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Monorepo for Aesthetic.Computer aesthetic.computer
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Python
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153#!/usr/bin/env python3"""os_to_np.py — extract a melody from an Online Sequencer URL.
Online Sequencer encodes the song as a base64-protobuf blob inside theHTML page (`var data = '...'`). This script: 1. Fetches the HTML. 2. Pulls the data blob. 3. Parses the protobuf into per-instrument note lists. 4. With no --instrument, prints a summary of all instruments. 5. With --instrument N, emits a .np matching that voice.
Usage: os_to_np.py https://onlinesequencer.net/509647 out.np os_to_np.py https://onlinesequencer.net/509647 out.np --instrument 14 os_to_np.py https://onlinesequencer.net/509647 out.np \ --instrument 14 --start-time 8 --end-time 200 \ --lyrics "its a small world af- -ter all ...""""import argparse, base64, re, struct, sys, urllib.requestfrom collections import defaultdictfrom pathlib import Path
NOTE = ['C','C#','D','D#','E','F','F#','G','G#','A','A#','B']def note_name(p): return f"{NOTE[p%12]}{p//12-1}"
def read_varint(b, i): n = 0; shift = 0 while True: if i >= len(b): return None, i v = b[i]; i += 1 n |= (v & 0x7f) << shift if v < 0x80: return n, i shift += 7
def parse_msg(b, end): out = {}; i = 0 while i < end: tag, i = read_varint(b, i) if tag is None: break wire = tag & 7; fid = tag >> 3 if wire == 0: v, i = read_varint(b, i); out.setdefault(fid, []).append(v) elif wire == 5: if i + 4 > end: break v = struct.unpack('<f', b[i:i+4])[0]; i += 4 out.setdefault(fid, []).append(v) elif wire == 2: length, i = read_varint(b, i) if i + length > end: break out.setdefault(fid, []).append(b[i:i+length]); i += length elif wire == 1: if i + 8 > end: break i += 8 else: return out return out
def fetch_data(url): req = urllib.request.Request(url, headers={"User-Agent": "Mozilla/5.0"}) html = urllib.request.urlopen(req, timeout=30).read().decode("utf-8", errors="ignore") m = re.search(r"var data = '([^']+)'", html) if not m: raise RuntimeError("no `var data` blob found in page") blob = m.group(1) # Add padding for stray base64 if needed pad = len(blob) % 4 if pad: blob += "=" * (4 - pad) return base64.b64decode(blob, validate=False)
def main(): ap = argparse.ArgumentParser() ap.add_argument("url") ap.add_argument("out") ap.add_argument("--instrument", type=int, help="instrument id (run without to list)") ap.add_argument("--start-time", type=float, default=0, help="OS time units (16th-notes) — skip earlier notes") ap.add_argument("--end-time", type=float, default=1e12) ap.add_argument("--lyrics", help="whitespace-separated syllables") ap.add_argument("--bpm", type=int, default=120) ap.add_argument("--units-per-beat", type=int, default=4, help="OS time unit → beat divisor (default 4 = sixteenth-notes)") args = ap.parse_args()
blob = fetch_data(args.url) top = parse_msg(blob, len(blob)) by_instr = defaultdict(list) for n_raw in top.get(2, []): m = parse_msg(n_raw, len(n_raw)) p = m.get(1, [None])[0] s = m.get(2, [0.0])[0] l = m.get(3, [None])[0] instr = m.get(4, [None])[0] if p is not None: by_instr[instr].append((s, p, l))
if args.instrument is None: print(f"\n{args.url}\n{len(by_instr)} instruments\n") for instr in sorted(by_instr): notes = sorted(by_instr[instr]) ps = [n[1] for n in notes] lo, hi = min(ps), max(ps) med = sorted(ps)[len(ps)//2] first = notes[0] print(f" instr {instr:3d}: {len(notes):4d} notes range {note_name(lo)}-{note_name(hi)} median {note_name(med)} first {note_name(first[1])}@t={first[0]:.0f}") print("\npass --instrument N to extract that voice") return 0
notes = sorted(by_instr.get(args.instrument, [])) notes = [n for n in notes if args.start_time <= n[0] < args.end_time] if not notes: print(f"✗ no notes for instrument {args.instrument}", file=sys.stderr); return 1
# OS uses sixteenth-notes (units_per_beat=4). Convert each note's # length to .np beat weights by rounding to the nearest integer # ≥ 1. Inflate weights to absorb rests so the next syllable lands # at the right beat. upb = args.units_per_beat syls = [] for i, (s, p, l) in enumerate(notes): # Effective length = max(note length, gap until next note start) if i + 1 < len(notes): next_s = notes[i + 1][0] eff = next_s - s else: eff = l or 0 beats = max(1, round(eff / upb)) syls.append((p, beats))
toks = (args.lyrics.split() if args.lyrics else [f"n{i:02d}" for i in range(len(syls))]) if args.lyrics and len(toks) != len(syls): print(f"⚠ {len(toks)} lyric tokens vs {len(syls)} notes — using min({min(len(toks), len(syls))})", file=sys.stderr) n = min(len(toks), len(syls))
lines = [] lines.append(f"# Extracted by os_to_np.py from {args.url}") lines.append(f"# instrument {args.instrument} · {n} syllables · {args.bpm} bpm") if args.start_time or args.end_time < 1e12: lines.append(f"# window: t={args.start_time}-{args.end_time} (16th-notes)") lines.append("") lines.append("verse 1") line, cum = [], 0 for i in range(n): p, beats = syls[i] line.append(f"{note_name(p)}:{toks[i]}*{beats}") cum += beats if cum >= 12: lines.append(" ".join(line)); line, cum = [], 0 if line: lines.append(" ".join(line)) Path(args.out).write_text("\n".join(lines) + "\n") print(f"✓ {args.out} · {n} syllables · bpm {args.bpm}") return 0
if __name__ == "__main__": sys.exit(main())