feat: vẽ nhanh MIDI note

app/core/render_engine.py

@@ -1,6 +1,7 @@
 import os
 import numpy as np
 import soundfile as sf
+import scipy.signal as signal
 from app.config import settings
 from app.core.vst_engine import (
     render_midi_events_to_audio,
@@ -11,7 +12,7 @@ from app.core.vst_engine import (
 
 if HAS_PEDALBOARD:
     try:
-        from pedalboard import Pedalboard, Gain
+        from pedalboard import Pedalboard, Gain, Chorus, Reverb
     except Exception:
         HAS_PEDALBOARD = False
 
@@ -222,6 +223,57 @@ class PythonRenderEngine:
             if mute:
                 continue
 
+            # Apply Track FX (Chorus or Reverb)
+            fx_type = track.get("fx_type")
+            if fx_type == "chorus":
+                if HAS_PEDALBOARD:
+                    try:
+                        board = Pedalboard([Chorus(rate_hz=1.5, depth=0.25)])
+                        track_buffer = board(track_buffer, sample_rate=self.sample_rate)
+                    except Exception as e:
+                        print(f"[RenderEngine] Pedalboard Chorus failed: {e}")
+                else:
+                    # Fallback chorus using simple LFO delay modulation in scipy/numpy
+                    try:
+                        # 1.5 Hz sine LFO, modulating delay time between 15ms and 25ms (average 20ms)
+                        lfo = 0.020 + 0.005 * np.sin(2 * np.pi * 1.5 * np.arange(total_samples) / self.sample_rate)
+                        dry = track_buffer * 0.6
+                        wet = np.zeros_like(track_buffer)
+                        for ch in range(2):
+                            indices = np.arange(total_samples) - (lfo * self.sample_rate)
+                            indices = np.clip(indices, 0, total_samples - 1).astype(np.int32)
+                            wet[ch, :] = track_buffer[ch, indices]
+                        track_buffer = dry + wet * 0.5
+                    except Exception as e:
+                        print(f"[RenderEngine] Fallback Chorus failed: {e}")
+            elif fx_type == "reverb":
+                if HAS_PEDALBOARD:
+                    try:
+                        board = Pedalboard([Reverb(room_size=0.5, wet_level=0.4, dry_level=0.6)])
+                        track_buffer = board(track_buffer, sample_rate=self.sample_rate)
+                    except Exception as e:
+                        print(f"[RenderEngine] Pedalboard Reverb failed: {e}")
+                else:
+                    # Fallback reverb using exponentially decaying noise room impulse response
+                    try:
+                        # Generate impulse response (decaying noise)
+                        len_ir = int(self.sample_rate * 2.0)
+                        t_ir = np.arange(len_ir) / self.sample_rate
+                        decay = np.exp(-t_ir / 0.5)
+                        ir_l = (np.random.rand(len_ir) * 2 - 1) * decay
+                        ir_r = (np.random.rand(len_ir) * 2 - 1) * decay
+                        
+                        dry = track_buffer * 0.6
+                        wet = np.zeros_like(track_buffer)
+                        for ch in range(2):
+                            ir = ir_l if ch == 0 else ir_r
+                            # Convolve
+                            conv = signal.convolve(track_buffer[ch, :], ir, mode='full')[:total_samples]
+                            wet[ch, :] = conv
+                        track_buffer = dry + wet * 0.4
+                    except Exception as e:
+                        print(f"[RenderEngine] Fallback Reverb failed: {e}")
+
             # Process track volume
             if HAS_PEDALBOARD:
                 try: