v8: DVR 5-min rewind buffer + default channel VTV6

- Đổi DEFAULT_CHANNEL từ vtv3 → vtv6
- Thêm liveBackBufferLength=300s (5 phút DVR)
- Thêm thanh seek DVR để tua lại trước đó tối đa 5 phút
- Nút LIVE để quay về realtime
- Cập nhật hint recorder: tua DVR về trước 5′ r�i record

static/yt_live.js

@@ -1,6 +1,6 @@
-// === VNEWS — VTV LIVE + Inline Recorder v7 ===
-// Features: PiP, mini-player, INLINE RECORDER with ratio crop + AI title + Short AI upload
-// FIX v7: uploadToWall robust JSON parse, processRatio timeout fallback, no premature revoke
+// === VNEWS — VTV LIVE + Inline Recorder v8 ===
+// Features: DVR 5-min rewind buffer, PiP, mini-player, INLINE RECORDER with ratio crop + AI title + Short AI upload
+// v8: Add liveBackBufferLength=300s (5min DVR), seek bar for rewind, DEFAULT_CHANNEL=vtv6
 
 (function(){
   if(window._ytLiveLoaded) return;
@@ -14,11 +14,13 @@
     {id:'vtv9',name:'VTV9',badge:'Miền Bắc'},{id:'vtv10',name:'VTV10',badge:'Cần Thơ'},
     {id:'vtvprime',name:'VTVPrime',badge:'Prime'},
   ];
-  const DEFAULT_CHANNEL = 'vtv3';
+  const DEFAULT_CHANNEL = 'vtv6';
+  const DVR_BUFFER_SECONDS = 300; // 5 minutes DVR buffer
   const NEEDS_PROXY = /fptplay\.net/;
   const STREAMS = {};
   let _currentCh = null, _hls = null, _loading = false, _blockInserted = false;
   let _streamsLoaded = false, _pipActive = false, _miniActive = false, _vtvPinned = false;
+  let _dvrSeekBarTimer = null;
 
   // ===== RECORDER STATE =====
   const _rec = {
@@ -48,6 +50,18 @@
   .vtv-load{display:flex;align-items:center;justify-content:center;height:180px;color:#00ccff;font-size:12px;flex-direction:column;gap:8px}
   .vtv-spinner{width:24px;height:24px;border:2px solid #333;border-top-color:#00ccff;border-radius:50%;animation:vtvspin .8s linear infinite}
   @keyframes vtvspin{to{transform:rotate(360deg)}}
+  /* DVR Seek Bar */
+  .vtv-dvr-bar{display:none;align-items:center;gap:6px;padding:4px 8px 6px;background:#0a0f1a;border-top:1px solid #1a2a3a}
+  .vtv-dvr-bar.visible{display:flex}
+  .vtv-dvr-label{font-size:9px;color:#00ccff;font-weight:700;white-space:nowrap}
+  .vtv-dvr-track{flex:1;position:relative;height:20px;background:#0d1a2a;border-radius:4px;overflow:hidden;cursor:pointer;border:1px solid #1a3a5a}
+  .vtv-dvr-buffer{position:absolute;top:0;bottom:0;left:0;background:rgba(0,102,204,0.15);border-right:2px solid #0066cc}
+  .vtv-dvr-live-dot{position:absolute;top:50%;transform:translate(-50%,-50%);width:8px;height:8px;border-radius:50%;background:#e74c3c;box-shadow:0 0 6px #e74c3c;z-index:3}
+  .vtv-dvr-handle{position:absolute;top:50%;transform:translate(-50%,-50%);width:12px;height:12px;border-radius:50%;background:#00ccff;border:2px solid #fff;box-shadow:0 0 4px rgba(0,204,255,0.5);z-index;cursor:grab}
+  .vtv-dvr-handle:active{cursor:grabbing}
+  .vtv-dvr-time{font-size:9px;color:#8ab4d8;white-space:nowrap;min-width:38px;text-align:right}
+  .vtv-dvr-live-btn{background:#1a0808;border:1px solid #660000;color:#ff6666;font-size:9px;padding:2px 6px;border-radius:4px;cursor:pointer;font-weight:700;white-space:nowrap}
+  .vtv-dvr-live-btn:hover{background:#330000;color:#ff4444}
   .vtv-controls{display:flex;align-items:center;gap:4px;padding:4px 8px;background:#0d1a2a;border-top:1px solid #1a2a3a}
   .vtv-pip-btn{background:#1a2a3a;border:1px solid #2a3a4a;color:#8ab4d8;font-size:9px;padding:3px 8px;border-radius:6px;cursor:pointer;transition:all .2s;display:flex;align-items:center;gap:4px}
   .vtv-pip-btn:hover{background:#0b4a7a;color:#fff}
@@ -75,6 +89,7 @@
   .vtv-wrap.vtv-sticky{position:sticky;top:0;z-index:48;transition:all .25s ease;box-shadow:0 4px 24px rgba(0,102,204,.35)}
   .vtv-wrap.vtv-sticky .vtv-epg{display:none}
   .vtv-wrap.vtv-sticky .vtv-controls{display:none}
+  .vtv-wrap.vtv-sticky .vtv-dvr-bar{display:none!important}
   .vtv-wrap.vtv-sticky .vtv-tabs{padding:3px 8px}
   .vtv-wrap.vtv-sticky .vtv-tab{padding:3px 7px;font-size:8px}
   .vtv-wrap.vtv-sticky .vtv-frame{max-height:140px;min-height:100px}
@@ -171,7 +186,7 @@
     if (el) el.style.display = 'none';
   }
 
-  // ===== UPLOAD TO WALL (Short AI) — v7: robust JSON parse =====
+  // ===== UPLOAD TO WALL (Short AI) =====
   function uploadToWall(blob, title, source) {
     const formData = new FormData();
     formData.append('video', blob, `vtv-${_currentCh}-${Date.now()}.webm`);
@@ -248,7 +263,7 @@
     recBtn.id = 'vtv-rec-btn';
     recBtn.className = 'vtv-rec-btn';
     recBtn.innerHTML = '<svg viewBox="0 0 24 24"><circle cx="12" cy="12" r="8"/></svg> Record';
-    recBtn.title = 'Record video ngắn từ LIVE (max 60s)';
+    recBtn.title = 'Record video ngắn từ LIVE (max 60s). Dùng DVR để tua lại trước đó tối đa 5 phút.';
     recBtn.onclick = toggleRecPanel;
     controls.appendChild(recBtn);
 
@@ -272,7 +287,7 @@
         <button class="rec-go" id="vtv-rec-go" onclick="window._vtvRecGo()" disabled>⏺ Record!</button>
         <button class="rec-reset" onclick="window._vtvRecReset()">↺ Reset</button>
       </div>
-      <div class="rec-hint" id="vtv-rec-hint">Chọn điểm bắt đầu → kết thúc (tối đa 60s)</div>
+      <div class="rec-hint" id="vtv-rec-hint">💡 Tua DVR về trước tối đa 5′ rồi chọn điểm bắt đầu → kết thúc (max 60s)</div>
       <div class="rec-status" id="vtv-rec-status">Sẵn sàng</div>
     `;
     controls.parentNode.insertBefore(inlineRec, controls.nextSibling);
@@ -435,7 +450,6 @@
     document.querySelectorAll('#vtv-rec-panel .rec-ratio-row button').forEach(b => b.classList.toggle('active', b.dataset.ratio === ratio));
   };
 
-  // ===== RECORD — captureStream with audio (unmute during record) =====
   window._vtvRecGo = function() {
     if (_rec.startTime === null || _rec.endTime === null) return;
     if (_rec.isRecording) {
@@ -518,16 +532,13 @@
     }, dur + 500);
   };
 
-  // ===== AI TITLE =====
   window._vtvRecGenAITitle = async function() {
     if (!_rec.blob) { recStatus('⚠️ Chưa record!', 'err'); return; }
     const btn = document.getElementById('vtv-rec-ai-btn');
     const input = document.getElementById('vtv-rec-title-input');
     if (!btn || !input) return;
-
     btn.disabled = true;
     btn.textContent = '⏳ Đang tạo...';
-
     try {
       const ch = CHANNELS.find(c => c.id === _currentCh);
       const channelName = ch ? ch.name : (_currentCh || 'VTV');
@@ -542,7 +553,6 @@
     }
   };
 
-  // ===== DOWNLOAD =====
   window._vtvRecDownload = function() {
     if (!_rec.blob) return;
     const title = document.getElementById('vtv-rec-title-input')?.value || '';
@@ -553,7 +563,6 @@
     }
   };
 
-  // ===== SHARE TO SHORT AI =====
   window._vtvRecShare = function() {
     if (!_rec.blob) return;
     const title = document.getElementById('vtv-rec-title-input')?.value || '';
@@ -564,10 +573,8 @@
     }
   };
 
-  // ===== RATIO CROP — v7: reliable render with timeout fallback =====
   function processRatio(blob, ratio, action, title) {
     showProc(`🔄 Đang xử lý ${ratio}...`);
-
     const blobUrl = URL.createObjectURL(blob);
     const video = document.createElement('video');
     video.src = blobUrl;
@@ -578,136 +585,35 @@
     function onReady() {
       video.removeEventListener('loadedmetadata', onReady);
       video.removeEventListener('canplay', onReady);
-
       const vw = video.videoWidth, vh = video.videoHeight;
-      if (!vw || !vh) {
-        hideProc(); recStatus('❌ Video không có kích thước hợp lệ.', 'err');
-        URL.revokeObjectURL(blobUrl); return;
-      }
-
+      if (!vw || !vh) { hideProc(); recStatus('❌ Video không có kích thước hợp lệ.', 'err'); URL.revokeObjectURL(blobUrl); return; }
       let cw, ch, sx, sy;
-      if (ratio === '1:1') {
-        const size = Math.min(vw, vh); cw = ch = size;
-        sx = Math.floor((vw - size) / 2); sy = Math.floor((vh - size) / 2);
-      } else if (ratio === '9:16') {
-        ch = vh; cw = Math.min(vw, Math.round(vh * 9 / 16));
-        sx = Math.floor((vw - cw) / 2); sy = 0;
-      } else { cw = vw; ch = vh; sx = sy = 0; }
-
+      if (ratio === '1:1') { const size = Math.min(vw, vh); cw = ch = size; sx = Math.floor((vw - size) / 2); sy = Math.floor((vh - size) / 2); }
+      else if (ratio === '9:16') { ch = vh; cw = Math.min(vw, Math.round(vh * 9 / 16)); sx = Math.floor((vw - cw) / 2); sy = 0; }
+      else { cw = vw; ch = vh; sx = sy = 0; }
       showProc(`🔄 Render ${cw}x${ch}...`);
-
-      const canvas = document.createElement('canvas');
-      canvas.width = cw; canvas.height = ch;
+      const canvas = document.createElement('canvas'); canvas.width = cw; canvas.height = ch;
       const ctx = canvas.getContext('2d');
       const canvasStream = canvas.captureStream(30);
-
       let recordStream = canvasStream;
       const audioVideo = document.createElement('video');
-      audioVideo.src = blobUrl;
-      audioVideo.muted = true;
-      audioVideo.volume = 0;
-      audioVideo.preload = 'auto';
-      audioVideo.playsInline = true;
-
-      audioVideo.onloadedmetadata = function() {
-        try {
-          const aStr = audioVideo.captureStream ? audioVideo.captureStream() : null;
-          if (aStr) {
-            const tracks = aStr.getAudioTracks();
-            if (tracks.length > 0) {
-              recordStream = new MediaStream([...canvasStream.getVideoTracks(), ...tracks]);
-              console.log('[VTV Crop] Audio merged:', tracks.length, 'tracks');
-            }
-          }
-        } catch(e) { console.warn('[VTV Crop] Audio merge failed:', e); }
-      };
-
-      const mime = MediaRecorder.isTypeSupported('video/webm;codecs=vp9,opus')
-        ? 'video/webm;codecs=vp9,opus'
-        : MediaRecorder.isTypeSupported('video/webm;codecs=vp8,opus')
-          ? 'video/webm;codecs=vp8,opus' : 'video/webm';
-
-      let rec;
-      try { rec = new MediaRecorder(recordStream, {mimeType: mime}); }
-      catch(e) { hideProc(); recStatus('❌ Lỗi MediaRecorder: ' + e.message, 'err'); URL.revokeObjectURL(blobUrl); return; }
-
+      audioVideo.src = blobUrl; audioVideo.muted = true; audioVideo.volume = 0; audioVideo.preload = 'auto'; audioVideo.playsInline = true;
+      audioVideo.onloadedmetadata = function() { try { const aStr = audioVideo.captureStream ? audioVideo.captureStream() : null; if (aStr) { const tracks = aStr.getAudioTracks(); if (tracks.length > 0) { recordStream = new MediaStream([...canvasStream.getVideoTracks(), ...tracks]); } } } catch(e) {} };
+      const mime = MediaRecorder.isTypeSupported('video/webm;codecs=vp9,opus') ? 'video/webm;codecs=vp9,opus' : MediaRecorder.isTypeSupported('video/webm;codecs=vp8,opus') ? 'video/webm;codecs=vp8,opus' : 'video/webm';
+      let rec; try { rec = new MediaRecorder(recordStream, {mimeType: mime}); } catch(e) { hideProc(); recStatus('❌ Lỗi MediaRecorder: ' + e.message, 'err'); URL.revokeObjectURL(blobUrl); return; }
       const chunks = [];
       rec.ondataavailable = e => { if(e.data && e.data.size > 0) chunks.push(e.data); };
-      rec.onstop = () => {
-        hideProc();
-        URL.revokeObjectURL(blobUrl);
-        if (chunks.length === 0) {
-          recStatus('❌ Render thất bại (không có data). Thử lại hoặc chọn "Gốc".', 'err');
-          return;
-        }
-        const out = new Blob(chunks, {type: 'video/webm'});
-        if (action === 'download') {
-          downloadBlob(out, `vtv-${_currentCh}-${ratio.replace(':','x')}-${Date.now()}.webm`);
-        } else {
-          uploadToWall(out, title);
-        }
-      };
+      rec.onstop = () => { hideProc(); URL.revokeObjectURL(blobUrl); if (chunks.length === 0) { recStatus('❌ Render thất bại.', 'err'); return; } const out = new Blob(chunks, {type: 'video/webm'}); if (action === 'download') downloadBlob(out, `vtv-${_currentCh}-${ratio.replace(':','x')}-${Date.now()}.webm`); else uploadToWall(out, title); };
       rec.onerror = e => { hideProc(); recStatus('❌ Lỗi render: ' + (e.error?.message || '?'), 'err'); URL.revokeObjectURL(blobUrl); };
-
       rec.start(200);
-
       audioVideo.play().catch(() => {});
-
-      video.play().then(() => {
-        let finished = false;
-        function finish() {
-          if (finished) return;
-          finished = true;
-          console.log('[VTV Crop] finish() called');
-          try { rec.requestData(); } catch(e) {}
-          setTimeout(() => {
-            if (rec.state !== 'inactive') rec.stop();
-            try { audioVideo.pause(); } catch(e) {}
-          }, 300);
-        }
-        video.onended = finish;
-        audioVideo.onended = finish;
-
-        const expectedDur = (video.duration || 0) * 1000;
-        if (expectedDur > 0 && isFinite(expectedDur)) {
-          setTimeout(() => {
-            if (!finished) {
-              console.warn('[VTV Crop] Timeout fallback after', expectedDur + 3000, 'ms');
-              finish();
-            }
-          }, expectedDur + 3000);
-        } else {
-          console.warn('[VTV Crop] Duration unknown, using 60s timeout');
-          setTimeout(() => {
-            if (!finished) {
-              console.warn('[VTV Crop] 60s timeout fallback');
-              finish();
-            }
-          }, 60000);
-        }
-
-        function draw() {
-          if (video.paused || video.ended) return;
-          ctx.drawImage(video, sx, sy, cw, ch, 0, 0, cw, ch);
-          requestAnimationFrame(draw);
-        }
-        draw();
-      }).catch(e => {
-        hideProc(); recStatus('❌ Lỗi phát video: ' + e.message, 'err');
-        URL.revokeObjectURL(blobUrl);
-      });
+      video.play().then(() => { let finished = false; function finish() { if (finished) return; finished = true; try { rec.requestData(); } catch(e) {} setTimeout(() => { if (rec.state !== 'inactive') rec.stop(); try { audioVideo.pause(); } catch(e) {} }, 300); } video.onended = finish; audioVideo.onended = finish; const expectedDur = (video.duration || 0) * 1000; if (expectedDur > 0 && isFinite(expectedDur)) { setTimeout(() => { if (!finished) finish(); }, expectedDur + 3000); } else { setTimeout(() => { if (!finished) finish(); }, 60000); } function draw() { if (video.paused || video.ended) return; ctx.drawImage(video, sx, sy, cw, ch, 0, 0, cw, ch); requestAnimationFrame(draw); } draw(); }).catch(e => { hideProc(); recStatus('❌ Lỗi phát video: ' + e.message, 'err'); URL.revokeObjectURL(blobUrl); });
     }
-
-    video.onerror = function() {
-      hideProc(); recStatus('❌ Không đọc được video.', 'err');
-      URL.revokeObjectURL(blobUrl);
-    };
-
+    video.onerror = function() { hideProc(); recStatus('❌ Không đọc được video.', 'err'); URL.revokeObjectURL(blobUrl); };
     video.addEventListener('loadedmetadata', onReady);
     video.addEventListener('canplay', onReady);
   }
 
-  // ===== TOGGLE REC PANEL =====
   function toggleRecPanel() {
     const panel = document.getElementById('vtv-inline-rec');
     if (!panel) { buildInlineRecorder(); setTimeout(toggleRecPanel, 200); return; }
@@ -715,17 +621,96 @@
     panel.classList.toggle('show', _rec.active);
     const btn = document.getElementById('vtv-rec-btn');
     if (btn) {
-      if (_rec.active) {
-        btn.style.background = '#3a1a1a';
-        btn.innerHTML = '<svg viewBox="0 0 24 24"><rect x="6" y="6" width="12" height="12" rx="2"/></svg> Đóng';
-      } else {
-        btn.style.background = '';
-        btn.innerHTML = '<svg viewBox="0 0 24 24"><circle cx="12" cy="12" r="8"/></svg> Record';
-        document.getElementById('vtv-rec-panel').classList.remove('show');
-      }
+      if (_rec.active) { btn.style.background = '#3a1a1a'; btn.innerHTML = '<svg viewBox="0 0 24 24"><rect x="6" y="6" width="12" height="12" rx="2"/></svg> Đóng'; }
+      else { btn.style.background = ''; btn.innerHTML = '<svg viewBox="0 0 24 24"><circle cx="12" cy="12" r="8"/></svg> Record'; document.getElementById('vtv-rec-panel').classList.remove('show'); }
     }
   }
 
+  // ===== DVR SEEK BAR =====
+  function buildDVRBar() {
+    const controls = document.querySelector('.vtv-controls');
+    if (!controls || document.getElementById('vtv-dvr-bar')) return;
+    const dvrBar = document.createElement('div');
+    dvrBar.id = 'vtv-dvr-bar';
+    dvrBar.className = 'vtv-dvr-bar';
+    dvrBar.innerHTML = `
+      <span class="vtv-dvr-label">⏪ DVR</span>
+      <div class="vtv-dvr-track" id="vtv-dvr-track">
+        <div class="vtv-dvr-buffer" id="vtv-dvr-buffer"></div>
+        <div class="vtv-dvr-live-dot" id="vtv-dvr-live-dot"></div>
+        <div class="vtv-dvr-handle" id="vtv-dvr-handle"></div>
+      </div>
+      <span class="vtv-dvr-time" id="vtv-dvr-time">LIVE</span>
+      <button class="vtv-dvr-live-btn" id="vtv-dvr-live-btn" title="Quay về LIVE">LIVE</button>
+    `;
+    controls.parentNode.insertBefore(dvrBar, controls);
+
+    // DVR seek interactions
+    const track = document.getElementById('vtv-dvr-track');
+    const handle = document.getElementById('vtv-dvr-handle');
+    const liveDot = document.getElementById('vtv-dvr-live-dot');
+    const buffer = document.getElementById('vtv-dvr-buffer');
+    const timeLabel = document.getElementById('vtv-dvr-time');
+    const liveBtn = document.getElementById('vtv-dvr-live-btn');
+    let isDragging = false;
+
+    function updateDVRUI() {
+      const video = document.getElementById('vtv-player');
+      if (!video || !_hls) return;
+      const curTime = video.currentTime;
+      const duration = video.duration;
+      if (!duration || !isFinite(duration)) return;
+      const bufferStart = Math.max(0, duration - DVR_BUFFER_SECONDS);
+      const bufferWidth = ((duration - bufferStart) / DVR_BUFFER_SECONDS) * 100;
+      const handlePos = ((curTime - bufferStart) / (duration - bufferStart)) * 100;
+      buffer.style.width = Math.min(100, bufferWidth) + '%';
+      buffer.style.left = (100 - Math.min(100, bufferWidth)) + '%';
+      liveDot.style.left = '100%';
+      handle.style.left = Math.max(0, Math.min(100, handlePos)) + '%';
+      const behind = duration - curTime;
+      if (behind < 3) { timeLabel.textContent = 'LIVE'; timeLabel.style.color = '#e74c3c'; }
+      else { timeLabel.textContent = '-' + fmtSec(behind); timeLabel.style.color = '#8ab4d8'; }
+    }
+
+    function seekFromTrack(clientX) {
+      const video = document.getElementById('vtv-player');
+      if (!video || !_hls) return;
+      const rect = track.getBoundingClientRect();
+      const pct = Math.max(0, Math.min(1, (clientX - rect.left) / rect.width));
+      const duration = video.duration;
+      if (!duration || !isFinite(duration)) return;
+      const bufferStart = Math.max(0, duration - DVR_BUFFER_SECONDS);
+      const seekTime = bufferStart + pct * (duration - bufferStart);
+      video.currentTime = seekTime;
+      updateDVRUI();
+    }
+
+    track.addEventListener('click', function(e) { seekFromTrack(e.clientX); });
+    track.addEventListener('touchstart', function(e) { e.preventDefault(); seekFromTrack(e.touches[0].clientX); }, {passive: false});
+
+    handle.addEventListener('mousedown', function(e) { e.preventDefault(); e.stopPropagation(); isDragging = true; });
+    handle.addEventListener('touchstart', function(e) { e.preventDefault(); e.stopPropagation(); isDragging = true; }, {passive: false});
+
+    document.addEventListener('mousemove', function(e) { if (isDragging) { e.preventDefault(); seekFromTrack(e.clientX); } });
+    document.addEventListener('touchmove', function(e) { if (isDragging) { e.preventDefault(); seekFromTrack(e.touches[0].clientX); } }, {passive: false});
+    document.addEventListener('mouseup', function() { isDragging = false; });
+    document.addEventListener('touchend', function() { isDragging = false; });
+
+    liveBtn.addEventListener('click', function() {
+      const video = document.getElementById('vtv-player');
+      if (video && _hls) { video.currentTime = video.duration; updateDVRUI(); }
+    });
+
+    // Update UI periodically
+    if (_dvrSeekBarTimer) clearInterval(_dvrSeekBarTimer);
+    _dvrSeekBarTimer = setInterval(updateDVRUI, 1000);
+  }
+
+  function showDVRBar() {
+    const bar = document.getElementById('vtv-dvr-bar');
+    if (bar) bar.classList.add('visible');
+  }
+
   // ===== PIN BUTTON =====
   function setupPinButton(){
     const block = document.getElementById('vtv-block');
@@ -807,7 +792,7 @@
   function pinBlock(){
     const h=document.getElementById('view-home'); if(!h||document.getElementById('vtv-block')) return;
     h.insertBefore(buildBlock(),h.firstChild); _blockInserted=true;
-    setTimeout(()=>{setupPinButton();buildInlineRecorder();},500);
+    setTimeout(()=>{setupPinButton();buildInlineRecorder();buildDVRBar();},500);
     if(!_streamsLoaded){loadAllStreams().then(()=>{setTimeout(()=>window._vtvPlay(DEFAULT_CHANNEL),300);});}
   }
 
@@ -826,13 +811,23 @@
     _tryPlay(video,urls,0,ch.name,loadEl,errEl,errMsg);
     loadEpg(chId);
     if(_miniActive){document.getElementById('vtv-mini-ch').textContent=ch.name;fetch('/api/vtv/epg/'+_currentCh).then(r=>r.json()).then(d=>{const p=d.programs||[];const n=p.find(x=>x.now);document.getElementById('vtv-mini-epg').textContent=n?n.time+' '+n.title:(p[0]?p[0].time+' '+p[0].title:'');}).catch(()=>{});}
+    // Show DVR bar after stream loads
+    setTimeout(()=>{showDVRBar();},2000);
   };
 
   function _tryPlay(video,urls,idx,name,loadEl,errEl,errMsg){
     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()){
-      const hls=new Hls({enableWorker:true,lowLatencyMode:false,startLevel:0,capLevelToPlayerSize:true,maxBufferLength:6,maxMaxBufferLength:10,liveSyncDurationCount:2,liveMaxLatencyDurationCount:3,fragLoadingTimeOut:10000,manifestLoadingTimeOut:10000}); _hls=hls; hls.loadSource(src); hls.attachMedia(video);
+      // v8: Add liveBackBufferLength for 5-min DVR buffer
+      const hls=new Hls({
+        enableWorker:true,lowLatencyMode:false,startLevel:0,capLevelToPlayerSize:true,
+        maxBufferLength:60,maxMaxBufferLength:120,
+        liveBackBufferLength:DVR_BUFFER_SECONDS,
+        liveSyncDurationCount:2,liveMaxLatencyDurationCount:5,
+        fragLoadingTimeOut:10000,manifestLoadingTimeOut:10000
+      });
+      _hls=hls; hls.loadSource(src); hls.attachMedia(video);
       hls.on(Hls.Events.MANIFEST_PARSED,()=>{video.play().catch(()=>{});loadEl.style.display='none';video.style.display='block';});
       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')){