File size: 3,146 Bytes
b2e4883 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 | #!/usr/bin/env python3
"""
midjson_to_mid.py
=================
Consume the JSON event stream emitted by gp_to_keyswitched_mid.js and write
one Type-1 MIDI file per track into <out_dir>, named <TrackName>_keyswitched.mid.
Usage:
node gp_to_keyswitched_mid.js input.gp out_dir > events.json
python midjson_to_mid.py events.json <out_dir>
"""
import json
import os
import re
import sys
import mido
_FORBIDDEN = re.compile(r'[\\/:\*\?"<>\|]+')
_WS = re.compile(r'\s+')
def sanitize(name, default="output"):
cleaned = _FORBIDDEN.sub(' ', name or '')
cleaned = _WS.sub(' ', cleaned).strip().rstrip('. ')
return cleaned or default
def write_track(mid, name, channel, events, ticks_per_beat=960):
track = mid.add_track(name[:127] if name else "Guitar")
last = 0
for e in events:
tick = max(0, int(e['tick']))
kind = e['kind']
note = int(e['note'])
vel = int(e.get('velocity', 0))
if kind == 'note_on' and vel > 0:
msg = mido.Message('note_on', channel=channel, note=note,
velocity=max(1, min(127, vel)), time=tick - last)
else:
msg = mido.Message('note_off', channel=channel, note=note,
velocity=0, time=tick - last)
track.append(msg)
last = tick
return track
def main():
if len(sys.argv) < 3:
print("Usage: python midjson_to_mid.py <events.json> <out_dir>",
file=sys.stderr)
return 2
events_path = sys.argv[1]
out_dir = sys.argv[2]
with open(events_path, 'r', encoding='utf-8') as f:
data = json.load(f)
os.makedirs(out_dir, exist_ok=True)
tempo = int(data.get('tempo', 120))
ts = data.get('timeSignature', {})
ts_num = int(ts.get('numerator', 4))
ts_den = int(ts.get('denominator', 4))
written = []
for tr in data.get('tracks', []):
events = tr['events']
if not events:
continue
mid = mido.MidiFile(type=1, ticks_per_beat=960)
conductor = mid.add_track("Conductor")
conductor.append(mido.MetaMessage(
'set_tempo', tempo=mido.bpm2tempo(tempo), time=0))
conductor.append(mido.MetaMessage(
'time_signature', numerator=ts_num, denominator=ts_den, time=0))
write_track(mid, tr['name'], int(tr['channel']), events)
fname = sanitize(tr['name']) + "_keyswitched.mid"
out_path = os.path.join(out_dir, fname)
mid.save(out_path)
# stats
ks_notes = sum(1 for e in events if e['kind'] == 'note_on' and e.get('ks'))
played = sum(1 for e in events if e['kind'] == 'note_on' and not e.get('ks'))
written.append((out_path, tr['name'], tr['channel'], len(events), ks_notes, played))
for out_path, name, ch, nev, ks, played in written:
size = os.path.getsize(out_path)
print(f" {os.path.basename(out_path)} ({size:,}B, ch={ch}) "
f"events={nev} keyswitch_on={ks} played_notes={played}")
print(f"\nWrote {len(written)} file(s) to {out_dir}")
return 0
if __name__ == '__main__':
sys.exit(main()) |