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from threading import Lock
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import fluidsynth
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import numpy as np
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class MidiSynthesizer:
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def __init__(self, soundfont_path, sample_rate=44100):
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self.soundfont_path = soundfont_path
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self.sample_rate = sample_rate
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fl = fluidsynth.Synth(samplerate=float(sample_rate))
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sfid = fl.sfload(soundfont_path)
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self.devices = [[fl, sfid, False]]
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self.file_lock = Lock()
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def get_fluidsynth(self):
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for device in self.devices:
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if not device[2]:
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device[2] = True
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return device
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with self.file_lock:
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fl = fluidsynth.Synth(samplerate=float(self.sample_rate))
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sfid = fl.sfload(self.soundfont_path)
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device = [fl, sfid, True]
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self.devices.append(device)
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return device
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def release_fluidsynth(self, device):
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device[0].system_reset()
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device[0].get_samples(self.sample_rate*5)
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device[2] = False
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def synthesis(self, midi_opus):
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ticks_per_beat = midi_opus[0]
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event_list = []
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for track_idx, track in enumerate(midi_opus[1:]):
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abs_t = 0
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for event in track:
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abs_t += event[1]
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event_new = [*event]
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event_new[1] = abs_t
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event_list.append(event_new)
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event_list = sorted(event_list, key=lambda e: e[1])
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tempo = int((60 / 120) * 10 ** 6)
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ss = np.empty((0, 2), dtype=np.int16)
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device = self.get_fluidsynth()
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fl, sfid = device[:-1]
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last_t = 0
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for c in range(16):
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fl.program_select(c, sfid, 128 if c == 9 else 0, 0)
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for event in event_list:
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name = event[0]
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sample_len = int(((event[1] / ticks_per_beat) * tempo / (10 ** 6)) * self.sample_rate)
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sample_len -= int(((last_t / ticks_per_beat) * tempo / (10 ** 6)) * self.sample_rate)
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last_t = event[1]
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if sample_len > 0:
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sample = fl.get_samples(sample_len).reshape(sample_len, 2)
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ss = np.concatenate([ss, sample])
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if name == "set_tempo":
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tempo = event[2]
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elif name == "patch_change":
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c, p = event[2:4]
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fl.program_select(c, sfid, 128 if c == 9 else 0, p)
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elif name == "control_change":
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c, cc, v = event[2:5]
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fl.cc(c, cc, v)
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elif name == "note_on" and event[3] > 0:
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c, p, v = event[2:5]
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fl.noteon(c, p, v)
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elif name == "note_off" or (name == "note_on" and event[3] == 0):
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c, p = event[2:4]
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fl.noteoff(c, p)
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self.release_fluidsynth(device)
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if ss.shape[0] > 0:
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max_val = np.abs(ss).max()
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if max_val != 0:
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ss = (ss / max_val) * np.iinfo(np.int16).max
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ss = ss.astype(np.int16)
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return ss
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