {
e.preventDefault();
$("#join").attr("disabled", true);
try {
options.appid = $("#appid").val();
options.token = $("#token").val();
options.channel = $("#channel").val();
await join();
if(options.token) {
$("#success-alert-with-token").css("display", "block");
} else {
$("#success-alert a").attr("href", `index.html?appid=${options.appid}&channel=${options.channel}&token=${options.token}`);
$("#success-alert").css("display", "block");
}
} catch (error) {
console.error(error);
} finally {
$("#leave").attr("disabled", false);
}
})
$("#leave").click(function (e) {
leave();
})
async function join() {
// add event listener to play remote tracks when remote user publishs.
client.on("user-published", handleUserPublished);
client.on("user-unpublished", handleUserUnpublished);
// join a channel and create local tracks, we can use Promise.all to run them concurrently
[ options.uid, localTracks.audioTrack, localTracks.videoTrack ] = await Promise.all([
// join the channel
client.join(options.appid, options.channel, options.token || null),
// create local tracks, using microphone and camera
AgoraRTC.createMicrophoneAudioTrack(),
AgoraRTC.createCameraVideoTrack()
]);
// play local video track
localTracks.videoTrack.play("local-player");
$("#local-player-name").text(`localVideo(${options.uid})`);
// publish local tracks to channel
await client.publish(Object.values(localTracks));
console.log("publish success");
}
async function leave() {
for (trackName in localTracks) {
var track = localTracks[trackName];
if(track) {
track.stop();
track.close();
localTracks[trackName] = undefined;
}
}
// remove remote users and player views
remoteUsers = {};
$("#remote-playerlist").html("");
// leave the channel
await client.leave();
$("#local-player-name").text("");
$("#join").attr("disabled", false);
$("#leave").attr("disabled", true);
console.log("client leaves channel success");
}
async function subscribe(user, mediaType) {
const uid = user.uid;
// subscribe to a remote user
await client.subscribe(user, mediaType);
console.log("subscribe success");
if (mediaType === 'video') {
const player = $(`
<div id="player-wrapper-${uid}">
<p class="player-name">remoteUser(${uid})</p>
<div id="player-${uid}" class="player"></div>
</div>
`);
$("#remote-playerlist").append(player);
user.videoTrack.play(`player-${uid}`);
}
if (mediaType === 'audio') {
user.audioTrack.play();
}
}
function handleUserPublished(user, mediaType) {
const id = user.uid;
remoteUsers[id] = user;
subscribe(user, mediaType);
}
function handleUserUnpublished(user) {
const id = user.uid;
delete remoteUsers[id];
$(`#player-wrapper-${id}`).remove();
}
在浏览器开两个 tab 运行网页，使用两个用户加入同一个频道，如果能看见两个自己，说明你成功了。
https://download.agora.io/sdk/release/Agora_Web_SDK_v4_14_0_FULL.zip
以上就是基于声网 Web SDK 实现一对一视频通话的全部内容。有问题欢迎到「 RTE 开发者社区」https://www.agora.io/cn/community/ 交流吐槽。
这是一个专为移动设备优化的页面（即为了让你能够在 Google 搜索结果里秒开这个页面），如果你希望参与 V2EX 社区的讨论，你可以继续到 V2EX 上打开本讨论主题的完整版本。
V2EX 是创意工作者们的社区，是一个分享自己正在做的有趣事物、交流想法，可以遇见新朋友甚至新机会的地方。
V2EX is a community of developers, designers and creative people.