我正在重新发布这个问题,因为我之前没有得到有效的解决方案。对带来的麻烦表示抱歉。我已经在 heroku 上的 codelab webrtc 演示教程的第 6 步中托管了示例(使用 node.js 进行信号发送的基本视频聊天应用程序),以尝试在不同的网络中使用它。我正在为此使用 Xirsys STUN/TURN 服务器。当 2 个系统在同一个网络上时,它可以正常工作。但是当我尝试通过不同的网络连接系统时,它在远程视频上显示黑屏。我无法在这里找出问题所在。我附上了 main.js 的代码。感谢您的帮助。
'use strict';
var isChannelReady;
var isInitiator = false;
var isStarted = false;
var localStream;
var pc;
var remoteStream;
var turnReady;
var pc_config = {'iceServers': [
{url:'stun:turn02.uswest.xirsys.com'},
{
url: 'turn:turn02.uswest.xirsys.com:443?transport=udp',
credential: 'my_credentials',
username: 'my_username'
},
{
url: 'turn:turn02.uswest.xirsys.com:443?transport=tcp',
credential: 'my_credentials',
username: 'my_username'
},
{
url: 'turn:turn02.uswest.xirsys.com:5349?transport=udp',
credential: 'my_credentials',
username: 'my_username'
},
{
url: 'turn:turn02.uswest.xirsys.com:5349?transport=tcp',
credential: 'my_credentials',
username: 'my_username'
}
]};
var pc_constraints = {'optional': [{'DtlsSrtpKeyAgreement': true}]};
// Set up audio and video regardless of what devices are present.
var sdpConstraints = {'mandatory': {
'OfferToReceiveAudio':true,
'OfferToReceiveVideo':true }};
/////////////////////////////////////////////
var room = location.pathname.substring(1);
if (room === '') {
room = prompt('Enter room name:');
// room = 'fool';
} else {
//
}
var socket = io.connect();
if (room !== '') {
console.log('Create or join room', room);
socket.emit('create or join', room);
}
socket.on('created', function (room){
console.log('Created room ' + room);
isInitiator = true;
});
socket.on('full', function (room){
console.log('Room ' + room + ' is full');
});
socket.on('join', function (room){
console.log('Another peer made a request to join room ' + room);
console.log('This peer is the initiator of room ' + room + '!');
isChannelReady = true;
});
socket.on('joined', function (room){
console.log('This peer has joined room ' + room);
isChannelReady = true;
});
socket.on('log', function (array){
console.log.apply(console, array);
});
////////////////////////////////////////////////
function sendMessage(message){
console.log('Client sending message: ', message);
// if (typeof message === 'object') {
// message = JSON.stringify(message);
// }
socket.emit('message', message);
}
socket.on('message', function (message){
console.log('Client received message:', message);
if (message === 'got user media') {
maybeStart();
} else if (message.type === 'offer') {
if (!isInitiator && !isStarted) {
maybeStart();
}
pc.setRemoteDescription(new RTCSessionDescription(message));
doAnswer();
} else if (message.type === 'answer' && isStarted) {
pc.setRemoteDescription(new RTCSessionDescription(message));
} else if (message.type === 'candidate' && isStarted) {
var candidate = new RTCIceCandidate({
sdpMLineIndex: message.label,
candidate: message.candidate
});
pc.addIceCandidate(candidate);
} else if (message === 'bye' && isStarted) {
handleRemoteHangup();
}
});
////////////////////////////////////////////////////
var localVideo = document.querySelector('#localVideo');
var remoteVideo = document.querySelector('#remoteVideo');
function handleUserMedia(stream) {
console.log('Adding local stream.');
localVideo.src = window.URL.createObjectURL(stream);
localStream = stream;
sendMessage('got user media');
if (isInitiator) {
maybeStart();
}
}
function handleUserMediaError(error){
console.log('getUserMedia error: ', error);
}
var constraints = {video: true};
getUserMedia(constraints, handleUserMedia, handleUserMediaError);
console.log('Getting user media with constraints', constraints);
// if (location.hostname != "localhost") {
// requestTurn('https://computeengineondemand.appspot.com/turn?username=41784574&key=4080218913');
// }
function maybeStart() {
if (!isStarted && typeof localStream != 'undefined' && isChannelReady) {
createPeerConnection();
pc.addStream(localStream);
isStarted = true;
console.log('isInitiator', isInitiator);
if (isInitiator) {
doCall();
}
}
}
window.onbeforeunload = function(e){
sendMessage('bye');
}
/////////////////////////////////////////////////////////
function createPeerConnection() {
try {
pc = new RTCPeerConnection(null);
pc.onicecandidate = handleIceCandidate;
pc.onaddstream = handleRemoteStreamAdded;
pc.onremovestream = handleRemoteStreamRemoved;
console.log('Created RTCPeerConnnection');
} catch (e) {
console.log('Failed to create PeerConnection, exception: ' + e.message);
alert('Cannot create RTCPeerConnection object.');
return;
}
}
function handleIceCandidate(event) {
console.log('handleIceCandidate event: ', event);
if (event.candidate) {
sendMessage({
type: 'candidate',
label: event.candidate.sdpMLineIndex,
id: event.candidate.sdpMid,
candidate: event.candidate.candidate});
} else {
console.log('End of candidates.');
}
}
function handleRemoteStreamAdded(event) {
console.log('Remote stream added.');
remoteVideo.src = window.URL.createObjectURL(event.stream);
remoteStream = event.stream;
}
function handleCreateOfferError(event){
console.log('createOffer() error: ', e);
}
function doCall() {
console.log('Sending offer to peer');
pc.createOffer(setLocalAndSendMessage, handleCreateOfferError);
}
function doAnswer() {
console.log('Sending answer to peer.');
pc.createAnswer(setLocalAndSendMessage, null, sdpConstraints);
}
function setLocalAndSendMessage(sessionDescription) {
// Set Opus as the preferred codec in SDP if Opus is present.
sessionDescription.sdp = preferOpus(sessionDescription.sdp);
pc.setLocalDescription(sessionDescription);
console.log('setLocalAndSendMessage sending message' , sessionDescription);
sendMessage(sessionDescription);
}
function requestTurn(turn_url) {
var turnExists = false;
for (var i in pc_config.iceServers) {
if (pc_config.iceServers[i].url.substr(0, 5) === 'turn:') {
turnExists = true;
turnReady = true;
break;
}
}
if (!turnExists) {
console.log('Getting TURN server from ', turn_url);
// No TURN server. Get one from computeengineondemand.appspot.com:
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function(){
if (xhr.readyState === 4 && xhr.status === 200) {
var turnServer = JSON.parse(xhr.responseText);
console.log('Got TURN server: ', turnServer);
pc_config.iceServers.push({
'url': 'turn:' + turnServer.username + '@' + turnServer.turn,
'credential': turnServer.password
});
turnReady = true;
}
};
xhr.open('GET', turn_url, true);
xhr.send();
}
}
function handleRemoteStreamAdded(event) {
console.log('Remote stream added.');
remoteVideo.src = window.URL.createObjectURL(event.stream);
remoteStream = event.stream;
}
function handleRemoteStreamRemoved(event) {
console.log('Remote stream removed. Event: ', event);
}
function hangup() {
console.log('Hanging up.');
stop();
sendMessage('bye');
}
function handleRemoteHangup() {
// console.log('Session terminated.');
// stop();
// isInitiator = false;
}
function stop() {
isStarted = false;
// isAudioMuted = false;
// isVideoMuted = false;
pc.close();
pc = null;
}
///////////////////////////////////////////
// Set Opus as the default audio codec if it's present.
function preferOpus(sdp) {
var sdpLines = sdp.split('\r\n');
var mLineIndex=null;
// Search for m line.
for (var i = 0; i < sdpLines.length; i++) {
if (sdpLines[i].search('m=audio') !== -1) {
mLineIndex = i;
break;
}
}
if (mLineIndex === null) {
return sdp;
}
// If Opus is available, set it as the default in m line.
for (i = 0; i < sdpLines.length; i++) {
if (sdpLines[i].search('opus/48000') !== -1) {
var opusPayload = extractSdp(sdpLines[i], /:(\d+) opus\/48000/i);
if (opusPayload) {
sdpLines[mLineIndex] = setDefaultCodec(sdpLines[mLineIndex], opusPayload);
}
break;
}
}
// Remove CN in m line and sdp.
sdpLines = removeCN(sdpLines, mLineIndex);
sdp = sdpLines.join('\r\n');
return sdp;
}
function extractSdp(sdpLine, pattern) {
var result = sdpLine.match(pattern);
return result && result.length === 2 ? result[1] : null;
}
// Set the selected codec to the first in m line.
function setDefaultCodec(mLine, payload) {
var elements = mLine.split(' ');
var newLine = [];
var index = 0;
for (var i = 0; i < elements.length; i++) {
if (index === 3) { // Format of media starts from the fourth.
newLine[index++] = payload; // Put target payload to the first.
}
if (elements[i] !== payload) {
newLine[index++] = elements[i];
}
}
return newLine.join(' ');
}
// Strip CN from sdp before CN constraints is ready.
function removeCN(sdpLines, mLineIndex) {
var mLineElements = sdpLines[mLineIndex].split(' ');
// Scan from end for the convenience of removing an item.
for (var i = sdpLines.length-1; i >= 0; i--) {
var payload = extractSdp(sdpLines[i], /a=rtpmap:(\d+) CN\/\d+/i);
if (payload) {
var cnPos = mLineElements.indexOf(payload);
if (cnPos !== -1) {
// Remove CN payload from m line.
mLineElements.splice(cnPos, 1);
}
// Remove CN line in sdp
sdpLines.splice(i, 1);
}
}
sdpLines[mLineIndex] = mLineElements.join(' ');
return sdpLines;
}