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远程VideoStream无法与WebRTC一起使用

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编辑:我写了一个详细的教程,解释如何构建一个简单的Videochat应用程序,包括一个信号服务器:

教程:使用HTML和JavaScript创建自己的Videochat-Application

如果您觉得它有用且易于理解,请告诉我 . 谢谢!


我试图让Streams通过WebRTC和Websocket(nodejs-server)工作 . 据我所知,通过SDP的握手工作,并 Build 了Peerconnection . 问题是 - 远程视频没有播放 . src-Attribute获取了Blob并设置了自动播放,但它只是不会播放 . 也许我对ICE候选人做错了(它们用于媒体流,对吧?) . 有没有办法检查PeerConnection是否设置正确?

编辑:也许我应该解释代码是如何工作的

  • 在网站加载时 Build 与websocket-server的连接,创建使用谷歌STUN服务器的PeerConnection,并收集视频和音频流并将其添加到PeerConnection

  • 当一个用户点击“创建商品”时 - 按钮将包含其会话描述(SDP)的消息发送到服务器(客户端功能sendOffer()),该服务器将其广播给其他用户

  • 其他用户获取消息并保存他收到的SDP

  • 如果用户单击“接受要约”,则SDP将添加到RemoteDescription(func createAnswer()),然后向提供用户发送应答消息(包含应答用户的SDP)

  • 在产品用户端执行func offerAccepted(),将其他用户的SDP添加到他的RemoteDesription中 .

我不确定在什么时候确切地调用了icecandidate处理程序,但我认为它们应该可以正常工作,因为我在两侧都有两个日志 .

这是我的代码(这仅用于测试,所以即使有一个叫做广播的功能,也意味着一次只有2个用户可以在同一个网站上):

Markup of index.html:

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <style>
            #acceptOffer  {
                display: none;
            }
        </style>
    </head>
    <body>
        <h2>Chat</h2>
        <div>
            <textarea class="output" name="" id="" cols="30" rows="10"></textarea>
        </div>
        <button id="createOffer">create Offer</button>
        <button id="acceptOffer">accept Offer</button>

        <h2>My Stream</h2>
        <video id="myStream" autoplay src=""></video>
        <h2>Remote Stream</h2>
        <video id="remoteStream" autoplay src=""></video>

        <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
        <script src="websocketClient.js"></script>
</body>
</html>

Here is the Server-Code:

"use strict";

var webSocketsServerPort = 61122;

var webSocketServer = require('websocket').server,
http = require('http'),
clients = [];


var server = http.createServer(function(request, response) {
    // Not important for us. We're writing WebSocket server, not HTTP server
});
server.listen(webSocketsServerPort, function() {
    console.log((new Date()) + " Server is listening on port " + webSocketsServerPort);
});

var wsServer = new webSocketServer({
    httpServer: server
});

wsServer.on('request', function(request) {
    console.log((new Date()) + ' Connection from origin ' + request.origin + '.');

    var connection = request.accept(null, request.origin),
    index = clients.push(connection) - 1,
    userName=false;
    console.log((new Date()) + ' Connection accepted from '+connection.remoteAddress);

    // user sent some message
    connection.on('message', function(message) {
        var json = JSON.parse(message.utf8Data);

        console.log(json.type);
        switch (json.type) {
            case 'broadcast':
                broadcast(json);
            break;

            case 'emit':
                emit({type:'offer', data:json.data.data});
            break;

            case 'client':
                respondToClient(json, clients[index]);
            break;

            default:
                respondToClient({type:'error', data:'Sorry, i dont understand that.'}, clients[index]);
            break;

        }

    });

    connection.on('close', function(connection) {
        clients.splice(index,1);
        console.log((new Date()) + " Peer " + connection.remoteAddress + " disconnected.");
        broadcast({type:'text', data: userName+' has left the channel.'});
    });

    var respondToClient = function(data, client){
        client.sendUTF(JSON.stringify( data ));
    };

    var broadcast = function(data){
        for(var i = 0; i < clients.length; i++ ) {
            if(i != index ) {
                clients[i].sendUTF(JSON.stringify( data ));
            }
        }
    };
    var emit = function(){
        // TBD
    };
});

And here the Client-Code:

$(function () {
    "use strict";

    /**
    * Websocket Stuff
    **/

    window.WebSocket = window.WebSocket || window.MozWebSocket;

    // open connection
    var connection = new WebSocket('ws://url-to-node-server:61122'),
    myName = false,
    mySDP = false,
    otherSDP = false;

    connection.onopen = function () {
        console.log("connection to WebSocketServer successfull");
    };

    connection.onerror = function (error) {
        console.log("WebSocket connection error");
    };

    connection.onmessage = function (message) {
        try {
            var json = JSON.parse(message.data),
            output = document.getElementsByClassName('output')[0];

            switch(json.callback) {
                case 'offer':
                    otherSDP = json.data;
                    document.getElementById('acceptOffer').style.display = 'block';
                break;

                case 'setIceCandidate':
                console.log('ICE CANDITATE ADDED');
                    peerConnection.addIceCandidate(json.data);
                break;

                case 'text':
                    var text = output.value;
                    output.value = json.data+'\n'+output.value;
                break;

                case 'answer':
                    otherSDP = json.data;
                    offerAccepted();
                break;

            }

        } catch (e) {
            console.log('This doesn\'t look like a valid JSON or something else went wrong.');
            return;
        }
    };
    /**
    * P2P Stuff
    **/
    navigator.getMedia = ( navigator.getUserMedia ||
       navigator.webkitGetUserMedia ||
       navigator.mozGetUserMedia ||
       navigator.msGetUserMedia);

    // create Connection
    var peerConnection = new webkitRTCPeerConnection(
        { "iceServers": [{ "url": "stun:stun.l.google.com:19302" }] }
    );


    var remoteVideo = document.getElementById('remoteStream'),
        myVideo = document.getElementById('myStream'),

        // get local video-Stream and add to Peerconnection
        stream = navigator.webkitGetUserMedia({ audio: false, video: true }, function (stream) {
            myVideo.src = webkitURL.createObjectURL(stream);
            console.log(stream);
            peerConnection.addStream(stream);
    });

    // executes if other side adds stream
    peerConnection.onaddstream = function(e){
        console.log("stream added");
        if (!e)
        {
            return;
        }
        remoteVideo.setAttribute("src",URL.createObjectURL(e.stream));
        console.log(e.stream);
    };

    // executes if my icecandidate is received, then send it to other side
    peerConnection.onicecandidate  = function(candidate){
        console.log('ICE CANDITATE RECEIVED');
        var json = JSON.stringify( { type: 'broadcast', callback:'setIceCandidate', data:candidate});
        connection.send(json);
    };

    // send offer via Websocket
    var sendOffer = function(){
        peerConnection.createOffer(function (sessionDescription) {
            peerConnection.setLocalDescription(sessionDescription);
            // POST-Offer-SDP-For-Other-Peer(sessionDescription.sdp, sessionDescription.type);
            var json = JSON.stringify( { type: 'broadcast', callback:'offer',data:{sdp:sessionDescription.sdp,type:'offer'}});
            connection.send(json);

        }, null, { 'mandatory': { 'OfferToReceiveAudio': true, 'OfferToReceiveVideo': true } });
    };

    // executes if offer is received and has been accepted
    var createAnswer = function(){

        peerConnection.setRemoteDescription(new RTCSessionDescription(otherSDP));

        peerConnection.createAnswer(function (sessionDescription) {
            peerConnection.setLocalDescription(sessionDescription);
            // POST-answer-SDP-back-to-Offerer(sessionDescription.sdp, sessionDescription.type);
            var json = JSON.stringify( { type: 'broadcast', callback:'answer',data:{sdp:sessionDescription.sdp,type:'answer'}});
            connection.send(json);
        }, null, { 'mandatory': { 'OfferToReceiveAudio': true, 'OfferToReceiveVideo': true } });

    };

    // executes if other side accepted my offer
    var offerAccepted = function(){
        peerConnection.setRemoteDescription(new RTCSessionDescription(otherSDP));
        console.log('it should work now');
    };

    $('#acceptOffer').on('click',function(){
        createAnswer();
    });

    $('#createOffer').on('click',function(){
        sendOffer();
    });
});

我还读到在发送任何报价之前必须收集本地媒体流 . 这是否意味着我必须在创建PeerConnection时添加它?即像这样的东西:

// create Connection
var peerConnection = new webkitRTCPeerConnection(
    { 
        "iceServers": [{ "url": "stun:stun.l.google.com:19302" }],
        "mediaStream": stream // attach media stream here?
    }
);

在此先感谢,我感谢任何帮助!

EDIT2: 我现在更进一步了 . 由于"An invalid or illegal string was specified. ",似乎添加远程ice-candidate(在客户端代码中为switch-case setIceCandidate)无效 . json.data.candidate-object如下所示:

candidate: "a=candidate:1663431597 2 udp 1845501695 141.84.69.86 57538 typ srflx raddr 10.150.16.92 rport 57538 generation 0
↵"
sdpMLineIndex: 1
sdpMid: "video"

我试着像这样创造一个新的候选人

var remoteCandidate = new RTCIceCandidate(json.data.candidate);
 peerConnection.addIceCandidate(remoteCandidate);

但我仍然有语法错误

1 回答

  • 21

    我最近遇到了基本相同的问题,我在这里得到的最好的建议是创建我的程序版本,我手动复制并粘贴来自一个“同行”的SDP和ICE信息(即,浏览器标签)到另一个,反之亦然 .

    通过这样做,我意识到了几件事:

    • 您必须调用对等连接对象 before 的addStream方法,并尝试创建任何要约/答案 .

    • 在调用createOffer或createAnswer方法时,会立即生成该客户端的ICE候选项 . 但是,一旦您将ICE信息发送给另一个对等方,您就无法在设置远程描述之后(通过使用收到的要约/回答)实际设置ICE信息 .

    • 确保您正确编码了有关要在线路上发送的所有信息 . 在JS中,这意味着您应该对要在线路上发送的所有数据使用encodeURIComponent函数 . 我有一个问题,其中SDP和ICE信息有时会被正确设置,有时不会 . 这与我不是对数据进行URI编码这一事实有关,这导致数据中的任何加号被转换为空格,这使得一切都搞砸了 .

    无论如何,就像我说的,我建议创建一个程序版本,其中有一堆文本区域可以将所有数据吐出到屏幕上,然后有其他文本区域可以粘贴复制数据以便将其设置为另一个同行 .
    这样做真的澄清了整个WebRTC流程,老实说,在我见过的任何文档/教程中都没有很好地解释 .

    祝你好运,如果我能帮助我,请告诉我 .

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