Upload midi_synthesizer.py

midi_synthesizer.py

@@ -0,0 +1,53 @@
+import fluidsynth
+import numpy as np
+
+
+def synthesis(midi_opus, soundfont_path, sample_rate=44100):
+    ticks_per_beat = midi_opus[0]
+    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)
+    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)
+
+    fl.delete()
+    if ss.shape[0] > 0:
+        max_val = np.abs(ss).max()
+        if max_val != 0:
+            ss = (ss / max_val) * np.iinfo(np.int16).max
+    ss = ss.astype(np.int16)
+    return ss