Update midi_synthesizer.py

midi_synthesizer.py

@@ -4,51 +4,45 @@ import numpy as np
 
 def synthesis(midi_opus, soundfont_path, sample_rate=44100):
     ticks_per_beat = midi_opus[0]
-    tempo = int((60 / 140) * 10 ** 6)  # default 140 bpm
+    event_list = []
+    for track_idx, track in enumerate(midi_opus[1:]):
+        abs_t = 0
+        for event in track:
+            abs_t += event[1]
+            event_new = [*event]
+            event_new[1] = abs_t
+            event_list.append(event_new)
+    event_list = sorted(event_list, key=lambda e: e[1])
 
+    tempo = int((60 / 120) * 10 ** 6)  # default 120 bpm
+    ss = np.empty((0, 2), dtype=np.int16)
     fl = fluidsynth.Synth(samplerate=float(sample_rate))
     sfid = fl.sfload(soundfont_path)
-    waveforms = []
-    for track_idx, track in enumerate(midi_opus[1:]):
-        ss = np.empty((0, 2), dtype=np.int16)
-        cur_t = 0
-        last_t = 0
-        fl.system_reset()
-        fl.get_samples(int(2 * sample_rate))  # get 2 seconds sample to eliminate reverb sound from previous track
-        for c in range(16):
-            fl.program_select(c, sfid, 128 if c == 9 else 0, 0)
-        for event in track:
-            name = event[0]
-            cur_t += event[1]
-            sample_len = int(((cur_t / ticks_per_beat) * tempo / (10 ** 6)) * sample_rate)
-            sample_len -= int(((last_t / ticks_per_beat) * tempo / (10 ** 6)) * sample_rate)
-            last_t = cur_t
-            if sample_len > 0:
-                sample = fl.get_samples(sample_len).reshape(sample_len, 2)
-                ss = np.concatenate([ss, sample])
-            if name == "set_tempo":
-                tempo = event[2]
-            elif name == "patch_change":
-                c, p = event[2:4]
-                fl.program_select(c, sfid, 128 if c == 9 else 0, p)
-            elif name == "control_change":
-                c, cc, v = event[2:5]
-                fl.cc(c, cc, v)
-            elif name == "note_on" and event[3] > 0:
-                c, p, v = event[2:5]
-                fl.noteon(c, p, v)
-            elif name == "note_off" or (name == "note_on" and event[3] == 0):
-                c, p = event[2:4]
-                fl.noteoff(c, p)
-        waveforms.append(ss)
-    fl.delete()
-    synthesized = np.zeros((max([w.shape[0] for w in waveforms]), 2), dtype=np.int32)
-    for waveform in waveforms:
-        synthesized[:waveform.shape[0]] += waveform
-    if synthesized.shape[0] > 0:
-        max_val = np.abs(synthesized).max()
-        if max_val != 0:
-            synthesized = (synthesized / max_val) * np.iinfo(np.int16).max
-    synthesized = synthesized.astype(np.int16)
+    last_t = 0
+    for c in range(16):
+        fl.program_select(c, sfid, 128 if c == 9 else 0, 0)
+    for event in event_list:
+        name = event[0]
+        sample_len = int(((event[1] / ticks_per_beat) * tempo / (10 ** 6)) * sample_rate)
+        sample_len -= int(((last_t / ticks_per_beat) * tempo / (10 ** 6)) * sample_rate)
+        last_t = event[1]
+        if sample_len > 0:
+            sample = fl.get_samples(sample_len).reshape(sample_len, 2)
+            ss = np.concatenate([ss, sample])
+        if name == "set_tempo":
+            tempo = event[2]
+        elif name == "patch_change":
+            c, p = event[2:4]
+            fl.program_select(c, sfid, 128 if c == 9 else 0, p)
+        elif name == "control_change":
+            c, cc, v = event[2:5]
+            fl.cc(c, cc, v)
+        elif name == "note_on" and event[3] > 0:
+            c, p, v = event[2:5]
+            fl.noteon(c, p, v)
+        elif name == "note_off" or (name == "note_on" and event[3] == 0):
+            c, p = event[2:4]
+            fl.noteoff(c, p)
 
-    return synthesized
+    fl.delete()
+    return ss