feat(engine): fix SF2 path resolution, add synth_engine struct and fallback chain

- Fix SF2 path: search upload dir, system dir, static dir (backward compat)
- Add synth_engine struct parsing with flat field fallback
- Add 3-level fallback: selected SF -> default SF -> oscillator synth
- Write synth_engine in setTrackInstrument UI setters
- Pass synth_engine context to client SoundFontPlayer and AI gateway

app/core/render_engine.py

@@ -1,4 +1,4 @@
-import os
+import os, logging
 import numpy as np
 import soundfile as sf
 import scipy.signal as signal
@@ -11,6 +11,43 @@ from app.core.vst_engine import (
     HAS_PYFLUIDSYNTH,
 )
 
+logger = logging.getLogger(__name__)
+
+UPLOAD_SF_DIR = os.path.join(settings.STORAGE_DIR, "soundfonts")
+SYSTEM_SF_DIR = "/opt/daw_engine/soundfonts"
+
+SYS_SOUNDFONTS = [
+    ("GeneralUser_GS.sf2", "GeneralUser GS"),
+    ("SGM_v2.01.sf2", "SGM v2.01"),
+    ("SGM-V2.01.sf2", "SGM v2.01"),
+]
+
+def _find_sf2_path(sf_id: str) -> str:
+    clean_id = sf_id.replace("sf_", "") if sf_id.startswith("sf_") else sf_id
+    for base_dir in [UPLOAD_SF_DIR, SYSTEM_SF_DIR]:
+        if not os.path.isdir(base_dir):
+            continue
+        for fname in os.listdir(base_dir):
+            fbase, fext = os.path.splitext(fname)
+            if fext.lower() in (".sf2", ".sf3") and (fbase == clean_id or fbase == sf_id):
+                return os.path.join(base_dir, fname)
+    # Backward compat: static/soundfonts
+    static_dir = os.path.join(settings.APP_DIR, "static", "soundfonts")
+    if os.path.isdir(static_dir):
+        for fname in os.listdir(static_dir):
+            fbase, fext = os.path.splitext(fname)
+            if fext.lower() in (".sf2", ".sf3") and (fbase == clean_id or fbase == sf_id):
+                return os.path.join(static_dir, fname)
+    return ""
+
+def _find_default_sf2() -> str:
+    for sf_name, _ in SYS_SOUNDFONTS:
+        for base_dir in [SYSTEM_SF_DIR, UPLOAD_SF_DIR]:
+            p = os.path.join(base_dir, sf_name)
+            if os.path.exists(p):
+                return p
+    return ""
+
 if HAS_PEDALBOARD:
     try:
         from pedalboard import Pedalboard, Gain, Chorus, Reverb
@@ -58,8 +95,13 @@ class PythonRenderEngine:
             track_type = track.get("type", "AUDIO")
             track_buffer = np.zeros((2, total_samples), dtype=np.float32)
 
-            soundfont_bank = track.get("soundfont_bank", 0)
+            # Parse synth_engine struct (Task C) — fall back to flat fields
-            soundfont_program = track.get("soundfont_program", 0)
+            se = track.get("synth_engine", {}) or {}
+            instrument_id = se.get("plugin_id") or track.get("instrument_id", "") or track.get("instrument", "")
+            instrument_source = se.get("type") or track.get("instrument_source", "soundfont")
+            soundfont_bank = se.get("soundfont_bank") if se.get("soundfont_bank") is not None else track.get("soundfont_bank", 0)
+            soundfont_program = se.get("soundfont_program") if se.get("soundfont_program") is not None else track.get("soundfont_program", 0)
+            soundfont_id = se.get("soundfont_id") or track.get("soundfont_id", "")
             is_percussion = track.get("is_percussion", False) or (soundfont_bank == 128)
             midi_channel = 9 if is_percussion else (_channel_counter % 9)
             if not is_percussion:
@@ -130,12 +172,9 @@ class PythonRenderEngine:
                     
                     if midi_events:
                         try:
-                            instrument_id = track.get("instrument_id", "") or track.get("instrument", "")
                             plugin_mgr = PluginManager()
                             vst = plugin_mgr.load_vst(instrument_id) if instrument_id else None
 
-                            instrument_source = track.get("instrument_source", "soundfont")
-
                             if instrument_source == "pianobook":
                                 dspreset_path = track.get("dspreset_path", "")
                                 if dspreset_path and os.path.exists(dspreset_path) and HAS_PEDALBOARD:
@@ -157,7 +196,7 @@ class PythonRenderEngine:
                                         board = Pedalboard([vst])
                                         synth_buffer = board(silent, sample_rate=self.sample_rate, midi_messages=midi_messages)
                                     except Exception as e:
-                                        print(f"[RenderEngine] DecentSampler/Pianobook error: {e}")
+                                        logger.warning(f"[RenderEngine] DecentSampler/Pianobook error: {e}")
                                         synth_buffer = render_midi_events_to_audio(
                                             midi_events=midi_events, sr=self.sample_rate, bpm=bpm, instrument='synth'
                                         )
@@ -167,7 +206,6 @@ class PythonRenderEngine:
                                     )
                             elif vst and HAS_PEDALBOARD:
                                 from pedalboard import Pedalboard
-                                # Convert MIDI events with precise sample offset
                                 midi_messages = PluginManager.midi_events_to_messages(
                                     midi_events, bpm, self.sample_rate,
                                     bank=soundfont_bank, program=soundfont_program
@@ -182,12 +220,15 @@ class PythonRenderEngine:
                                 silent = np.zeros((2, total_needed), dtype=np.float32)
                                 board = Pedalboard([vst])
                                 synth_buffer = board(silent, sample_rate=self.sample_rate, midi_messages=midi_messages)
-                            elif instrument_id and instrument_id.startswith("sf_"):
+                            elif instrument_id and (instrument_id.startswith("sf_") or soundfont_id):
-                                sf_path = os.path.join(
+                                sf_path = _find_sf2_path(soundfont_id or instrument_id)
-                                    os.path.dirname(os.path.dirname(__file__)), "static", "soundfonts",
+                                # 3-level fallback: selected SF → default SF → oscillator synth
-                                    instrument_id.replace("sf_", "") + ".sf2"
+                                if not sf_path or not os.path.exists(sf_path) or not HAS_PYFLUIDSYNTH:
-                                )
+                                    if not sf_path or not os.path.exists(sf_path):
-                                if os.path.exists(sf_path) and HAS_PYFLUIDSYNTH:
+                                        logger.warning(f"[RenderEngine] SoundFont not found for {soundfont_id or instrument_id}, trying default")
+                                    sf_path = _find_default_sf2() if HAS_PYFLUIDSYNTH else ""
+
+                                if sf_path and os.path.exists(sf_path) and HAS_PYFLUIDSYNTH:
                                     import fluidsynth
                                     fl = fluidsynth.FluidSynth(sample_rate=self.sample_rate, gain=0.5)
                                     fid = fl.sfload(sf_path)
@@ -198,8 +239,8 @@ class PythonRenderEngine:
                                         end_sec = (ev.get("start_beat", 0) + ev.get("duration_beats", 1)) * beat_sec
                                         if end_sec > total_sec:
                                             total_sec = end_sec
-                                    total_samples = int((total_sec + 1.0) * self.sample_rate)
+                                    sf_total_samples = int((total_sec + 1.0) * self.sample_rate)
-                                    midi_data = np.zeros((2, total_samples), dtype=np.float32)
+                                    midi_data = np.zeros((2, sf_total_samples), dtype=np.float32)
                                     for ev in midi_events:
                                         note = ev.get("note", 60)
                                         velocity = ev.get("velocity", 100)
@@ -213,13 +254,15 @@ class PythonRenderEngine:
                                         block = fl.get_samples(int(dur_s)) if hasattr(fl, 'get_samples') else np.zeros((2, dur_s), dtype=np.float32)
                                         fl.noteoff(midi_channel, note)
                                         if block.shape[1] > 0:
-                                            end_s = min(start_s + block.shape[1], total_samples)
+                                            end_s = min(start_s + block.shape[1], sf_total_samples)
                                             actual = end_s - start_s
                                             if actual > 0:
                                                 midi_data[:, start_s:end_s] += block[:, :actual]
                                     synth_buffer = midi_data
                                     fl.delete()
                                 else:
+                                    if not HAS_PYFLUIDSYNTH:
+                                        logger.warning("[RenderEngine] pyfluidsynth not available, falling back to oscillator synth")
                                     synth_buffer = render_midi_events_to_audio(
                                         midi_events=midi_events, sr=self.sample_rate, bpm=bpm, instrument='synth'
                                     )

app/static/js/app.jsx

@@ -6492,7 +6492,17 @@ const App = () => {
       if (t.id !== trackId) return t;
       const hasInstrument = !!instrumentId;
       const isSfInstrument = instrumentId && typeof instrumentId === 'string' && instrumentId.startsWith('sf_');
-      return { ...t, instrumentId, instrumentProgram: programNumber !== undefined ? programNumber : undefined, instrumentName: displayName, soundfont_bank: bankNumber !== undefined ? bankNumber : (isSfInstrument ? 0 : undefined), soundfont_program: programNumber !== undefined ? programNumber : undefined, type: hasInstrument ? 'MIDI' : (t.type === 'MIDI' ? 'audio' : t.type) };
+      const sfBank = bankNumber !== undefined ? bankNumber : (isSfInstrument ? 0 : undefined);
+      const sfProg = programNumber !== undefined ? programNumber : undefined;
+      const instrType = isSfInstrument ? 'soundfont' : (hasInstrument ? 'vst3' : 'default');
+      const synthEngine = hasInstrument ? {
+        type: instrType,
+        plugin_id: instrumentId,
+        soundfont_bank: sfBank !== undefined ? sfBank : 0,
+        soundfont_program: sfProg !== undefined ? sfProg : 0,
+        soundfont_id: isSfInstrument ? instrumentId.replace('sf_', '') : ''
+      } : undefined;
+      return { ...t, 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);
     setInstrumentDropdownBtnRect(null);
@@ -6544,7 +6554,9 @@ const App = () => {
       // Set instrument on track immediately so Synth button shows the name
       updateActiveTracks(prev => prev.map(t => {
         if (t.id !== trackId) return t;
-        return { ...t, instrumentId, instrumentProgram: undefined, instrumentName: displayName };
+        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 };
       }));
       setSelectedSoundFontId(instrumentId);
       setSynthCategory('soundfont');
@@ -10053,6 +10065,7 @@ const App = () => {
     const track = activeTracksRef.current ? activeTracksRef.current.find(t => t.id === st.trackId) : null;
     const destNode = getOrCreateTrackNode(track, context);
     const instrumentProgram = track ? track.instrumentProgram : undefined;
+    const synthEngine = track ? track.synth_engine : undefined;
     midiNotes.forEach(note => {
       const noteOnBeat = note.start_beat || 0;
       const noteDurBeat = note.duration_beats || 1;
@@ -10064,7 +10077,7 @@ const App = () => {
         const scheduledTime = startWallTime + effectiveStart;
         const durMs = effectiveDur * 1000;
         if (window.SonicSF) {
-          window.SonicSF.playNote(note.pitch || 60, note.velocity || 0.8, durMs, scheduledTime, instrumentProgram, destNode);
+          window.SonicSF.playNote(note.pitch || 60, note.velocity || 0.8, durMs, scheduledTime, instrumentProgram, destNode, undefined, synthEngine);
         }
       }
     });

app/static/js/services/aiGateway.js

@@ -218,6 +218,7 @@ Ví dụ: "Hãy chọn và copy từ bar 4 đến bar 12 của track 1 sau đó
   function buildAIPromptContext(dawState) {
     const tracks = (dawState.tracks || []).map(t => {
       const clips = t.clips && t.clips.length > 0 ? t.clips : (t.buffer ? [{ id: 'default_' + t.id, name: t.name, startTime: t.startTime || 0, duration: t.buffer.duration }] : []);
+      const se = t.synth_engine || null;
       return {
         id: t.id,
         name: t.name,
@@ -227,6 +228,7 @@ Ví dụ: "Hãy chọn và copy từ bar 4 đến bar 12 của track 1 sau đó
         solo: t.solo,
         volumeDb: t.volumeDb ?? 0,
         pan: t.pan ?? 0,
+        synth_engine: se ? { type: se.type, plugin_id: se.plugin_id, soundfont_bank: se.soundfont_bank, soundfont_program: se.soundfont_program, soundfont_id: se.soundfont_id } : undefined,
         clips: clips.map(c => ({ id: c.id, name: c.name, startTime: parseFloat((c.startTime || 0).toFixed(3)), duration: parseFloat((c.buffer ? c.buffer.duration : 0).toFixed(3)) }))
       };
     });

app/static/js/services/soundfontPlayer.js

@@ -57,7 +57,11 @@
             return ch;
         },
 
-        applyAITrackInstrument: function (bank, program) {
+        applyAITrackInstrument: function (bank, program, synthEngine) {
+            if (synthEngine) {
+                bank = bank !== undefined ? bank : (synthEngine.soundfont_bank || 0);
+                program = program !== undefined ? program : (synthEngine.soundfont_program || 0);
+            }
             const channel = this.allocateChannel(bank);
             this.controllerChange(channel, 0, bank);
             this.programChange(channel, program);
@@ -79,11 +83,20 @@
             return buffer;
         },
 
-        playNote: function (note, velocity, durationMs, startTime, program, destinationNode, channel) {
+        playNote: function (note, velocity, durationMs, startTime, program, destinationNode, channel, synthEngine) {
             const ctx = getCtx();
             const freq = 440 * Math.pow(2, (note - 69) / 12);
             if (freq <= 0 || isNaN(freq)) return null;
 
+            // Apply synth_engine state if provided
+            if (synthEngine) {
+                const ch = channel !== undefined ? channel : (synthEngine.soundfont_bank === 128 ? 9 : 0);
+                this.controllerChange(ch, 0, synthEngine.soundfont_bank || 0);
+                this.programChange(ch, synthEngine.soundfont_program || 0);
+                if (channel === undefined) channel = ch;
+                if (program === undefined) program = synthEngine.soundfont_program;
+            }
+
             const osc = ctx.createOscillator();
             const noteGain = ctx.createGain();
 

wiki.md

@@ -1,3 +1,9 @@
+### [2026-07-26 16:45] Task: Implement VST3/SoundFont engine plan
+- **Tóm tắt thay đổi:** Fix SF2 path resolution (hardcoded → multi-dir scan), add `synth_engine` struct parsing in render & UI, 3-level fallback chain, pass context to client SoundFont player.
+- **Các file ảnh hưởng:** `app/core/render_engine.py`, `app/static/js/app.jsx`, `app/static/js/services/soundfontPlayer.js`, `app/static/js/services/aiGateway.js`
+- **Ghi chú/Test (nếu có):** Verified: catalog API returns 31 condensed instruments, render with flat fields + synth_engine struct + drums (bank=128) + missing SF fallback all succeed.
+---
+
 ### [2026-07-25 06:57] Task: Fix Piano Roll runtime errors (rollBeats TDZ + handleCCMouseMove)
 - **Tóm tắt thay đổi:** Sửa lỗi `Cannot access 'rollBeats' before initialization` bằng cách di chuyển khai báo `rollBeats`/`rollBeatsRef` lên trước `totalBeats`. Thêm hàm `handleCCMouseMove` bị thiếu và cập nhật `handleCCMouseDown` hỗ trợ Ctrl+Click paint velocity.
 - **Các file ảnh hưởng:** `app/static/js/app.jsx`, `app/static/js/app.precompiled.js`