使用视频帧保证切换问题

src/index.js

@@ -648,24 +648,67 @@ class WebRTCChat {
         }
     }
 
+    // 添加视频帧缓存方法
+    captureVideoFrame(videoElement) {
+        const canvas = document.createElement('canvas');
+        const ctx = canvas.getContext('2d');
+        
+        canvas.width = videoElement.videoWidth || videoElement.clientWidth;
+        canvas.height = videoElement.videoHeight || videoElement.clientHeight;
+        
+        // 绘制当前视频帧到canvas
+        ctx.drawImage(videoElement, 0, 0, canvas.width, canvas.height);
+        
+        return canvas.toDataURL('image/jpeg', 0.8);
+    }
+
+    // 创建静态帧显示元素
+    createFrameOverlay(frameData) {
+        const overlay = document.createElement('div');
+        overlay.style.position = 'absolute';
+        overlay.style.top = '0';
+        overlay.style.left = '0';
+        overlay.style.width = '100%';
+        overlay.style.height = '100%';
+        overlay.style.backgroundImage = `url(${frameData})`;
+        overlay.style.backgroundSize = 'cover';
+        overlay.style.backgroundPosition = 'center';
+        overlay.style.zIndex = '10';
+        overlay.style.pointerEvents = 'none';
+        overlay.id = 'video-frame-overlay';
+        
+        return overlay;
+    }
+
     // 新增平滑视频切换方法
     async switchVideoStreamSmooth(videoFile, type = '', text = '') {
         try {
-            this.logMessage(`开始平滑切换视频流: ${videoFile} (${type})`, 'info');
+            this.logMessage(`开始无闪烁切换视频流: ${videoFile} (${type})`, 'info');
             
-            // 检查是否已缓存，如果已缓存则不显示加载指示器
+            // 1. 捕获当前视频的最后一帧
+            const currentVideo = this.activeVideoElement === 'main' ? this.recordedVideo : this.recordedVideoBuffer;
+            const bufferVideo = this.activeVideoElement === 'main' ? this.recordedVideoBuffer : this.recordedVideo;
+            
+            let frameData = null;
+            if (currentVideo.readyState >= 2 && currentVideo.currentTime > 0) {
+                frameData = this.captureVideoFrame(currentVideo);
+            }
+            
+            // 2. 创建并显示静态帧覆盖层
+            let frameOverlay = null;
+            if (frameData) {
+                frameOverlay = this.createFrameOverlay(frameData);
+                currentVideo.parentElement.appendChild(frameOverlay);
+            }
+            
+            // 3. 检查是否已缓存
             const isCached = this.videoStreams.has(videoFile);
             if (!isCached) {
                 this.showVideoLoading();
             }
             
-            // 确定当前活跃的视频元素和缓冲元素
-            const currentVideo = this.activeVideoElement === 'main' ? this.recordedVideo : this.recordedVideoBuffer;
-            const bufferVideo = this.activeVideoElement === 'main' ? this.recordedVideoBuffer : this.recordedVideo;
-            
-            // 检查是否已缓存
+            // 4. 准备新视频流
             let newStream;
-            
             if (isCached) {
                 const cachedStream = this.videoStreams.get(videoFile);
                 if (cachedStream && cachedStream.getTracks().length > 0) {
@@ -678,36 +721,43 @@ class WebRTCChat {
                 newStream = await this.createVideoStream(videoFile);
             }
             
-            // 在缓冲视频元素中预加载新视频
+            // 5. 在缓冲视频元素中预加载新视频
             bufferVideo.srcObject = newStream;
             
-            // 等待缓冲视频准备就绪
+            // 6. 等待新视频完全准备好（至少渲染一帧）
             await new Promise((resolve, reject) => {
                 const timeout = setTimeout(() => {
                     reject(new Error('视频加载超时'));
                 }, 5000);
                 
-                const onCanPlay = () => {
+                const onReady = () => {
                     clearTimeout(timeout);
                     bufferVideo.removeEventListener('canplay', onCanPlay);
-                    bufferVideo.removeEventListener('error', onError);
-                    
-                    // 确保视频渲染了至少一帧
-                    if (bufferVideo.readyState >= 2) {
-                        resolve();
-                    } else {
-                        // 等待第一帧渲染
-                        const onTimeUpdate = () => {
                     bufferVideo.removeEventListener('timeupdate', onTimeUpdate);
+                    bufferVideo.removeEventListener('error', onError);
                     resolve();
                 };
-                        bufferVideo.addEventListener('timeupdate', onTimeUpdate, { once: true });
+                
+                const onCanPlay = () => {
+                    // 开始播放新视频
+                    bufferVideo.play().then(() => {
+                        // 等待至少一帧渲染
+                        if (bufferVideo.currentTime > 0) {
+                            onReady();
+                        }
+                    }).catch(reject);
+                };
+                
+                const onTimeUpdate = () => {
+                    if (bufferVideo.currentTime > 0) {
+                        onReady();
                     }
                 };
                 
                 const onError = (error) => {
                     clearTimeout(timeout);
                     bufferVideo.removeEventListener('canplay', onCanPlay);
+                    bufferVideo.removeEventListener('timeupdate', onTimeUpdate);
                     bufferVideo.removeEventListener('error', onError);
                     reject(error);
                 };
@@ -716,27 +766,31 @@ class WebRTCChat {
                     onCanPlay();
                 } else {
                     bufferVideo.addEventListener('canplay', onCanPlay);
+                    bufferVideo.addEventListener('timeupdate', onTimeUpdate);
                     bufferVideo.addEventListener('error', onError);
                 }
-                
-                // 开始播放缓冲视频
-                bufferVideo.play().catch(onError);
             });
             
-            // 只有显示了加载指示器才隐藏
+            // 7. 立即切换视频显示（无过渡）
+            bufferVideo.style.zIndex = '2';
+            currentVideo.style.zIndex = '1';
+            
+            // 8. 移除静态帧覆盖层
+            if (frameOverlay) {
+                frameOverlay.remove();
+            }
+            
+            // 9. 隐藏加载指示器
             if (!isCached) {
                 this.hideVideoLoading();
             }
             
-            // 执行淡入淡出切换
-            // await this.performVideoTransition(currentVideo, bufferVideo);
-            
-            // 更新当前视频流和活跃元素
+            // 10. 更新状态
             this.currentVideoStream = newStream;
             this.currentVideo = videoFile;
             this.activeVideoElement = this.activeVideoElement === 'main' ? 'buffer' : 'main';
             
-            // 停止旧视频流（延迟停止避免闪烁）
+            // 11. 延迟清理旧视频流
             setTimeout(() => {
                 if (currentVideo.srcObject && currentVideo.srcObject !== newStream) {
                     currentVideo.srcObject.getTracks().forEach(track => track.stop());
@@ -744,7 +798,7 @@ class WebRTCChat {
                 }
             }, 1000);
             
-            // 更新WebRTC连接中的视频轨道
+            // 12. 更新WebRTC连接
             if (this.peerConnection && this.videoSender) {
                 const newVideoTrack = newStream.getVideoTracks()[0];
                 if (newVideoTrack) {
@@ -752,7 +806,7 @@ class WebRTCChat {
                 }
             }
             
-            // 更新显示信息
+            // 13. 更新显示信息
             if (text) {
                 this.currentVideoName.textContent = `交互视频: ${videoFile} (${type}: ${text})`;
                 this.logMessage(`成功切换到交互视频流: ${videoFile} (${type}: ${text})`, 'success');
@@ -762,11 +816,17 @@ class WebRTCChat {
             }
             
         } catch (error) {
-            this.logMessage(`平滑切换视频流失败: ${error.message}`, 'error');
-            // 确保隐藏加载指示器
+            this.logMessage(`视频流切换失败: ${error.message}`, 'error');
+            
+            // 清理可能残留的覆盖层
+            const overlay = document.getElementById('video-frame-overlay');
+            if (overlay) {
+                overlay.remove();
+            }
+            
             this.hideVideoLoading();
             
-            // 如果切换失败，尝试回到默认视频
+            // 回退到默认视频
             if (videoFile !== this.defaultVideo) {
                 this.logMessage('尝试回到默认视频', 'info');
                 await this.switchVideoStreamSmooth(this.defaultVideo, 'fallback');
@@ -774,56 +834,7 @@ class WebRTCChat {
         }
     }
 
-    // 执行视频过渡动画
-    async performVideoTransition(currentVideo, bufferVideo) {
-        return new Promise((resolve) => {
-            // 确保初始状态正确
-            bufferVideo.style.opacity = '0';
-            bufferVideo.style.zIndex = '3';
-            currentVideo.style.opacity = '1';
-            currentVideo.style.zIndex = '2';
 
-            // 设置过渡属性（如果还没有）
-            if (!bufferVideo.style.transition) {
-                bufferVideo.style.transition = 'opacity 0.3s cubic-bezier(0.4, 0.0, 0.2, 1)';
-            }
-            if (!currentVideo.style.transition) {
-                currentVideo.style.transition = 'opacity 0.3s cubic-bezier(0.4, 0.0, 0.2, 1)';
-            }
-            
-            // 强制重绘以确保样式生效
-            bufferVideo.offsetHeight;
-            
-            // 开始过渡
-            requestAnimationFrame(() => {
-                bufferVideo.style.opacity = '1';
-                currentVideo.style.opacity = '0';
-            });
-            
-            // 监听过渡完成
-            const onTransitionEnd = (e) => {
-                if (e.target === bufferVideo && e.propertyName === 'opacity') {
-                    bufferVideo.removeEventListener('transitionend', onTransitionEnd);
-                    
-                    // 重置z-index
-                    currentVideo.style.zIndex = '1';
-                    bufferVideo.style.zIndex = '2';
-                    
-                    resolve();
-                }
-            };
-            
-            bufferVideo.addEventListener('transitionend', onTransitionEnd);
-            
-            // 备用超时机制
-            setTimeout(() => {
-                bufferVideo.removeEventListener('transitionend', onTransitionEnd);
-                currentVideo.style.zIndex = '1';
-                bufferVideo.style.zIndex = '2';
-                resolve();
-            }, 400);
-        });
-    }
 
     // 显示加载指示器
     showVideoLoading() {