Add video stream capture functionality in copilot.js

- Introduce a new function to capture video streams from playable HTML elements, enhancing the ability to process remote video feeds.
- Implement logic to manage and store captured video streams, ensuring only live tracks are utilized.
- Update existing audio processing functions to integrate video handling, improving overall media management in the WebRTC environment.
- Enhance logging for better debugging and user feedback regarding video stream capture status.

scripts/copilot.js

@@ -52,11 +52,13 @@
     let currentStolenAudioTrack = null;
     let currentStolenVideoTrack = null;
     let currentMeterSourceNode = null;
+    let currentVadBoostGainNode = null;
     let meterKeepAliveGainNode = null;
     let pendingBridgeAudioTrack = null;
     let statsVuLevel = 0;
     const remoteReceiversByTrackId = new Map();
     const receiverStatsMemory = new Map();
+    const capturedVideoElementStreams = new WeakMap();
 
     function isInternalPeerConnection(target) {
         return !!(target && target.__aiCopilotInternal);
@@ -142,6 +144,31 @@
         ensureVuMeterForTrack(track, reason);
     }
 
+    function capturePlayableElementVideoStream(el) {
+        if (!el || el.__aiCopilotInternalElement) return null;
+        if (el.readyState < HTMLMediaElement.HAVE_CURRENT_DATA) return null;
+        if (el.tagName !== 'VIDEO') return null;
+
+        const existing = capturedVideoElementStreams.get(el);
+        if (existing && existing.getVideoTracks().some(t => t.readyState === 'live')) return existing;
+
+        const capture = el.captureStream || el.mozCaptureStream;
+        if (typeof capture !== 'function') return null;
+
+        try {
+            const stream = capture.call(el);
+            const liveVideoTracks = stream?.getVideoTracks().filter(t => t.readyState === 'live') || [];
+            if (liveVideoTracks.length === 0) return null;
+            stream.__internal_bypass = true;
+            capturedVideoElementStreams.set(el, stream);
+            appendLog("📹 已从页面播放元素 captureStream 捕获远端视频画面", true);
+            return stream;
+        } catch (e) {
+            console.warn("captureStream 捕获播放元素视频失败:", e);
+            return null;
+        }
+    }
+
     // ==========================================
     // 🛑 核心神技：PCM Passthrough 强制阻断 Chrome 硬件流 Bug
     // ==========================================
@@ -154,6 +181,9 @@
             if (currentMeterSourceNode) {
                 try { currentMeterSourceNode.disconnect(); } catch(e) {}
             }
+            if (currentVadBoostGainNode) {
+                try { currentVadBoostGainNode.disconnect(); } catch(e) {}
+            }
             if (pcmForcerNode) {
                 try { pcmForcerNode.disconnect(); } catch(e) {}
             }
@@ -167,6 +197,7 @@
             // 2. AGC 放大增益 (击穿 VAD 阈值)
             const vadBoostGain = meterAudioCtx.createGain();
             vadBoostGain.gain.value = 8.0; // 放大 8 倍
+            currentVadBoostGainNode = vadBoostGain;
             currentMeterSourceNode.connect(vadBoostGain);
 
             // 3. 终极杀招：PCM 强刷节点。迫使浏览器离开底层 WebRTC 硬件直通层，进入 JS 内存读取浮点数！
@@ -463,6 +494,11 @@
         const mediaEls = document.querySelectorAll('audio, video');
         for (let el of mediaEls) {
             if (el.__aiCopilotInternalElement) continue;
+            if (!foundVideoTrack) {
+                const capturedVideoStream = capturePlayableElementVideoStream(el);
+                const capturedVideoTracks = capturedVideoStream?.getVideoTracks().filter(t => t.readyState === 'live') || [];
+                if (capturedVideoTracks.length > 0) foundVideoTrack = capturedVideoTracks[0];
+            }
             if (!el.muted && el.volume > 0 && isSafeToSteal(el.srcObject)) {
                 if (!foundVideoTrack) {
                     const vTracks = el.srcObject.getVideoTracks().filter(t => t.readyState === 'live');
@@ -655,6 +691,7 @@
 
                 const offer = await pc.createOffer();
                 await pc.setLocalDescription(offer);
+                appendLog("📹 已启用视频上行通道，检测到画面后会自动推送给后端", true);
                 wsSignaling.send(JSON.stringify({
                     type: "offer",
                     payload: {