feat: ARM multitrack mỗi track dùng MIDI channel riêng (0-15, trừ 9) - không làm đổi instrument track khác, lưu midi_channel khi save project

app/static/js/app.jsx

@@ -4637,7 +4637,7 @@ const ProfileModal = ({
       if (!sfId) continue;
       const bank = se ? (se.soundfont_bank !== undefined ? se.soundfont_bank : 0) : (t.soundfont_bank !== undefined ? t.soundfont_bank : 0);
       const prog = se ? (se.soundfont_program !== undefined ? se.soundfont_program : 0) : (t.soundfont_program !== undefined ? t.soundfont_program : 0);
-      var ch = window.SonicPianoRoll ? window.SonicPianoRoll.getTrackMidiChannel(t, tracks) : (t.midiChannel !== undefined ? t.midiChannel : 0);
+      var ch = t && assignTrackMidiChannel(t, tracks);
       try {
         await window.SonicSF.selectInstrument(ch, bank, prog, sfId);
       } catch (e) {}
@@ -4702,6 +4702,7 @@ const ProfileModal = ({
           }
           setTracks(restoredTracks);
           loadAudioBuffersForTracks(restoredTracks).catch(function(err) { console.warn('loadAudioBuffersForTracks error:', err); });
+          trackMidiChannelsRef.current = {};
           preloadTrackInstruments(restoredTracks).catch(function(err) { console.warn('preloadTrackInstruments error:', err); });
           setBpm(restoredBpm.toString());
           setSelectedTrackId(restoredTracks[0]?.id || '1');
@@ -7888,6 +7889,7 @@ const serializeTracksList = (tracksList, secondsPerBar) => {
       soundfont_bank: t.soundfont_bank !== undefined ? t.soundfont_bank : (t.synth_engine ? t.synth_engine.soundfont_bank : null),
       soundfont_program: t.soundfont_program !== undefined ? t.soundfont_program : (t.synth_engine ? t.synth_engine.soundfont_program : null),
       synth_engine: t.synth_engine || undefined,
+      midi_channel: t.midiChannel !== undefined ? t.midiChannel : null,
       server_file_id: t.serverFileId || null,
       items: items
     };
@@ -11088,10 +11090,41 @@ const App = () => {
     "Tinkle Bell","Agogo","Steel Drums","Woodblock","Taiko Drum","Melodic Tom","Synth Drum","Reverse Cymbal",
     "Guitar Fret Noise","Breath Noise","Seashore","Bird Tweet","Telephone Ring","Helicopter","Applause","Gunshot"
   ];
+  // ── Dedicated per-track MIDI channel allocation ──
+  // FluidSynth has 16 channels; if two tracks share a channel, arming one track
+  // re-selects the other track's program and its instrument changes. Every track
+  // gets its own stable, unique channel (0-15, skipping 9 which is the classic
+  // percussion slot) so multi-track ARM never cross-contaminates instruments.
+  const trackMidiChannelsRef = useRef({});
+  const ensureTrackMidiChannel = (track, tracks) => {
+    if (!track) return 0;
+    const trackList = tracks || [];
+    const inUse = new Set();
+    trackList.forEach(tr => { if (tr && tr.id !== track.id && tr.midiChannel !== undefined) inUse.add(tr.midiChannel); });
+    const cached = trackMidiChannelsRef.current[track.id];
+    if (cached !== undefined && !inUse.has(cached)) return cached;
+    const preferred = track.midiChannel !== undefined && !inUse.has(track.midiChannel) ? track.midiChannel : null;
+    if (preferred !== null) { trackMidiChannelsRef.current[track.id] = preferred; return preferred; }
+    for (let c = 0; c < 16; c++) {
+      if (c === 9) continue;
+      if (!inUse.has(c)) { trackMidiChannelsRef.current[track.id] = c; return c; }
+    }
+    trackMidiChannelsRef.current[track.id] = 0;
+    return 0;
+  };
+  const assignTrackMidiChannel = (track, tracks) => {
+    const ch = ensureTrackMidiChannel(track, tracks);
+    if (track && track.midiChannel !== ch) track.midiChannel = ch;
+    return ch;
+  };
   const setTrackInstrumentWithProgram = (trackId, instrumentId, programNumber, displayName, bankNumber) => {
     const isSfInstrument = instrumentId && typeof instrumentId === 'string' && instrumentId.startsWith('sf_');
     const sfBank = bankNumber !== undefined ? bankNumber : (isSfInstrument ? 0 : undefined);
     const sfProg = programNumber !== undefined ? programNumber : undefined;
+    var mt = activeTracksRef.current || tracks;
+    var curTrk = null;
+    for (var ci = 0; ci < mt.length; ci++) { if (mt[ci].id === trackId) { curTrk = mt[ci]; break; } }
+    var mch = curTrk ? assignTrackMidiChannel(curTrk, mt) : (sfBank === 128 ? 9 : 0);
     updateActiveTracks(prev => prev.map(t => {
       if (t.id !== trackId) return t;
       const hasInstrument = !!instrumentId;
@@ -11103,10 +11136,6 @@ const App = () => {
         soundfont_program: sfProg !== undefined ? sfProg : 0,
         soundfont_id: isSfInstrument ? instrumentId.replace('sf_', '') : ''
       } : undefined;
-      var mt = activeTracksRef.current || tracks;
-      var midx = 0;
-      for (var mi = 0; mi < mt.length; mi++) { if (mt[mi].id === trackId) { midx = mi; break; } }
-      var mch = sfBank === 128 ? 9 : (midx % 16);
       return { ...t, midiChannel: mch, instrumentId, instrumentProgram: sfProg, instrumentName: displayName, soundfont_bank: sfBank, soundfont_program: sfProg, synth_engine: synthEngine, type: hasInstrument ? 'MIDI' : (t.type === 'MIDI' ? 'audio' : t.type) };
     }));
     setInstrumentDropdownTrackId(null);
@@ -11115,15 +11144,7 @@ const App = () => {
     // Trigger SpessaSynth load + program change when soundfont instrument selected
     if (window.SonicSF && window.SonicSF.selectInstrument && instrumentId && isSfInstrument) {
       const sfId = instrumentId.replace('sf_', '');
-      var allTracks = activeTracksRef.current || tracks;
-      var tidx = 0;
-      for (var i = 0; i < allTracks.length; i++) { if (allTracks[i].id === trackId) { tidx = i; break; } }
-      var ch = sfBank === 128 ? 9 : (tidx % 16);
-      // Store channel for consistent per-track instrument playback
-      if (!allTracks[tidx] || allTracks[tidx].midiChannel === undefined) {
-        updateActiveTracks(prev => prev.map(t => t.id === trackId ? { ...t, midiChannel: ch } : t));
-      }
-      window.SonicSF.selectInstrument(ch, sfBank || 0, sfProg || 0, sfId);
+      window.SonicSF.selectInstrument(mch, sfBank || 0, sfProg || 0, sfId);
     }
     setSubTabs(prev => prev.map(s => {
       if (s.trackId !== trackId) return s;
@@ -11168,11 +11189,15 @@ const App = () => {
     setInstrumentDropdownBtnRect(null);
     if (instrumentId && instrumentId.startsWith('sf_')) {
       // Set instrument on track immediately so Synth button shows the name
+      var mt2 = activeTracksRef.current || tracks;
+      var qTrk = null;
+      for (var qi = 0; qi < mt2.length; qi++) { if (mt2[qi].id === trackId) { qTrk = mt2[qi]; break; } }
+      var qch = qTrk ? assignTrackMidiChannel(qTrk, mt2) : 0;
       updateActiveTracks(prev => prev.map(t => {
         if (t.id !== trackId) return t;
         const sfClean = instrumentId.replace('sf_', '');
         const synthEngine = { type: 'soundfont', plugin_id: instrumentId, soundfont_bank: 0, soundfont_program: 0, soundfont_id: sfClean };
-        return { ...t, instrumentId, instrumentProgram: undefined, instrumentName: displayName, synth_engine: synthEngine };
+        return { ...t, midiChannel: qch, instrumentId, instrumentProgram: undefined, instrumentName: displayName, synth_engine: synthEngine };
       }));
       setSelectedSoundFontId(instrumentId);
       setSynthCategory('soundfont');
@@ -11297,7 +11322,7 @@ const App = () => {
                      if (arSubs.length > 0) {
                        arSubs.forEach(function(as) {
                          var asTrk = allTracks.find(function(t) { return t.id === as.trackId; });
-                         var asCh = window.SonicPianoRoll ? window.SonicPianoRoll.getTrackMidiChannel(asTrk, allTracks) : (asTrk ? asTrk.midiChannel : 0);
+                         var asCh = asTrk ? assignTrackMidiChannel(asTrk, allTracks) : 0;
                          var asProg = as.instrumentProgram;
                          var asSe = as.synth_engine;
                           if (window.triggerMidiVuActivity) {
@@ -11308,7 +11333,7 @@ const App = () => {
                      }
                      // Route to ALL armed tracks (not just the first one)
                      armedTracks.forEach(function(at) {
-                       var atCh = window.SonicPianoRoll ? window.SonicPianoRoll.getTrackMidiChannel(at, allTracks) : (at.midiChannel !== undefined ? at.midiChannel : 0);
+                       var atCh = assignTrackMidiChannel(at, allTracks);
                        var atProg = at.instrumentProgram;
                        var atSe = at.synth_engine;
                        var atDest = activeTrackNodesRef.current[at.id]?.gainNode || null;
@@ -11329,13 +11354,17 @@ const App = () => {
                }
                 // Stop the note on ALL tracks (not just armed) to prevent stuck notes
                 // when ARM is toggled off while a key is held
-                if (window.SonicSF && window.SonicSF.stopNote) {
-                  var stopTracks = activeTracksRef.current || [];
-                  stopTracks.forEach(function(st) {
-                    var stCh = window.SonicPianoRoll ? window.SonicPianoRoll.getTrackMidiChannel(st, stopTracks) : (st.midiChannel !== undefined ? st.midiChannel : 0);
-                    window.SonicSF.stopNote(stCh, pitch);
-                  });
-                }
+                 if (window.SonicSF && window.SonicSF.stopNote) {
+                   var stopTracks = activeTracksRef.current || [];
+                   stopTracks.forEach(function(st) {
+                     // Only stop channels that actually carry this track's notes —
+                     // an index-based fallback could hit another track's dedicated
+                     // channel and kill its sound.
+                     if (!st.synth_engine && st.midiChannel === undefined) return;
+                     var stCh = assignTrackMidiChannel(st, stopTracks);
+                     window.SonicSF.stopNote(stCh, pitch);
+                   });
+                 }
               }
 
             // ── Sustain (CC64), Modulation (CC1), Pitch Bend ──
@@ -11348,11 +11377,11 @@ const App = () => {
                 var ccTracks = activeTracksRef.current || [];
                 var hasArmed = ccTracks.some(function(t) { return t.isArmed; });
                 if (hasArmed) {
-                  ccTracks.forEach(function(ct) {
-                    if (!ct.isArmed) return;
-                    var ctCh = window.SonicPianoRoll ? window.SonicPianoRoll.getTrackMidiChannel(ct, ccTracks) : (ct.midiChannel !== undefined ? ct.midiChannel : 0);
-                    window.SonicSF.controllerChange(ctCh, cc, val);
-                  });
+                   ccTracks.forEach(function(ct) {
+                     if (!ct.isArmed) return;
+                     var ctCh = assignTrackMidiChannel(ct, ccTracks);
+                     window.SonicSF.controllerChange(ctCh, cc, val);
+                   });
                 } else {
                   window.SonicSF.controllerChange(midiCh, cc, val);
                 }
@@ -11366,11 +11395,11 @@ const App = () => {
                 var pbTracks = activeTracksRef.current || [];
                 var hasArmedPB = pbTracks.some(function(t) { return t.isArmed; });
                 if (hasArmedPB) {
-                  pbTracks.forEach(function(pt) {
-                    if (!pt.isArmed) return;
-                    var ptCh = window.SonicPianoRoll ? window.SonicPianoRoll.getTrackMidiChannel(pt, pbTracks) : (pt.midiChannel !== undefined ? pt.midiChannel : 0);
-                    window.SonicSF.pitchBend(ptCh, bendVal);
-                  });
+                   pbTracks.forEach(function(pt) {
+                     if (!pt.isArmed) return;
+                     var ptCh = assignTrackMidiChannel(pt, pbTracks);
+                     window.SonicSF.pitchBend(ptCh, bendVal);
+                   });
                 } else {
                   window.SonicSF.pitchBend(midiCh, bendVal);
                 }
@@ -12128,6 +12157,7 @@ const App = () => {
       }
       setTracks(restoredTracks);
       loadAudioBuffersForTracks(restoredTracks).catch(function(err) { console.warn('loadAudioBuffersForTracks error:', err); });
+      trackMidiChannelsRef.current = {};
       preloadTrackInstruments(restoredTracks).catch(function(err) { console.warn('preloadTrackInstruments error:', err); });
       setBpm(restoredBpm.toString());
       setSelectedTrackId(restoredTracks[0]?.id || '1');

app/templates/index.html

@@ -24,7 +24,7 @@
     <script src="/static/js/services/midiExtractor.js?v=202607281052"></script>
     <script src="/static/js/services/promptTemplateManager.js?v=202607281039"></script>
     <script src="/static/js/services/undoRedoEngine.js?v=202607290941"></script>
-    <script src="/static/js/app.precompiled.js?v=202608031040" defer></script>
+    <script src="/static/js/app.precompiled.js?v=202608031100" defer></script>
     <link rel="stylesheet" href="/static/css/styles.css?v=202607271016">
     <style>
         :root {

wiki.md

@@ -1209,3 +1209,8 @@
 - **Tóm tắt thay đổi:** (1) **Dedup load soundfont**: `loadSoundFont` trước đây không chặn các lệnh gọi đồng thời — nhấn phím MIDI liên tục (hoặc nhiều track ARM) kích hoạt lazy-load cùng lúc → SGM-V2.01 bị `sfload` 4 lần (handle 1,2,3,4 trong log), mỗi bản ~52MB trong heap WASM 256MB → cạn bộ nhớ, các lần load sau fail → câm sau vài lần nhấn + mỗi note chờ load (lag). Thêm `_loadPromises[sfId]` dedup (1 font = 1 lần load, cache cả kết quả fail) + `_sfloadSeq` cho filename temp duy nhất tránh trùng tên khi load 2 font khác nhau đồng thời. (2) **Preload instrument khi mở/khôi phục dự án**: thêm `preloadTrackInstruments(tracks)` gọi `selectInstrument` cho từng track có soundfont ngay sau khi `setTracks` trong `handleOpenProject` và `restoreLastSessionProject` → nhấn MIDI key đầu tiên không còn lag (font đã nạp sẵn).
 - **Các file ảnh hưởng:** `app/static/js/services/soundfontPlayer.js`, `app/static/js/app.jsx`, `app/static/js/app.precompiled.js` (build lại), `app/templates/index.html`
 - **Ghi chú/Test (nếu có):** `npm run build` (babel) OK, bundle chứa `preloadTrackInstruments`. Harness `node /tmp/kilo/test_dedup.js`: 8 lần `loadSoundFont` cùng 1 font đồng thời → chỉ 1 `sfload`, 1 lần đọc cache; load lại font đã nạp → 0 sfload; 2 font khác nhau đồng thời → đúng 2 sfload — ALL PASSED. `test_sonicsf_fix.js` + `test_multi_track.js` vẫn ALL PASSED. Hard refresh trình duyệt.
+
+### [2026-08-03 11:00] Task: ARM multitrack - mỗi track dùng channel MIDI riêng, không làm đổi instrument track khác
+- **Tóm tắt thay đổi:** FluidSynth có 16 channel; nếu 2 track trùng channel thì ARM track này sẽ `program_select` đè instrument của track kia. Thêm cơ chế channel riêng cho từng track trong app.jsx: `trackMidiChannelsRef` + `ensureTrackMidiChannel`/`assignTrackMidiChannel` cấp channel ổn định, duy nhất (0-15, bỏ qua 9 - slot percussion cổ điển), tự sửa khi 2 track trùng channel được lưu. Áp dụng ở mọi nơi tính channel: `setTrackInstrumentWithProgram`, `setTrackInstrument` (dropdown nhanh), `preloadTrackInstruments`, routing ARM note-on (armedTracks + piano-roll sub-tab), note-off/CC/PitchBend (bỏ fallback `index % 16` — tránh dừng nhầm note của track khác). Lưu `midi_channel` khi save project + restore; reset map channel khi mở/khôi phục dự án. Kết hợp doNote cũ (synth_engine quyết định + re-select trước noteon) → mỗi track luôn phát đúng instrument của nó dù ARM nhiều track, chord/hợp âm đồng thời không còn đổi âm sắc nhau.
+- **Các file ảnh hưởng:** `app/static/js/app.jsx`, `app/static/js/app.precompiled.js` (build lại), `app/templates/index.html`
+- **Ghi chú/Test (nếu có):** `npm run build` OK, bundle chứa `assignTrackMidiChannel` (8 chỗ). Harness `node /tmp/kilo/test_channels.js`: 3 track → channel 0,1,2 duy nhất; gọi lại ổn định; track mới lấy channel trống; track lưu trùng channel được cấp lại; track lưu channel duy nhất được giữ; percussion giữ 9 + track trống khác lấy channel riêng — ALL PASSED. 3 harness cũ (single/multi/dedup) vẫn PASS. Hard refresh.