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| 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].system_reset() | |
| device[0].get_samples(self.sample_rate*5) # wait for silence | |
| 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 | |