v11: Fix DVR snap-back — override hls.startLoad

Gốc rễ: HLS.js startLoad(-1) tự động seek về live edge mỗi khi load segment → user seek back bị snap về LIVE liên tục.

Giải pháp: Override hls.startLoad method:
- Lần đầu load: startLoad(-1) bình thường → stream phát từ live edge
- Sau khi user seek back (_dvrHasUserSeeked=true): startLoad(cur-5) thay vì startLoad(-1) → load segment từ vị trí hiện tại, KHÔNG seek về live
- Nút LIVE: reset _dvrHasUserSeeked=false → lần sau startLoad(-1) hoạt động bình thường
- timeupdate: tự động clear _dvrHasUserSeeked khi playhead chạm live edge

→ Không cần intercept seeked (tránh loop), không cần liveSyncDurationCount nhỏ (tránh snap). Chặn ngay từ gốc.

static/yt_live.js

@@ -1,6 +1,6 @@
-// === VNEWS — VTV LIVE + Inline Recorder v10 ===
+// === VNEWS — VTV LIVE + Inline Recorder v11 ===
 // Features: DVR 5-min rewind buffer (seek & stay), PiP, mini-player, INLINE RECORDER with ratio crop + AI title + Short AI upload
-// v10: Fix DVR — keep liveSync for stream start, but intercept HLS auto-snap via seeking/seeked events to preserve user position
+// v11: Fix DVR snap-back — override hls.startLoad to block auto-live-snap. Only seek to live on initial load or LIVE btn click
 
 (function(){
   if(window._ytLiveLoaded) return;
@@ -23,6 +23,8 @@
   let _dvrSeekBarTimer = null;
   let _dvrUserSeeking = false;      // true while user is dragging DVR seek handle
   let _dvrLastSeenEdge = false;    // track if playhead was at live edge before seek
+  let _dvrHasUserSeeked = false;   // true once user manually seeks back from live
+  let _dvrStartLoadOrig = null;    // original hls.startLoad reference
 
   // ===== RECORDER STATE =====
   const _rec = {
@@ -684,12 +686,14 @@
       const bufferStart = Math.max(0, duration - DVR_BUFFER_SECONDS);
       const seekTime = bufferStart + pct * (duration - bufferStart);
       _dvrUserSeeking = !isRelease;
+      // v11: Mark as user-seeked if not at live edge
+      if (duration - seekTime > 5) {
+        _dvrHasUserSeeked = true;
+      }
       video.currentTime = seekTime;
       if (isRelease) {
-        // Resume playback after seek release
         video.play().catch(()=>{});
       } else {
-        // Pause while dragging for smooth scrubbing
         video.pause();
       }
       updateDVRUI();
@@ -711,6 +715,7 @@
       const video = document.getElementById('vtv-player');
       if (video && _hls) {
         _dvrUserSeeking = false;
+        _dvrHasUserSeeked = false; // reset — allow auto-live again
         video.currentTime = video.duration;
         video.play().catch(()=>{});
         updateDVRUI();
@@ -721,13 +726,17 @@
     if (_dvrSeekBarTimer) clearInterval(_dvrSeekBarTimer);
     _dvrSeekBarTimer = setInterval(updateDVRUI, 1000);
 
-    // v10: Track whether playhead is at live edge (for seeked event guard)
+    // v11: Track live edge state; auto-clear _dvrHasUserSeeked when buffer catches up
     video.addEventListener('timeupdate', function() {
       if (!_hls) return;
       const dur = video.duration;
       if (!dur || !isFinite(dur)) return;
       const behind = dur - video.currentTime;
       _dvrLastSeenEdge = (behind < 2);
+      // If playhead reached live edge naturally, allow auto-live again
+      if (behind < 1 && _dvrHasUserSeeked) {
+        _dvrHasUserSeeked = false;
+      }
     });
   }
 
@@ -844,46 +853,60 @@
     if(idx>=urls.length){loadEl.style.display='none';errEl.style.display='flex';errMsg.textContent=name+': Tất cả nguồn lỗi.';return;}
     const src=urls[idx]; loadEl.innerHTML='<div class="vtv-spinner"></div>Kết nối '+name+' ('+(idx+1)+'/'+urls.length+')...';
     if(typeof Hls!=='undefined'&&Hls.isSupported()){
-      // v10: DVR 5min — keep liveSync for edge tracking, but override seek snap-back
+      // v11: DVR 5min — override hls.startLoad to prevent auto-live-snap
       const hls=new Hls({
         enableWorker:true,lowLatencyMode:false,startLevel:0,capLevelToPlayerSize:true,
         maxBufferLength:120,maxMaxBufferLength:180,
         liveBackBufferLength:DVR_BUFFER_SECONDS,
-        liveSyncDurationCount:3,liveMaxLatencyDurationCount:6,
+        liveSyncDurationCount:999999,liveMaxLatencyDurationCount:999999,
         fragLoadingTimeOut:10000,manifestLoadingTimeOut:10000
       });
       _hls=hls; hls.loadSource(src); hls.attachMedia(video);
-      // v10: After manifest loaded, seek to live edge first, then play
+
+      // v11: Override startLoad — only seek to live on initial load, never auto-snap back
+      _dvrStartLoadOrig = hls.startLoad.bind(hls);
+      hls.startLoad = function(position) {
+        // First call (initial load): seek to live edge
+        if (!_dvrHasUserSeeked && position === -1) {
+          _dvrStartLoadOrig(position);
+          return;
+        }
+        // After user sought back: load segments but DON'T seek to live edge
+        // Pass a large negative value to load from buffer start instead
+        if (_dvrHasUserSeeked && position === -1) {
+          // Load from current buffer position, not live edge
+          const dur = video.duration;
+          const cur = video.currentTime;
+          if (dur && isFinite(dur) && cur && isFinite(cur)) {
+            // Load from slightly behind current position to ensure smooth playback
+            _dvrStartLoadOrig(cur - 5);
+          } else {
+            _dvrStartLoadOrig(position);
+          }
+          return;
+        }
+        _dvrStartLoadOrig(position);
+      };
+
+      // v11: After manifest loaded, seek to live edge first, then play
       hls.on(Hls.Events.MANIFEST_PARSED,(ev,data)=>{
         loadEl.style.display='none';video.style.display='block';
-        // Start at live edge so stream plays immediately
         const dur = video.duration;
         if(dur && isFinite(dur)){ video.currentTime = dur; }
         video.play().catch(()=>{});
       });
-      // (live-snap interception handled via video seeking/seeked events below)
-      // v10: Block HLS auto-live-snap — restore user position when HLS fights back
-      let _preSeekTime = 0;
-      let _dvrRestoreLock = false; // prevent restore loop
-      video.addEventListener('seeking',function(){
-        if(_dvrRestoreLock) return;
-        _preSeekTime = video.currentTime;
-      });
-      video.addEventListener('seeked',function(){
-        if(_dvrUserSeeking || _dvrRestoreLock) return;
+
+      // v11: Track when user manually seeks back from live
+      video.addEventListener('seeking', function() {
+        if (_dvrUserSeeking) return;
         const dur = video.duration;
-        if(!dur || !isFinite(dur)) return;
+        if (!dur || !isFinite(dur)) return;
         const behind = dur - video.currentTime;
-        // If HLS.js snapped to live (behind < 0.5s) but user was >3s behind, restore
-        if(behind < 0.5 && _preSeekTime > 0){
-          const userBehind = dur - _preSeekTime;
-          if(userBehind > 3){
-            _dvrRestoreLock = true;
-            video.currentTime = _preSeekTime;
-            setTimeout(()=>{ _dvrRestoreLock = false; },500);
-          }
+        if (behind > 5) {
+          _dvrHasUserSeeked = true;
         }
       });
+
       let rec=0; hls.on(Hls.Events.ERROR,(ev,data)=>{if(data.fatal){if(data.type===Hls.ErrorTypes.NETWORK_ERROR){rec++;if(rec<=3)setTimeout(()=>hls.startLoad(),2000);else{hls.destroy();_hls=null;_tryPlay(video,urls,idx+1,name,loadEl,errEl,errMsg);}}else if(data.type===Hls.ErrorTypes.MEDIA_ERROR){try{hls.recoverMediaError();}catch(e){}}else{hls.destroy();_hls=null;_tryPlay(video,urls,idx+1,name,loadEl,errEl,errMsg);}}});
     }else if(video.canPlayType('application/vnd.apple.mpegurl')){
       video.src=src;