webrtc笔记(5): 基于kurento media server的多人视频聊天示例

忘是亡心i 2021-11-17 12:36 363阅读 0赞

这是[kurento tutorial中的一个例子][kurento tutorial](groupCall)，用于多人音视频通话，效果如下：

登录界面：

![27612-20190714195504363-986228458.png][]

聊天界面：

![27612-20190714195421231-494894219.png][]

运行方法：

1、本地用docker把kurento server跑起来

2、idea里启用这个项目

3、浏览器里输入https://localhost:8443/ 输入用户名、房间号，然后再开一个浏览器tab页，输入一个不同的用户名，房间号与第1个tab相同，正常情况下，这2个tab页就能聊上了，还可以再加更多tab模拟多人视频(注：docker容器性能有限，mac本上实测，越过4个人，就很不稳定了）

下面是该项目的一些代码和逻辑分析：

一、主要模型的类图如下：

![点击查看原图][27612-20190714203514291-299143894.png]

UserSession类：代表每个连接进来的用户会话信息。

Room类：即房间，1个房间可能有多个UserSession实例。

RoomManager类：房间管理，用于创建或销毁房间。

UserRegistry类：用户注册类，即管理用户。

二、主要代码逻辑：

1、创建房间入口

public Room getRoom(String roomName) {
        log.debug("Searching for room {}", roomName);
        Room room = rooms.get(roomName);
    
        if (room == null) {
          log.debug("Room {} not existent. Will create now!", roomName);
          room = new Room(roomName, kurento.createMediaPipeline());
          rooms.put(roomName, room);
        }
        log.debug("Room {} found!", roomName);
        return room;
      }

注：第7行，每个房间实例创建时，都绑定了一个对应的MediaPipeline（用于隔离不同房间的媒体信息等）

2、创建用户实例入口

public UserSession(final String name, String roomName, final WebSocketSession session,
                           MediaPipeline pipeline) {
    
            this.pipeline = pipeline;
            this.name = name;
            this.session = session;
            this.roomName = roomName;
            this.outgoingMedia = new WebRtcEndpoint.Builder(pipeline).build();
    
            this.outgoingMedia.addIceCandidateFoundListener(event -> {
                JsonObject response = new JsonObject();
                response.addProperty("id", "iceCandidate");
                response.addProperty("name", name);
                response.add("candidate", JsonUtils.toJsonObject(event.getCandidate()));
                try {
                    synchronized (session) {
                        session.sendMessage(new TextMessage(response.toString()));
                    }
                } catch (IOException e) {
                    log.debug(e.getMessage());
                }
            });
        }

UserSession的构造函数上，把房间实例的pipeline做为入参传进来，然后上行传输的WebRtcEndPoint实例outgoingMedia又跟pipeline绑定(第8行)。这样："用户实例--pipeline实例--房间实例" 就串起来了。

用户加入房间的代码：

public UserSession join(String userName, WebSocketSession session) throws IOException {
            log.info("ROOM {}: adding participant {}", this.name, userName);
            final UserSession participant = new UserSession(userName, this.name, session, this.pipeline);
    
            //示例工程上，没考虑“相同用户名”的人进入同1个房间的情况，这里加上了“用户名重名”检测
            if (participants.containsKey(userName)) {
                final JsonObject jsonFailMsg = new JsonObject();
                final JsonArray jsonFailArray = new JsonArray();
                jsonFailArray.add(userName + " exist!");
                jsonFailMsg.addProperty("id", "joinFail");
                jsonFailMsg.add("data", jsonFailArray);
                participant.sendMessage(jsonFailMsg);
                participant.close();
                return null;
            }
    
            joinRoom(participant);
            participants.put(participant.getName(), participant);
            sendParticipantNames(participant);
            return participant;
        }

原代码没考虑到用户名重名的问题，我加上了这段检测，倒数第2行代码，sendParticipantNames在加入成功后，给房间里的其它人发通知。

3、SDP交换的入口

kurento-group-call/src/main/resources/static/js/conferenceroom.js 中有一段监听websocket的代码：

ws.onmessage = function (message) {
        let parsedMessage = JSON.parse(message.data);
        console.info('Received message: ' + message.data);
    
        switch (parsedMessage.id) {
            case 'existingParticipants':
                onExistingParticipants(parsedMessage);
                break;
            case 'newParticipantArrived':
                onNewParticipant(parsedMessage);
                break;
            case 'participantLeft':
                onParticipantLeft(parsedMessage);
                break;
            case 'receiveVideoAnswer':
                receiveVideoResponse(parsedMessage);
                break;
            case 'iceCandidate':
                participants[parsedMessage.name].rtcPeer.addIceCandidate(parsedMessage.candidate, function (error) {
                    if (error) {
                        console.error("Error adding candidate: " + error);
                        return;
                    }
                });
                break;
            case 'joinFail':
                alert(parsedMessage.data[0]);
                window.location.reload();
                break;
            default:
                console.error('Unrecognized message', parsedMessage);
        }
    }

服务端在刚才提到的sendParticipantNames后，会给js发送各种消息，existingParticipants(其它人加入)、newParticipantArrived(新人加入) 这二类消息，就会触发generateOffer，开始向服务端发送SDP

4、服务端回应各种websocket消息

org.kurento.tutorial.groupcall.CallHandler\#handleTextMessage 信令处理的主要逻辑，就在这里：

@Override
        public void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
            final JsonObject jsonMessage = gson.fromJson(message.getPayload(), JsonObject.class);
    
            final UserSession user = registry.getBySession(session);
    
            if (user != null) {
                log.debug("Incoming message from user '{}': {}", user.getName(), jsonMessage);
            } else {
                log.debug("Incoming message from new user: {}", jsonMessage);
            }
    
            switch (jsonMessage.get("id").getAsString()) {
                case "joinRoom":
                    joinRoom(jsonMessage, session);
                    break;
                case "receiveVideoFrom":
                    final String senderName = jsonMessage.get("sender").getAsString();
                    final UserSession sender = registry.getByName(senderName);
                    final String sdpOffer = jsonMessage.get("sdpOffer").getAsString();
                    user.receiveVideoFrom(sender, sdpOffer);
                    break;
                case "leaveRoom":
                    leaveRoom(user);
                    break;
                case "onIceCandidate":
                    JsonObject candidate = jsonMessage.get("candidate").getAsJsonObject();
    
                    if (user != null) {
                        IceCandidate cand = new IceCandidate(candidate.get("candidate").getAsString(),
                                candidate.get("sdpMid").getAsString(), candidate.get("sdpMLineIndex").getAsInt());
                        user.addCandidate(cand, jsonMessage.get("name").getAsString());
                    }
                    break;
                default:
                    break;
            }
        }

其中user.receiveVideoFrom方法，就会回应SDP

public void receiveVideoFrom(UserSession sender, String sdpOffer) throws IOException {
            log.info("USER {}: connecting with {} in room {}", this.name, sender.getName(), this.roomName);
    
            log.trace("USER {}: SdpOffer for {} is {}", this.name, sender.getName(), sdpOffer);
    
            final String ipSdpAnswer = this.getEndpointForUser(sender).processOffer(sdpOffer);
            final JsonObject scParams = new JsonObject();
            scParams.addProperty("id", "receiveVideoAnswer");
            scParams.addProperty("name", sender.getName());
            scParams.addProperty("sdpAnswer", ipSdpAnswer);
    
            log.trace("USER {}: SdpAnswer for {} is {}", this.name, sender.getName(), ipSdpAnswer);
            this.sendMessage(scParams);
            log.debug("gather candidates");
            this.getEndpointForUser(sender).gatherCandidates();
        }

SDP和ICE信息交换完成，就开始视频通讯了。

参考文章：

[https://doc-kurento.readthedocs.io/en/6.10.0/tutorials/java/tutorial-groupcall.html][https_doc-kurento.readthedocs.io_en_6.10.0_tutorials_java_tutorial-groupcall.html]

转载于:https://www.cnblogs.com/yjmyzz/p/webrtc-groupcall-using-kurento.html

[kurento tutorial]: https://github.com/Kurento/kurento-tutorial-java/tree/6.10.0/kurento-group-call
[27612-20190714195504363-986228458.png]: /images/20211116/bbd0b8dc594e44b7affa099860216af2.png
[27612-20190714195421231-494894219.png]: /images/20211116/658ed760458345ddbb1ed46c7f371e92.png
[27612-20190714203514291-299143894.png]: /images/20211116/8f37cb0e896d46d8b5518515b0c848a5.png
[https_doc-kurento.readthedocs.io_en_6.10.0_tutorials_java_tutorial-groupcall.html]: https://doc-kurento.readthedocs.io/en/6.10.0/tutorials/java/tutorial-groupcall.html