451

api/main.py

@@ -3,7 +3,7 @@ from pymongo import MongoClient
 from bson import ObjectId
 import hashlib
 import json
-from flask import Flask, render_template, request
+from flask import Flask, request
 from flask_socketio import SocketIO, emit, join_room, leave_room
 import time
 
@@ -46,7 +46,9 @@ def on_disconnect():
 def handle_video_frame(message):
     # 广播视频帧给老师
     global adminSid
-    socketio.emit("teacherVideo", message, room=adminSid)
+    # print(f"Received video frame from {message['userId']}")
+    socketio.emit("teacherVideo", message, to=adminSid, namespace="/ws/video")
+    #
 
 
 # md5加密

front/src/views/student.vue

@@ -185,17 +185,8 @@ export default {
       canvas.height = video.offsetHeight;
       let sendFrame = () => {
         ctx.drawImage(video, 0, 0, canvas.width, canvas.height);
-        canvas.toBlob((blob) => {
-          let reader = new FileReader();
-          reader.onloadend = () => {
-            let arrayBuffer = reader.result;
-            that.socket.emit('video', arrayBuffer,);
-          };
-          reader.readAsArrayBuffer(blob);
-          // let arrayBufferView = new Uint8Array(blob);
-          // console.log(89444, video)
-          // that.socket.emit('video', arrayBufferView.buffer);
-        }, 'image/png');
+        let dataURL = canvas.toDataURL('image/jpeg', 0.3);
+        that.socket.emit('video', { userId: this.userId, data: dataURL });
       };
       setInterval(sendFrame, 1000 / 30); // 30 FPS
     },

front/src/views/teacher.vue

@@ -20,18 +20,19 @@
     </el-col>
     <el-col :span="10">
       <el-row>
-        <el-col :span="12">
-          <video ref="videoEL1" class="canvasClass"></video>
+        <el-col :span="12" v-for="studentItem in tableData" :key="studentItem._id">
+          <!-- <img v-if="imageSrc" :src="imageSrc" class="canvasClass" alt="Video Frame" /> -->
+          <canvas :ref="`videoEL${studentItem._id}`" class="canvasClass"></canvas>
         </el-col>
-        <el-col :span="12">
-          <video ref="videoEL2" class="canvasClass"></video>
+        <!-- <el-col :span="12">
+          <canvas ref="videoEL2" class="canvasClass"></canvas>
         </el-col>
         <el-col :span="12">
-          <video ref="videoEL3" class="canvasClass"></video>
+          <canvas ref="videoEL3" class="canvasClass"></canvas>
         </el-col>
         <el-col :span="12">
-          <video ref="videoEL4" class="canvasClass"></video>
-        </el-col>
+          <canvas ref="videoEL4" class="canvasClass"></canvas>
+        </el-col> -->
       </el-row>
     </el-col>
   </el-row>
@@ -204,6 +205,8 @@ export default {
       formDisabled: false,
       socket: null,
       videoStream: null,
+      imageSrc: "",
+      canvasObj: {},
     };
   },
   watch: {},
@@ -213,6 +216,7 @@ export default {
     this.dealFormHeader()
     await this.init();
     await this.initWebSocket()
+    await this.initCanvas()
 
   },
   methods: {
@@ -243,7 +247,7 @@ export default {
       let res = await getUser({
         ...params,
       });
-      this.tableData = res.list;
+      this.tableData = _.filter(res.list, o => o.isAdmin === 0);
     },
     // 打开新增学生的模态框
     async addUserData() {
@@ -349,6 +353,15 @@ export default {
         });
       })
     },
+    // 
+    async initCanvas() {
+      for (let i = 0; i < this.tableData.length; i++) {
+        let element = this.tableData[i];
+        if (this.$refs[`videoEL${element._id}`]) {
+          this.canvasObj[`context${element._id}`] = this.$refs[`videoEL${element._id}`][0].getContext('2d');
+        }
+      }
+    },
     // 初始化实时传输信息
     async initWebSocket() {
       this.socket = io('http://localhost:5000/ws/video',
@@ -360,19 +373,14 @@ export default {
       });
       this.socket.on('teacherVideo', (data) => {
         // 在这里处理接收到的视频帧
-        
-        const arrayBuffer = event.data;
-        const blob = new Blob([arrayBuffer], { type: 'image/jpeg' });
-        const urlCreator = window.URL || window.webkitURL;
-        const imageUrl = urlCreator.createObjectURL(blob);
-        const img = new Image();
-        img.onload = function () {
-          urlCreator.revokeObjectURL(this.src);
+        let blob = this.dataURLToBlob(data.data);
+        let urlCreator = window.URL || window.webkitURL;
+        let imageUrl = urlCreator.createObjectURL(blob);
+        let image = new Image();
+        image.onload = () => {
+          this.canvasObj[`context${data.userId}`].drawImage(image, 0, 0, image.width, image.height, 0, 0, 300, 150);
         };
-        img.src = imageUrl;
-        this.$refs.videoEL1.srcObject = null; // 清空当前流
-        this.$refs.videoEL1.src = imageUrl; // 设置新图像作为视频源
-        this.$refs.videoEL1.play();
+        image.src = imageUrl;
       });
     },
     stopVideoStream() {
@@ -385,6 +393,24 @@ export default {
         this.socket.disconnect();
       }
     },
+    dataURLToBlob(dataURL) {
+      let parts = dataURL.split(';base64,');
+      let contentType = parts[0].split(':')[1];
+      let byteCharacters = atob(parts[1]);
+      let byteArrays = [];
+
+      for (let offset = 0; offset < byteCharacters.length; offset += 1024) {
+        let slice = byteCharacters.slice(offset, offset + 1024);
+        let byteNumbers = new Array(slice.length);
+        for (let i = 0; i < slice.length; i++) {
+          byteNumbers[i] = slice.charCodeAt(i);
+        }
+        let byteArray = new Uint8Array(byteNumbers);
+        byteArrays.push(byteArray);
+      }
+      let blob = new Blob(byteArrays, { type: contentType });
+      return blob;
+    },
   },
   beforeUnmount() {
     this.stopVideoStream();