"""Original score for 'From one island to another': a light stop-motion caper. Plucked ukulele (Karplus-Strong), pizzicato bass, glockenspiel and a soft shaker at 100 BPM in F, with the arrangement following the scene timeline (assets/timeline.json). Also writes assets/audio/animatic.mp3 = music + narration, for the storyboard page. usage: .venv/bin/python -I tools/make_music.py """ import json, subprocess, sys from pathlib import Path import numpy as np from scipy.signal import butter, sosfilt SR = 44100 BPM = 100 BEAT = 60 / BPM BAR = 4 * BEAT rng = np.random.default_rng(7) NOTE = {n: i for i, n in enumerate(["C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"])} def hz(name): # "F4", "A#3" n, o = name[:-1], int(name[-1]) return 440.0 * 2 ** ((NOTE[n] + 12 * (o + 1) - 69) / 12) CHORDS = { # ukulele voicings (G C E A tuning, re-entrant), bass root "F": (["A4", "C4", "F4", "A4"], "F2"), "Dm": (["A4", "D4", "F4", "A4"], "D2"), "Bb": (["A#4", "D4", "F4", "A#4"], "A#1"), "C": (["G4", "C4", "E4", "C5"], "C2"), "Gm": (["G4", "D4", "G4", "A#4"], "G1"), "A": (["A4", "C#4", "E4", "A4"], "A1"), "Am": (["A4", "C4", "E4", "A4"], "A1"), } TONES = {"F": ["F", "A", "C"], "Dm": ["D", "F", "A"], "Bb": ["A#", "D", "F"], "C": ["C", "E", "G"], "Gm": ["G", "A#", "D"], "A": ["A", "C#", "E"], "Am": ["A", "C", "E"]} # arrangement per scene: progression, layers, energy ARR = { "s1": dict(prog=["F", "F", "Dm", "C"], uke=0.6, bass=0.0, glock=0.8, shaker=0.0, pizz8=False), "s2": dict(prog=["F", "Dm", "Bb", "C"], uke=1.0, bass=1.0, glock=0.5, shaker=0.6, pizz8=False), "s3": dict(prog=["F", "Dm", "Bb", "C"], uke=1.0, bass=1.0, glock=0.7, shaker=0.8, pizz8=False), "s4": dict(prog=["Dm", "Bb", "Gm", "A"], uke=0.8, bass=1.0, glock=0.3, shaker=1.0, pizz8=True), "s5": dict(prog=["F", "Am", "Bb", "C"], uke=1.0, bass=1.0, glock=0.6, shaker=0.9, pizz8=False), "s6": dict(prog=["F", "Dm", "Bb", "C"], uke=1.0, bass=1.0, glock=0.9, shaker=0.9, pizz8=False), "s7": dict(prog=["Bb", "F", "Gm", "C"], uke=0.6, bass=0.7, glock=0.6, shaker=0.0, pizz8=False), "s8": dict(prog=["F", "Bb", "C", "F"], uke=1.0, bass=1.0, glock=1.0, shaker=1.0, pizz8=False), } def ks(freq, dur, decay=0.996, bright=0.5): """Karplus-Strong plucked string.""" n = int(SR * dur) period = max(2, int(SR / freq)) buf = rng.uniform(-1, 1, period) buf = np.convolve(buf, np.ones(3) / 3, mode="same") * (0.5 + bright) out = np.zeros(n) for i in range(n): out[i] = buf[i % period] buf[i % period] = decay * 0.5 * (buf[i % period] + buf[(i + 1) % period]) return out _ks_cache = {} def pluck(freq, dur, decay=0.996, bright=0.5): k = (round(freq, 2), dur, decay, bright) if k not in _ks_cache: _ks_cache[k] = ks(freq, dur, decay, bright) return _ks_cache[k] def bell(freq, dur): t = np.arange(int(SR * dur)) / SR s = (np.sin(2 * np.pi * freq * t) * np.exp(-t * 3.2) + 0.35 * np.sin(2 * np.pi * freq * 2.76 * t) * np.exp(-t * 7) + 0.15 * np.sin(2 * np.pi * freq * 5.4 * t) * np.exp(-t * 12)) s[: int(SR * 0.002)] *= np.linspace(0, 1, int(SR * 0.002)) return s def pizz(freq, dur=0.5): t = np.arange(int(SR * dur)) / SR f = freq * (1 + 0.02 * np.exp(-t * 40)) ph = 2 * np.pi * np.cumsum(f) / SR s = (np.sin(ph) + 0.3 * np.sin(2 * ph) + 0.1 * np.sin(3 * ph)) * np.exp(-t * 6) s[: 60] *= np.linspace(0, 1, 60) return s def shaker(dur=0.08): n = int(SR * dur) s = rng.uniform(-1, 1, n) * np.exp(-np.arange(n) / SR * 60) return sosfilt(butter(2, [5000, 11000], "bandpass", fs=SR, output="sos"), s) def add(buf, sig, t, gain, pan=0.0): i = int(t * SR) if i >= buf.shape[1]: return sig = sig[: buf.shape[1] - i] buf[0, i:i + len(sig)] += sig * gain * (1 - pan) * 0.5 * 2 ** 0.5 buf[1, i:i + len(sig)] += sig * gain * (1 + pan) * 0.5 * 2 ** 0.5 def main(): root = Path(sys.argv[1]) tl = json.loads((root / "assets/timeline.json").read_text()) total = tl["total"] scenes = tl["scenes"] buf = np.zeros((2, int(SR * (total + 3)))) scene_at = lambda t: next((s["id"] for s in reversed(scenes) if s["start"] <= t + 1e-3), "s1") nbars = int(np.ceil(total / BAR)) for b in range(nbars): t0 = b * BAR sid = scene_at(t0 + 0.05) a = ARR[sid] # bar index within the scene's progression first = int(np.ceil(next(s["start"] for s in scenes if s["id"] == sid) / BAR - 1e-6)) chord = a["prog"][(b - first) % 4] voicing, root_note = CHORDS[chord] last_bar = b == nbars - 1 # ukulele: off-beat "chunk" strums + down strum on 1 if a["uke"]: for beat in range(4): for half, g in ((0, 0.55), (0.5, 0.85)): if beat == 0 and half == 0: g = 0.9 tt = t0 + (beat + half) * BEAT for k, note in enumerate(voicing): add(buf, pluck(hz(note), 0.9, 0.993, 0.4), tt + k * 0.011, 0.07 * g * a["uke"], pan=-0.25) # pizzicato bass on 1 and 3 (8ths in the chaos scene) if a["bass"]: r = hz(root_note) hits = [(0, r), (2, r * 1.5)] if not a["pizz8"] else [(i * 0.5, r * (1.5 if i % 4 == 2 else 1)) for i in range(8)] for beat, f in hits: add(buf, pizz(f, 0.6), t0 + beat * BEAT, 0.28 * a["bass"], pan=0.1) # shaker 8ths with a little swing if a["shaker"]: for i in range(8): tt = t0 + (i * 0.5 + (0.06 if i % 2 else 0)) * BEAT add(buf, shaker(), tt, (0.05 if i % 2 else 0.03) * a["shaker"], pan=0.35) # glockenspiel: a few chord tones high up, more on bar 1 of 4 if a["glock"]: tones = TONES[chord] pattern = [0, 1.5, 2, 3] if (b - first) % 2 == 0 else [0.5, 2.5] for i, beat in enumerate(pattern): n = tones[(b + i * 2) % 3] + ("6" if i % 3 == 2 else "5") add(buf, bell(hz(n), 1.4), t0 + beat * BEAT, 0.09 * a["glock"], pan=0.3) if last_bar: pass # final chord ring-out on F, timed to the last line's end end = scenes[-1]["voiceAt"] + scenes[-1]["voiceDur"] + 0.2 for k, note in enumerate(["F3", "A3", "C4", "F4", "A4"]): add(buf, pluck(hz(note), 3.0, 0.9985, 0.5), end + k * 0.03, 0.1) for note in ["F5", "A5", "C6"]: add(buf, bell(hz(note), 3.0), end + 0.05, 0.08) add(buf, pizz(hz("F1"), 1.5), end, 0.35) # fades: gentle in, out at the end n_end = int(SR * (total + 1.0)) buf = buf[:, :n_end] fade = np.ones(n_end) fi = int(SR * 0.8); fade[:fi] = np.linspace(0, 1, fi) fo = int(SR * 2.0); fade[-fo:] = np.linspace(1, 0, fo) buf *= fade buf /= max(1e-6, np.abs(buf).max()) / 0.89 out = root / "assets/music"; out.mkdir(parents=True, exist_ok=True) wav = out / "score.wav" import wave with wave.open(str(wav), "wb") as w: w.setnchannels(2); w.setsampwidth(2); w.setframerate(SR) w.writeframes((buf.T * 32767).astype("", out / "score.mp3", "| animatic ->", aud / "animatic.mp3") main()