Files
music-video-gen/flow-state/tools/build-song-bank.js
T
Dejvino 4d05250294 Clickable previews: exact app deep-links everywhere
Every rendered still links to the app frame that produced it (song + seed + frame + venue/viz pins + probe warm-up, new window), via shared src/ui/preview.js. Supporting work, each measured: app honors ?frame/?venueSel/?viz/?warm= with pre-build pins (Show.applyPins) and primes deep-link loads; shared pinViz/pinVenueShell paths for gallery, filmstrip and app; probes prime and carry their warm-up; bank probes analyse the bank PCM and file decode is fixed-rate with bit-exact WAV parsing so app and probes see identical samples; materials built mid-update compile synchronously (needsCompile). Round trip verified bit-identical gallery-versus-app.
2026-09-20 18:42:53 +02:00

255 lines
12 KiB
JavaScript
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
// Build the test song bank: synthesize every song in src/audio/songbank.js,
// write it out as audio, and verify that the bank covers what it claims to.
//
// The bank is generated rather than stored. It is deterministic, it is a few
// hundred megabytes as audio, and it is derived from a table that will keep
// changing — all three say "rebuild it" rather than "commit it". The output
// directory is gitignored; this tool is the thing that is versioned.
//
// node tools/build-song-bank.js → test/songs/, 120s each
// node tools/build-song-bank.js --duration 60 → shorter, for a quick pass
// node tools/build-song-bank.js --check → verify coverage, write nothing
// node tools/build-song-bank.js --out /tmp/bank
//
// Coverage is measured, never assumed. Each song declares the corner of the
// feature space it exists to occupy; this analyses what was actually produced
// and fails loudly if an axis has collapsed — a synth change that quietly stops
// producing noisy tracks would otherwise leave every downstream measurement
// looking fine while testing half the space.
import { writeFileSync, mkdirSync, existsSync } from 'node:fs';
import { resolve, dirname } from 'node:path';
import { fileURLToPath } from 'node:url';
import { synthesizeSong } from '../src/audio/synth.js';
import { FeatureTrack } from '../src/audio/FeatureTrack.js';
import { SONGS, AXES, bankPcm } from '../src/audio/songbank.js';
const here = dirname(fileURLToPath(import.meta.url));
function arg(name, fallback = null) {
const i = process.argv.indexOf(`--${name}`);
return i >= 0 && process.argv[i + 1] && !process.argv[i + 1].startsWith('--')
? process.argv[i + 1] : fallback;
}
const has = (name) => process.argv.includes(`--${name}`);
const DURATION = Number(arg('duration', 120));
const OUT = resolve(arg('out', resolve(here, '../test/songs')));
const CHECK_ONLY = has('check');
/**
* 16-bit PCM WAV, mono.
*
* Mono halves the size and loses nothing: the analyser sums to mono before it
* does anything, the synth writes the same signal to both channels anyway —
* and the probes analyse the mono bank PCM, so the files must be mono for
* app and probe features to match bit-exactly. See songbank.js bankPcm.
*/
function wav(samples, sampleRate) {
const bytes = samples.length * 2;
const buffer = Buffer.alloc(44 + bytes);
buffer.write('RIFF', 0);
buffer.writeUInt32LE(36 + bytes, 4);
buffer.write('WAVE', 8);
buffer.write('fmt ', 12);
buffer.writeUInt32LE(16, 16); // PCM chunk size
buffer.writeUInt16LE(1, 20); // PCM
buffer.writeUInt16LE(1, 22); // mono
buffer.writeUInt32LE(sampleRate, 24);
buffer.writeUInt32LE(sampleRate * 2, 28);
buffer.writeUInt16LE(2, 32); // block align
buffer.writeUInt16LE(16, 34); // bits
buffer.write('data', 36);
buffer.writeUInt32LE(bytes, 40);
// Peak-normalise to -1 dBFS. Without it the quiet ambient entries clip down
// into 16-bit noise and their measured flatness stops being what the spec
// asked for — the bank would then be testing the encoder, not the generator.
// Shared with songbank.js bankPcm: the files must hold exactly what the
// probes analyse, or app-vs-probe previews can never match.
const pcm = bankPcm(samples);
for (let i = 0; i < pcm.length; i++) {
buffer.writeInt16LE(Math.round(pcm[i] * 32768), 44 + i * 2);
}
return buffer;
}
if (!CHECK_ONLY && !existsSync(OUT)) mkdirSync(OUT, { recursive: true });
console.log(`\nbuilding ${SONGS.length} songs · ${DURATION}s each` +
(CHECK_ONLY ? ' · check only, writing nothing' : ` · → ${OUT}`) + '\n');
const built = [];
for (const spec of SONGS) {
const buffer = synthesizeSong({
bpm: spec.bpm,
duration: DURATION,
arrangement: spec.arrangement,
brightness: spec.brightness,
noise: spec.noise,
noiseColour: spec.noiseColour ?? null,
dynamics: spec.dynamics,
transition: spec.transition ?? 0.5,
seed: 1 + SONGS.indexOf(spec),
});
// Measured from the bank PCM — the same samples the files hold and the
// probes analyse (see songbank.js bankPcm) — not the raw synth.
const pcm = bankPcm(buffer.getChannelData(0));
const track = FeatureTrack.fromAudioBuffer({
sampleRate: buffer.sampleRate,
length: pcm.length,
duration: buffer.duration,
numberOfChannels: 1,
getChannelData: (i) => {
if (i !== 0) throw new Error('bank is mono');
return pcm;
},
}, { fps: 60 });
if (!CHECK_ONLY) {
writeFileSync(resolve(OUT, `${spec.name}.wav`),
wav(buffer.getChannelData(0), buffer.sampleRate));
}
built.push({
...spec,
file: `${spec.name}.wav`,
measured: {
bpm: track.summary.bpm,
centroid: track.summary.meanCentroid,
flatness: track.summary.meanFlatness,
dynamics: track.summary.dynamicRange,
loudness: track.summary.meanLoudness,
sections: track.sections.length,
kinds: track.sections.map((s) => s.kind),
},
});
process.stdout.write(` ${spec.name.padEnd(10)} ${built.at(-1).measured.kinds.join(' ')}\n`);
}
// --- what was actually produced -------------------------------------------
const n2 = (x) => (typeof x === 'number' ? x.toFixed(2) : String(x)).padStart(7);
console.log('\n MEASURED — what the generator will actually read\n');
console.log(' song tempo bright noisy dynamic loud sections arrangement cuts');
console.log(' ' + '-'.repeat(86));
for (const b of built) {
console.log(` ${b.name.padEnd(11)}${n2(b.measured.bpm)}${n2(b.measured.centroid)}` +
`${n2(b.measured.flatness)}${n2(b.measured.dynamics)}${n2(b.measured.loudness)}` +
`${String(b.measured.sections).padStart(10)} ${b.arrangement.padEnd(9)}` +
` ${(b.transition ?? 0.5) >= 0.7 ? 'hard' : (b.transition ?? 0.5) <= 0.3 ? 'soft' : 'mid '}`);
}
// --- coverage --------------------------------------------------------------
// An axis is covered when the bank spreads across it AND reaches both ends. A
// bank can have a wide range and still be two clusters with a hole in the
// middle, so occupancy is measured in quintiles rather than as min-to-max.
console.log('\n COVERAGE — measured, not claimed\n');
const problems = [];
for (const axis of AXES) {
const values = built.map((b) => b.measured[axis.key === 'bpm' ? 'bpm' : axis.key]);
const lo = Math.min(...values), hi = Math.max(...values);
const [rLo, rHi] = axis.range;
const bins = new Set(values.map(
(v) => Math.max(0, Math.min(4, Math.floor((v - rLo) / (rHi - rLo) * 5)))));
const filled = [0, 1, 2, 3, 4].map((i) => (bins.has(i) ? '█' : '·')).join('');
const span = (hi - lo) / (rHi - rLo);
console.log(` ${axis.label.padEnd(15)} ${filled} ${lo.toFixed(2)} → ${hi.toFixed(2)}` +
` spans ${(span * 100).toFixed(0)}% of ${rLo}–${rHi}`);
console.log(` ${''.padEnd(15)} reads: ${axis.reads}`);
if (bins.size < 3) problems.push(`${axis.label} occupies only ${bins.size}/5 of its range`);
}
// --- what the bank CANNOT decouple ----------------------------------------
// Spread on every axis is not the same as covering the space. Two axes that
// move together mean whole combinations are unrepresentable, and a downstream
// test would then attribute to the generator what is really a hole in the bank.
//
// One correlation here is a property of the ANALYSER and cannot be engineered
// away. Flatness is the geometric mean of the spectrum over its arithmetic
// mean, taken across the whole band, so a signal only measures flat if it has
// energy everywhere — which is the same thing as measuring bright. Adding a
// noise bed raises both, and band-limiting it to keep the centroid down empties
// the top of the spectrum and drops the flatness with it. Two attempts at
// decoupling (a steeper noise filter, then noise colour as its own axis) moved
// r from 0.95 to 0.94. Real material behaves the same way.
//
// So it is allowlisted with its reason rather than failed on, and anything NOT
// on the list still fails — the check is here to catch a bank that has
// collapsed, not to relitigate physics on every run.
console.log('\n AXIS CORRELATION — |r| near 1 means the bank cannot vary these independently\n');
const corr = (a, b) => {
const ma = a.reduce((x, y) => x + y, 0) / a.length;
const mb = b.reduce((x, y) => x + y, 0) / b.length;
let num = 0, da = 0, db = 0;
for (let i = 0; i < a.length; i++) {
num += (a[i] - ma) * (b[i] - mb);
da += (a[i] - ma) ** 2;
db += (b[i] - mb) ** 2;
}
return num / (Math.sqrt(da * db) || 1e-9);
};
const series = Object.fromEntries(AXES.map(
(a) => [a.key, built.map((b) => b.measured[a.key])]));
const EXPECTED = {
'brightness↔noisiness':
'spectral flatness is measured across the whole band, so flat implies bright',
};
for (let i = 0; i < AXES.length; i++) {
for (let j = i + 1; j < AXES.length; j++) {
const r = corr(series[AXES[i].key], series[AXES[j].key]);
if (Math.abs(r) < 0.6) continue;
const key = `${AXES[i].label}↔${AXES[j].label}`;
const expected = EXPECTED[key];
console.log(` ${AXES[i].label} ↔ ${AXES[j].label}: r = ${r.toFixed(2)}` +
(expected ? ` expected — ${expected}` : Math.abs(r) > 0.85 ? ' ← effectively one axis' : ''));
if (Math.abs(r) > 0.85 && !expected) {
problems.push(`${AXES[i].label} and ${AXES[j].label} are collinear (r ${r.toFixed(2)})`);
}
}
}
// Transition hardness is a spec input rather than a summary statistic, so it is
// reported rather than binned: how abruptly one section becomes the next is a
// genre difference the bank has to contain — an ambient record dissolves where a
// club record cuts — and a bank where every song cut would be testing the
// generator against one kind of music.
const soft = built.filter((b) => (b.transition ?? 0.5) <= 0.3).length;
const hard = built.filter((b) => (b.transition ?? 0.5) >= 0.7).length;
console.log(`\n transitions ${soft} soft · ${built.length - soft - hard} mid · ${hard} hard`);
if (!soft || !hard) problems.push('the bank has no ' + (soft ? 'hard' : 'soft') + ' transitions');
// Section kinds are the casting gate, so coverage of them is not optional: a
// bank with no drop cannot reach the geometric, glitch or structural families
// no matter how widely its tempo spreads.
const kinds = new Map();
for (const b of built) for (const k of b.measured.kinds) kinds.set(k, (kinds.get(k) || 0) + 1);
const ALL_KINDS = ['intro', 'build', 'drop', 'sustain', 'breakdown', 'outro'];
console.log(`\n section kinds ${ALL_KINDS.map((k) => (kinds.get(k) ? '█' : '·')).join('')} ` +
ALL_KINDS.map((k) => `${k} ${kinds.get(k) || 0}`).join(' · '));
const missing = ALL_KINDS.filter((k) => !kinds.get(k));
if (missing.length) problems.push(`no song produces: ${missing.join(', ')}`);
if (!CHECK_ONLY) {
writeFileSync(resolve(OUT, 'manifest.json'), JSON.stringify({
built: new Date().toISOString(),
duration: DURATION,
songs: built,
}, null, 2));
}
console.log('');
if (problems.length) {
console.log(' GAPS');
for (const p of problems) console.log(` ${p}`);
console.log('');
process.exitCode = 1;
} else {
console.log(` all ${AXES.length} axes and all ${ALL_KINDS.length} section kinds covered`);
if (!CHECK_ONLY) console.log(` wrote ${built.length} wav files + manifest.json to ${OUT}`);
console.log('');
}