我一直在努力解决这个问题，但我不知道出了什么问题，你们能帮帮我吗？我尝试了像这样修改的 WebRTC 代码。
- 调用者和被调用者都进入网络
- Web 将根据他们的用户名创建频道
- 呼叫者单击呼叫按钮并将消息发送到特定频道到某个用户的用户名。当呼叫者单击呼叫按钮时，他然后创建 peerConnection 并添加 localStream
- 被调用者将收到消息，该过程像 WebRTC 示例代码一样继续进行。当被调用者收到一个offer时，他会创建peerConnection并添加localStream，然后创建并发送answer
我的代码是这样的
var my_username = '{{ current_username }}';
var friend;
var localVideo;
var remoteVideo;
var localStream;
var remoteStream;
var channel;
var channelReady = false;
var pc;
var socket;
var started = false;
// Set up audio and video regardless of what devices are present.
var mediaConstraints = {'mandatory': {
'OfferToReceiveAudio':true,
'OfferToReceiveVideo':true }};
var isVideoMuted = false;
var isAudioMuted = false;
function choiceFriendInitialize() {
var choice_visible = false;
$('ul#friendlist > li').click(function(e) {
$(this).css('background-color', '#808080');
friend = $(this).text();
var choice = $('ul#choice');
choice_visible = true;
choice.css('display', 'inline-block');
choice.css('top', e.pageY);
choice.css('left', e.pageX);
});
// trigger call from here
$('li#call').click(function() {
$('ul#friendlist > li').css('background-color', 'transparent');
$('ul#choice').css('display', 'none');
choice_visible = false;
// call
maybeStart();
doCall();
});
$('li#unfriend').click(function() {
$('ul#friendlist > li').css('background-color', 'transparent');
$('ul#choice').css('display', 'none');
choice_visible = false;
});
$("body").mouseup(function(){
if (choice_visible) {
$('ul#friendlist > li').css('background-color', 'transparent');
$('ul#choice').css('display', 'none');
choice_visible = false;
}
});
}
function initialize() {
console.log("Initializing..");
choiceFriendInitialize();
localVideo = document.getElementById("localVideo");
remoteVideo = document.getElementById("remoteVideo");
openChannel();
doGetUserMedia();
}
function openChannel() {
console.log("Opening channel.");
var channel = new goog.appengine.Channel('{{ token }}');
var handler = {
'onopen': onChannelOpened,
'onmessage': onChannelMessage,
'onerror': onChannelError,
'onclose': onChannelClosed
};
socket = channel.open(handler);
}
function doGetUserMedia() {
// Call into getUserMedia via the polyfill (adapter.js).
var constraints = {"mandatory": {}, "optional": []};
try {
getUserMedia({'audio':true, 'video':constraints}, onUserMediaSuccess, onUserMediaError);
console.log("Requested access to local media with mediaConstraints:\n" + " \"" + JSON.stringify(constraints) + "\"");
} catch (e) {
alert("getUserMedia() failed. Is this a WebRTC capable browser?");
console.log("getUserMedia failed with exception: " + e.message);
}
}
function createPeerConnection() {
var pc_config = {"iceServers": [{"url": "stun:stun.l.google.com:19302"}]};
try {
// Create an RTCPeerConnection via the polyfill (adapter.js).
pc = new RTCPeerConnection(pc_config);
pc.onicecandidate = onIceCandidate;
console.log("Created RTCPeerConnnection with config:\n" + " \"" + JSON.stringify(pc_config) + "\".");
} catch (e) {
console.log("Failed to create PeerConnection, exception: " + e.message);
alert("Cannot create RTCPeerConnection object; WebRTC is not supported by this browser.");
return;
}
pc.onconnecting = onSessionConnecting;
pc.onopen = onSessionOpened;
pc.onaddstream = onRemoteStreamAdded;
pc.onremovestream = onRemoteStreamRemoved;
}
function maybeStart() {
if (!started && localStream && channelReady) {
console.log("Creating PeerConnection.");
createPeerConnection();
console.log("Adding local stream.");
pc.addStream(localStream);
started = true;
// Caller initiates offer to peer.
//if (initiator)
//doCall();
}
}
function doCall() {
console.log("Sending offer to peer.");
pc.createOffer(setLocalAndSendMessage, null, mediaConstraints);
}
function doAnswer() {
console.log("Sending answer to peer.");
pc.createAnswer(setLocalAndSendMessage, null, mediaConstraints);
}
function setLocalAndSendMessage(sessionDescription) {
// Set Opus as the preferred codec in SDP if Opus is present.
sessionDescription.sdp = preferOpus(sessionDescription.sdp);
pc.setLocalDescription(sessionDescription);
sendMessage({from: my_username, to: friend}, sessionDescription);
}
function sendMessage(client, message) {
console.log('C->S: ' + JSON.stringify(message));
var xhr = new XMLHttpRequest();
xhr.open('POST', '/send', true);
xhr.setRequestHeader("Content-type","application/json");
var msgString = {send_info: client, data_message: message};
xhr.send(JSON.stringify(msgString));
}
function processSignalingMessage(message) {
var msg = JSON.parse(message);
var data_message = msg.data_message;
var send_info = msg.send_info;
if (data_message.type === 'offer') {
// Callee creates PeerConnection
if (!started)
maybeStart();
pc.setRemoteDescription(new RTCSessionDescription(data_message));
friend = send_info.from;
doAnswer();
} else if (data_message.type === 'answer' && started) {
pc.setRemoteDescription(new RTCSessionDescription(data_message));
} else if (data_message.type === 'candidate' && started) {
var candidate = new RTCIceCandidate({sdpMLineIndex:data_message.label, candidate:data_message.candidate});
pc.addIceCandidate(candidate);
} else if (data_message.type === 'bye' && started) {
onRemoteHangup();
}
}
function onChannelOpened() {
console.log('Channel opened.');
channelReady = true;
}
function onChannelMessage(message) {
console.log('S->C: ' + message.data);
processSignalingMessage(message.data);
}
function onChannelError() {
console.log('Channel error.');
}
function onChannelClosed() {
console.log('Channel closed.');
}
function onUserMediaSuccess(stream) {
console.log("User has granted access to local media.");
// Call the polyfill wrapper to attach the media stream to this element.
attachMediaStream(localVideo, stream);
localVideo.style.opacity = 1;
localStream = stream;
// Caller creates PeerConnection.
//if (initiator) maybeStart();
}
function onUserMediaError(error) {
console.log("Failed to get access to local media. Error code was " + error.code);
alert("Failed to get access to local media. Error code was " + error.code + ".");
}
function onIceCandidate(event) {
if (event.candidate) {
sendMessage({from: my_username, to: friend}, {type: 'candidate',
label: event.candidate.sdpMLineIndex,
id: event.candidate.sdpMid,
candidate: event.candidate.candidate});
} else {
console.log("End of candidates.");
}
}
function onSessionConnecting(message) {
console.log("Session connecting.");
}
function onSessionOpened(message) {
console.log("Session opened.");
}
function onRemoteStreamAdded(event) {
console.log("Remote stream added.");
attachMediaStream(remoteVideo, event.stream);
remoteStream = event.stream;
waitForRemoteVideo();
}
function onRemoteStreamRemoved(event) {
console.log("Remote stream removed.");
}
function onHangup() {
console.log("Hanging up.");
transitionToDone();
stop();
// will trigger BYE from server
socket.close();
}
function onRemoteHangup() {
console.log('Session terminated.');
transitionToWaiting();
stop();
}
function stop() {
started = false;
isAudioMuted = false;
isVideoMuted = false;
pc.close();
pc = null;
}
function waitForRemoteVideo() {
if (remoteStream.videoTracks.length === 0 || remoteVideo.currentTime > 0) {
console.log('ada remote stream');
transitionToActive();
} else {
console.log('ga ada remote stream');
setTimeout(waitForRemoteVideo, 100);
}
}
function transitionToActive() {
remoteVideo.style.opacity = 1;
}
function transitionToWaiting() {
remoteVideo.style.opacity = 0;
}
function transitionToDone() {
localVideo.style.opacity = 0;
remoteVideo.style.opacity = 0;
}
function toggleVideoMute() {
if (localStream.videoTracks.length === 0) {
console.log("No local video available.");
return;
}
if (isVideoMuted) {
for (i = 0; i < localStream.videoTracks.length; i++) {
localStream.videoTracks[i].enabled = true;
}
console.log("Video unmuted.");
} else {
for (i = 0; i < localStream.videoTracks.length; i++) {
localStream.videoTracks[i].enabled = false;
}
console.log("Video muted.");
}
isVideoMuted = !isVideoMuted;
}
function toggleAudioMute() {
if (localStream.audioTracks.length === 0) {
console.log("No local audio available.");
return;
}
if (isAudioMuted) {
for (i = 0; i < localStream.audioTracks.length; i++) {
localStream.audioTracks[i].enabled = true;
}
console.log("Audio unmuted.");
} else {
for (i = 0; i < localStream.audioTracks.length; i++){
localStream.audioTracks[i].enabled = false;
}
console.log("Audio muted.");
}
isAudioMuted = !isAudioMuted;
}
setTimeout(initialize, 1);
// Send BYE on refreshing(or leaving) a demo page
// to ensure the room is cleaned for next session.
window.onbeforeunload = function() {
sendMessage({from: my_username, to: friend}, {type: 'bye'});
//Delay 100ms to ensure 'bye' arrives first.
setTimeout(function(){}, 100);
}
// Ctrl-D: toggle audio mute; Ctrl-E: toggle video mute.
// On Mac, Command key is instead of Ctrl.
// Return false to screen out original Chrome shortcuts.
document.onkeydown = function() {
if (navigator.appVersion.indexOf("Mac") != -1) {
if (event.metaKey && event.keyCode === 68) {
toggleAudioMute();
return false;
}
if (event.metaKey && event.keyCode === 69) {
toggleVideoMute();
return false;
}
} else {
if (event.ctrlKey && event.keyCode === 68) {
toggleAudioMute();
return false;
}
if (event.ctrlKey && event.keyCode === 69) {
toggleVideoMute();
return false;
}
}
}
// Set Opus as the default audio codec if it's present.
function preferOpus(sdp) {
var sdpLines = sdp.split('\r\n');
// Search for m line.
for (var i = 0; i < sdpLines.length; i++) {
if (sdpLines[i].search('m=audio') !== -1) {
var mLineIndex = i;
break;
}
}
if (mLineIndex === null)
return sdp;
// If Opus is available, set it as the default in m line.
for (var 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 = new Array();
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;
}
当涉及到 waitForRemoteVideo 时，该函数调用 else 条件。但是 remoteVideo 的 blob url 存在。