javascript - WebRTC远程视频黑屏

Question

我正在尝试遵循“入门”WebRTC 指南: http://www.html5rocks.com/en/tutorials/webrtc/basics/

我想要实现的是在两个对等点之间建立视频连接。但是，当我共享网络摄像头(按 chrome 中的允许按钮)时，remoteVideo 在远程端是黑色的。

我的脚本:

var pc;
var sdpConstraints = {'mandatory': { 'OfferToReceiveAudio':true, 'OfferToReceiveVideo':true }};
var constraints = {video: true, audio: true};
var socket = io.connect();

function start(isCaller) {
    var servers = {"iceServers": [{ "url": "stun:stun.l.google.com:19302"}]};
    pc = new RTCPeerConnection(servers);

    pc.onicecandidate = function(event) {
        if(event.candidate) {
            socket.emit('candidate', {'candidate': event.candidate});
        }
    }

    pc.onaddstream = function(event) {
        attachMediaStream(remoteVideo, event.stream);
    }

    getUserMedia(constraints, function(stream) {
        attachMediaStream(localVideo, stream);
        pc.addStream(stream);

        if(isCaller) {
            pc.createOffer(gotDescription, null, sdpConstraints);
        } else {
            pc.createAnswer(pc.remoteDescription, gotDescription);
        }

        function gotDescription(desc) {
            pc.setLocalDescription(desc);
            socket.emit('sdpMessage', {'sdpMessage': desc});
        }
    }, printError);
}

socket.on('gotMessage', function(data) {
    if(!pc) { start(false); }

    if(data.remoteSDP) {
        pc.setRemoteDescription(new RTCSessionDescription(data.remoteSDP));
    } else {
        pc.addIceCandidate(new RTCIceCandidate(data.remoteCandidate), onAddIceCandidateSuccess, onAddIceCandidateError);
    }
});

HTML 包含:

<button onclick="start(true)">HIT ME</button>
<video id="localVideo" autoplay></video>
<video id="remoteVideo" autoplay></video>

部分server.js

serv_io.sockets.on('connection', function(socket) {
    socket.on('candidate', function(data) {
        socket.broadcast.emit('gotMessage', {'remoteCandidate': data.candidate});
    });

    socket.on('sdpMessage', function(data) {
        socket.broadcast.emit('gotMessage', {'remoteSDP': data.sdpMessage});
    });
}

控制台确实记录了 addIceCandidate 成功，当我在接收端记录媒体流时，它的 ID 和标签对应于发送者的 ID 和标签...

我做错了什么？

我也遇到了这个错误: “无法在‘RTCPeerConnection’上执行‘createAnswer’:作为参数 1 提供的回调不是函数。”

Answer 1

您对 API 的使用不正确。你提到的博客也有同样的错误。请查看正确的API here并查看 apprtc example .

createAnswer 签名是:

pc.createAnswer(successCallback, failureCallback, constraints);