"""Score and sound effects for 'View Source', written in code. Music: 120 BPM in A minor (Am F C G), a bar every 2 s, so every cut in the film lands on a beat. Near silence while the page is inspected, a drop when the camera dives into the letters (10 s), a build into the guide page (54-58 s), a breakdown for "made from one message" (66 s) and one last chord (69.5 s). Effects: every effect has a cause on screen; the times below are copied from the scene files (compositions/*.html), in film seconds. usage: .venv/bin/python -I tools/make_music.py writes assets/audio/music.mp3 and assets/audio/sfx.mp3 """ import subprocess, sys from pathlib import Path import numpy as np from scipy.signal import butter, sosfilt SR = 44100 BPM = 120 BEAT = 60 / BPM # 0.5 s BAR = 4 * BEAT # 2 s LENGTH = 74.0 N = int(SR * LENGTH) rng = np.random.default_rng(42) NOTE = {n: i for i, n in enumerate(["C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B"])} def hz(name): n, o = name[:-1], int(name[-1]) return 440.0 * 2 ** ((NOTE[n] + 12 * (o + 1) - 69) / 12) CHORDS = { # bass root, chord tones (pad), arp tones "Am": ("A1", ["A3", "C4", "E4"], ["A4", "C5", "E5", "A5"]), "F": ("F1", ["F3", "A3", "C4"], ["F4", "A4", "C5", "F5"]), "C": ("C2", ["G3", "C4", "E4"], ["E4", "G4", "C5", "E5"]), "G": ("G1", ["G3", "B3", "D4"], ["D4", "G4", "B4", "D5"]), } PROG = ["Am", "F", "C", "G"] def chord_at(t): return PROG[int(t // BAR) % 4] # ---------- helpers ---------- def sos(kind, f, order=2): return butter(order, f, btype=kind, fs=SR, output="sos") def env(n, a, d, sustain=0.0, curve=4.0): """attack seconds, decay seconds (exponential)""" t = np.arange(n) / SR e = np.where(t < a, t / max(a, 1e-6), sustain + (1 - sustain) * np.exp(-(t - a) * curve / max(d, 1e-6))) return e def place(buf, sig, t, gain=1.0): i = int(round(t * SR)) if i >= len(buf): return j = min(len(buf), i + len(sig)) buf[i:j] += sig[: j - i] * gain def saw(f, n, detune=0.0): t = np.arange(n) / SR out = np.zeros(n) for d in (-detune, 0.0, detune): ph = (t * f * (1 + d)) % 1.0 out += 2 * ph - 1 return out / 3 def sine(f, n): return np.sin(2 * np.pi * f * np.arange(n) / SR) def noise(n): return rng.uniform(-1, 1, n) # ---------- instruments ---------- def kick(): n = int(0.38 * SR); t = np.arange(n) / SR f = 45 + 95 * np.exp(-t * 28) body = np.sin(2 * np.pi * np.cumsum(f) / SR) * np.exp(-t * 9) click = sosfilt(sos("highpass", 1500), noise(n)) * np.exp(-t * 300) * 0.4 return np.tanh(1.6 * (body + click)) def clap(): n = int(0.22 * SR); t = np.arange(n) / SR nz = sosfilt(sos("bandpass", [900, 4000]), noise(n)) e = np.exp(-t * 22) for off in (0.0, 0.011, 0.022): # three hands k = int(off * SR); e[k:k + 60] += 0.6 return nz * e * 0.9 + sine(190, n) * np.exp(-t * 40) * 0.3 def hat(open_=False): n = int((0.16 if open_ else 0.045) * SR); t = np.arange(n) / SR return sosfilt(sos("highpass", 7000), noise(n)) * np.exp(-t * (18 if open_ else 90)) def bass_note(f, dur): n = int(dur * SR) s = saw(f, n, 0.004) * 0.7 + sine(f, n) * 0.6 s = sosfilt(sos("lowpass", 420), s) return s * env(n, 0.005, dur * 0.9, 0.3, 3) def pad_chord(notes, dur, cutoff=1400): n = int(dur * SR) s = sum(saw(hz(x), n, 0.006) for x in notes) / len(notes) s = sosfilt(sos("lowpass", cutoff), s) a = min(0.4, dur / 3) t = np.arange(n) / SR e = np.clip(t / a, 0, 1) * np.clip((dur - t) / 0.25, 0, 1) return s * e def pluck(f, dur=0.32, bright=3200): n = int(dur * SR); t = np.arange(n) / SR s = saw(f, n, 0.002) * 0.6 + np.sign(sine(f, n)) * 0.25 s = sosfilt(sos("lowpass", bright), s) return s * np.exp(-t * 11) def lead(f, dur): n = int(dur * SR); t = np.arange(n) / SR vib = 1 + 0.004 * np.sin(2 * np.pi * 5.5 * t) ph = np.cumsum(f * vib) / SR s = (2 * (ph % 1) - 1) * 0.5 + np.sign(np.sin(2 * np.pi * ph)) * 0.3 s = sosfilt(sos("lowpass", 2600), s) return s * env(n, 0.01, dur, 0.55, 2) * np.clip((dur - t) / 0.06, 0, 1) def riser(dur): n = int(dur * SR); t = np.arange(n) / SR out = np.zeros(n) nz = noise(n) # sweep a band of noise upwards in slices slices = 40 for k in range(slices): a, b = k * n // slices, (k + 1) * n // slices fc = 300 * (1 + 25 * (k / slices) ** 2) out[a:b] = sosfilt(sos("bandpass", [fc * 0.7, min(fc * 1.4, 18000)]), nz[a:b]) tone = np.sin(2 * np.pi * np.cumsum(220 * 2 ** (2 * t / dur)) / SR) * 0.25 return (out * 0.8 + tone) * (t / dur) ** 2 def impact(): n = int(2.2 * SR); t = np.arange(n) / SR boom = np.sin(2 * np.pi * np.cumsum(40 + 60 * np.exp(-t * 6)) / SR) * np.exp(-t * 2.2) crash = sosfilt(sos("highpass", 3000), noise(n)) * np.exp(-t * 3.5) * 0.35 return np.tanh(1.3 * boom) + crash # ---------- the arrangement ---------- def music(): m = np.zeros(N + SR * 3) drums = np.zeros_like(m) K, CL, HC, HO = kick(), clap(), hat(), hat(True) def section(t0, t1, kick_on=True, clap_on=True, hats="8", bass=True, arp=True, pad=0.5, lead_on=False, cutoff=1400): b = t0 while b < t1 - 1e-6: ch = chord_at(b) root, padn, arpn = CHORDS[ch] bar_end = min(b + BAR, t1) if pad: place(m, pad_chord(padn, bar_end - b, cutoff), b, 0.22 * pad) for s in range(16): # sixteenths ts = b + s * BEAT / 4 if ts >= t1 - 1e-6: break if s % 4 == 0 and kick_on: place(drums, K, ts, 0.9) if s in (4, 12) and clap_on: place(drums, CL, ts, 0.5) if hats == "8" and s % 4 == 2: place(drums, HO, ts, 0.18) if hats == "16" and s % 2 == 1: place(drums, HC, ts, 0.22 if s % 4 == 3 else 0.12) if hats == "16" and s % 4 == 2: place(drums, HO, ts, 0.16) if bass and s % 2 == 1: place(m, bass_note(hz(root) * (2 if s % 4 == 3 else 1), BEAT / 2.2), ts, 0.42) if arp: place(m, pluck(hz(arpn[(s * 3) % 4])), ts, 0.11 if s % 4 else 0.15) if lead_on: # a four-note hook per bar, A minor pentatonic hook = {"Am": ["E5", "G5", "A5", "C6"], "F": ["C6", "A5", "G5", "E5"], "C": ["E5", "G5", "C6", "D6"], "G": ["D6", "B5", "G5", "D5"]}[ch] for i, nme in enumerate(hook): tt = b + [0, 0.75, 1.0, 1.5][i] * BEAT * 2 / 2 place(m, lead(hz(nme), 0.42), tt, 0.13) b += BAR # 0-10: the page is inspected: a quiet pad, a soft pulse from 4 s, a riser into the dive section(0, 10, kick_on=False, clap_on=False, hats=None, bass=False, arp=False, pad=0.55, cutoff=700) for k in range(int(4 / BEAT), int(10 / BEAT)): place(m, sine(hz("A1"), int(0.25 * SR)) * np.exp(-np.arange(int(0.25 * SR)) / SR * 14), k * BEAT, 0.25) place(m, riser(2.0), 8.0, 0.45) place(m, impact(), 10.0, 0.75) # 10-22 the five films section(10, 22, hats="8", pad=0.5) # 22-34 the conversation: lighter, no clap for the first bar of each message section(22, 34, clap_on=True, hats="8", pad=0.35, arp=True) # 34-50 the eleven steps: driving section(34, 50, hats="16", pad=0.45) # 50-58 the render: build, snare roll, riser section(50, 54, hats="16", pad=0.3, cutoff=900) section(54, 58, kick_on=True, clap_on=False, hats="16", pad=0.3, cutoff=2400) roll_t = 54.0 while roll_t < 58.0: step = BEAT / 2 if roll_t < 56 else (BEAT / 4 if roll_t < 57 else BEAT / 8) place(drums, CL, roll_t, 0.18 + 0.3 * (roll_t - 54) / 4) roll_t += step place(m, riser(4.0), 54.0, 0.5) place(m, impact(), 58.0, 0.8) # 58-66 the guide and "Your turn.": everything, with the hook section(58, 66, hats="16", pad=0.55, lead_on=True, cutoff=2000) # 66-69.5 "made from one message": breakdown, no drums section(66, 69.5, kick_on=False, clap_on=False, hats=None, bass=False, arp=True, pad=0.7, cutoff=1100) # 69.5 the end card: one last chord, ringing out place(m, impact(), 69.5, 0.55) end = pad_chord(["A2", "E3", "A3", "C4", "E4"], 4.5, 1600) place(m, end, 69.5, 0.35) place(m, bass_note(hz("A1"), 2.0), 69.5, 0.6) for i, nme in enumerate(["A4", "C5", "E5", "A5"]): place(m, pluck(hz(nme), 1.6, 2600), 69.5 + i * 0.06, 0.16) # sidechain: duck the music under each kick duck = np.ones_like(m) for k in range(int(LENGTH / BEAT)): t = k * BEAT if 10 <= t < 66: i = int(t * SR); L = int(0.18 * SR) duck[i:i + L] = np.minimum(duck[i:i + L], 0.55 + 0.45 * np.linspace(0, 1, L) ** 0.7) mix = m * duck + drums mix = mix[:N] # fade out at the very end fade = int(1.5 * SR) mix[-fade:] *= np.linspace(1, 0, fade) ** 1.5 return mix # ---------- effects ---------- def mouse_click(): n = int(0.03 * SR); t = np.arange(n) / SR a = sosfilt(sos("bandpass", [1800, 6000]), noise(n)) * np.exp(-t * 600) b = np.zeros(n); k = int(0.012 * SR) b[k:] = (sosfilt(sos("bandpass", [2500, 8000]), noise(n - k)) * np.exp(-np.arange(n - k) / SR * 900)) * 0.6 return (a + b) * 0.9 def key_tick(seed): r = np.random.default_rng(seed) n = int(0.03 * SR); t = np.arange(n) / SR s = sosfilt(sos("bandpass", [1500 + 800 * r.random(), 7000]), r.uniform(-1, 1, n)) * np.exp(-t * (350 + 150 * r.random())) return s + sine(220 + 60 * r.random(), n) * np.exp(-t * 120) * 0.25 def pop(f0=620): n = int(0.09 * SR); t = np.arange(n) / SR return np.sin(2 * np.pi * np.cumsum(f0 * np.exp(-t * 12)) / SR) * np.exp(-t * 40) def whoosh(dur=0.4, seed=0, up=True): r = np.random.default_rng(seed) n = int(dur * SR); t = np.arange(n) / SR nz = r.uniform(-1, 1, n); out = np.zeros(n) slices = 24 for k in range(slices): a, b = k * n // slices, (k + 1) * n // slices x = k / slices if up else 1 - k / slices fc = 400 + 4000 * x out[a:b] = sosfilt(sos("bandpass", [fc * 0.6, fc * 1.6]), nz[a:b]) e = np.sin(np.pi * t / dur) ** 2 return out * e def clack(seed): r = np.random.default_rng(seed) n = int(0.16 * SR); t = np.arange(n) / SR thump = np.sin(2 * np.pi * np.cumsum(140 * np.exp(-t * 20) + 60) / SR) * np.exp(-t * 35) s = thump * 0.8 for off in (0.0, 0.028, 0.05): # the claw, the gate, the shutter k = int(off * SR) L = int(0.02 * SR) s[k:k + L] += sosfilt(sos("bandpass", [1200, 5000]), r.uniform(-1, 1, L)) * np.exp(-np.arange(L) / SR * 400) * (0.9 - off * 6) return s def shutter(seed): r = np.random.default_rng(seed) n = int(0.06 * SR); s = np.zeros(n) for off in (0.0, 0.022): k = int(off * SR); L = int(0.015 * SR) s[k:k + L] += sosfilt(sos("bandpass", [2500, 9000]), r.uniform(-1, 1, L)) * np.exp(-np.arange(L) / SR * 500) return s def sfx(): s = np.zeros(N + SR) # s1 inspect for t in (2.6, 3.4, 4.9, 5.02, 8.0): place(s, mouse_click(), t, 0.7) for k in range(8): place(s, key_tick(k), 5.3 + k * 0.075, 0.45) place(s, key_tick(99), 6.0, 0.6) # Enter for k in range(16): # the value being pushed up place(s, key_tick(200 + k), 8.1 + k * 0.06, 0.18) place(s, whoosh(1.0, 3, True), 9.0, 0.35) # the dive # s2 films (+10) place(s, whoosh(0.35, 4), 11.85, 0.5) # whip place(s, whoosh(0.3, 5), 15.9, 0.3) # iris place(s, whoosh(0.35, 6, False), 17.85, 0.5) # push up # s3 talk (+22) for t in (22.05, 26.5, 30.35): place(s, pop(560), t, 0.35) # message sent for t in (22.9, 27.3, 31.1): place(s, pop(820), t, 0.25) # Claude answers for k in range(1, 19): # the slot reel place(s, key_tick(300 + k), 22 + 1.3 + 1.6 * (k / 18) ** 1.6, 0.3) place(s, pop(700), 25.1, 0.35) for k in range(10): place(s, key_tick(400 + k), 31.4 + k * 0.12, 0.18) place(s, whoosh(0.7, 7, True), 33.2, 0.45) # the bubble swallows the frame # s4 steps (+34): a projector clack per pull-down for i in range(11): place(s, clack(500 + i), 34.0 + i * 1.5, 0.55) place(s, whoosh(0.38, 8), 50.1, 0.45) # s5 render (+50.5): a shutter per still, then the flipbook for k in range(1, 31): place(s, shutter(600 + k), 50.5 + 0.6 + 4.7 * (k / 30) ** 0.55, 0.45) for k in range(30): place(s, key_tick(700 + k), 50.5 + 5.45 + k * 0.045, 0.14) place(s, pop(500), 56.72, 0.4) # s6 your turn (+58) for t in (59.95, 61.5): place(s, mouse_click(), t, 0.7) place(s, whoosh(0.7, 9, True), 62.4, 0.45) place(s, pop(640), 67.62, 0.3) return s[:N] def normalise(x, peak_db=-1.5): return x / (np.max(np.abs(x)) + 1e-9) * 10 ** (peak_db / 20) def write(x, path): wav = path.with_suffix(".wav") st = np.stack([x, x], axis=1) pcm = (np.clip(st, -1, 1) * 32767).astype(" 1 else ".") out = root / "assets" / "audio" out.mkdir(parents=True, exist_ok=True) m = normalise(np.tanh(music() * 1.2), -1.5) write(m * 0.75, out / "music.mp3") write(normalise(sfx(), -1.5) * 0.8, out / "sfx.mp3") print("wrote", out / "music.mp3", out / "sfx.mp3")