import fluidsynth import numpy as np class MidiSynthesizer: def __init__(self, soundfont_path, sample_rate=44100): self.soundfont_path = soundfont_path self.sample_rate = sample_rate fl = fluidsynth.Synth(samplerate=float(sample_rate)) sfid = fl.sfload(soundfont_path) self.devices = [[fl, sfid, False]] def get_fluidsynth(self): for device in self.devices: if not device[2]: device[2] = True return device fl = fluidsynth.Synth(samplerate=float(self.sample_rate)) sfid = fl.sfload(self.soundfont_path) device = [fl, sfid, True] self.devices.append(device) return device def release_fluidsynth(self, device): device[0].get_samples(self.sample_rate*5) # wait for silence device[0].system_reset() device[2] = False def synthesis(self, midi_opus): 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) device = self.get_fluidsynth() fl, sfid = device[:-1] 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)) * self.sample_rate) sample_len -= int(((last_t / ticks_per_beat) * tempo / (10 ** 6)) * self.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) self.release_fluidsynth(device) 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