M20: diag Bug B — log meter dB master OUT (load/fx_click/panel_open + hist 8s + post 1/2/4/8s)

app/static/js/app.jsx

@@ -272,6 +272,67 @@ const _dbgLog = (tag, extra) => {
 };
 // V29: expose dbg hook cho BridgeAudioNode (worklet state) + helpers.
 window.__dbgLog = _dbgLog;
+// M20 Bug B diag: log dB meter master OUT (masterBus.analyser — cùng nguồn
+// outPeakText MASTERING PANEL, SAU chain FX) + fader gain state. Hist vòng ~8s
+// @250ms (chỉ giữ RAM, không log cho tới khi có event); marker: load (initMasterBus),
+// fx_click (nút FX master), panel_open + post 1/2/4/8s (MASTERING PANEL mở) →
+// so dB trước/sau để tìm cơ chế Bug B (âm lượng giảm khi mở panel).
+let _mdiagHist = [];
+let _mdiagTimer = null;
+let _mdiagBuf = null;
+function _mdiagDb() {
+  try {
+    const b = window.masterBus;
+    if (!b || !b.analyser) return null;
+    const an = b.analyser;
+    const len = an.fftSize || 2048;
+    if (!_mdiagBuf || _mdiagBuf.length < len) _mdiagBuf = new Float32Array(len);
+    an.getFloatTimeDomainData(_mdiagBuf);
+    let pk = 0;
+    for (let i = 0; i < len; i++) { const v = _mdiagBuf[i]; const a = v < 0 ? -v : v; if (a > pk) pk = a; }
+    return pk < 0.00003 ? -120 : 20 * Math.log10(pk);
+  } catch (e) { return null; }
+}
+function _mdiagFader() {
+  try {
+    const b = window.masterBus; if (!b) return 'na';
+    const f = (x) => { try { const n = x && x.gain ? x.gain.value : null; return n === null ? 'na' : n.toFixed(4); } catch (e) { return 'na'; } };
+    return 'out=' + f(b.output) + ' mute=' + f(b.muteGain) + ' volL=' + f(b.volLGain) + ' volR=' + f(b.volRGain);
+  } catch (e) { return 'na'; }
+}
+function _mdiagSample(tag) {
+  const db = _mdiagDb();
+  try { _dbgLog('mdiag_' + tag, 'db=' + (db === null ? 'na' : db.toFixed(1)) + ' ' + _mdiagFader()); } catch (e) {}
+}
+function _mdiagStart() {
+  if (_mdiagTimer) return;
+  _mdiagTimer = setInterval(() => {
+    try {
+      if (!window.masterBus) return;
+      _mdiagHist.push(_mdiagDb());
+      if (_mdiagHist.length > 32) _mdiagHist.shift(); // ~8s @250ms
+    } catch (e) {}
+  }, 250);
+}
+function _mdiagDump() {
+  try {
+    for (let i = 0; i < _mdiagHist.length; i++) {
+      const v = _mdiagHist[i];
+      _dbgLog('mdiag_hist', 'db=' + (v === null ? 'na' : v.toFixed(1)));
+    }
+  } catch (e) {}
+}
+let _mdiagPostTimer = null;
+function _mdiagSchedulePost() {
+  if (_mdiagPostTimer) clearTimeout(_mdiagPostTimer);
+  const del = [1000, 2000, 4000, 8000];
+  let k = 0;
+  const tick = () => {
+    if (k >= del.length) return;
+    _mdiagPostTimer = setTimeout(() => { _mdiagSample('post' + del[k]); k++; tick(); }, del[k]);
+  };
+  tick();
+}
 if (window.PerformanceObserver) { try { new PerformanceObserver((list) => { for (const e of list.getEntries()) _dbgLog('longtask', 'd=' + Math.round(e.duration) + ' s=' + Math.round(e.startTime)); }).observe({ entryTypes: ['longtask'] }); } catch (e) {} }
 const _dbgBridgeGain = () => {
   try {
@@ -1324,6 +1385,7 @@ function initMasterBus(ctx) {
   masterBus.analyser.connect(ctx.destination);
 
   window.masterBus = masterBus;
+  try { _mdiagStart(); setTimeout(() => _mdiagSample('load1'), 1000); setTimeout(() => _mdiagSample('load5'), 5000); } catch (e) {}
   // Apply mastering once when the chain is first created (and on the
   // masteringSettings effect for subsequent changes — see useEffect).
   if (window.currentMasteringSettings) {
@@ -3610,7 +3672,7 @@ const MasterStripConsole = ({ masterVolume, setMasterVolume, masterVolL, setMast
         React.createElement("button", {
           id: "fxBtn",
           className: "btn-daw h-[18px] rounded font-extrabold text-[10px] transition-all",
-          onClick: function() { setShowMasteringModal(true); },
+          onClick: function() { try { _mdiagSample('fx_click'); } catch (e) {} setShowMasteringModal(true); },
           title: "Mở MASTER FX CHAIN để chỉnh sửa"
         }, "FX"),
         React.createElement("button", {
@@ -14801,6 +14863,8 @@ const MasteringModal = ({ isOpen, onClose, masteringSettings, setMasteringSettin
   }, []);
   React.useEffect(() => {
     if (!isOpen) { _autoOpenRef.current.attempt = 0; return; }
+    // M20 Bug B diag: giá trị meter đúng lúc mở MASTERING PANEL + hist 8s trước + post 1/2/4/8s
+    try { _mdiagSample('panel_open'); _mdiagDump(); _mdiagSchedulePost(); } catch (e) {}
     if (_autoOpenRef.current.timer) { clearTimeout(_autoOpenRef.current.timer); _autoOpenRef.current.timer = null; }
     _autoTryOpen();
     // eslint-disable-next-line react-hooks/exhaustive-deps