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SubMiner/src/core/services/media-timing-waveform.test.ts
T

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TypeScript

import assert from 'node:assert/strict';
import test from 'node:test';
import {
buildSpeechWaveformArgs,
computeWaveformPeaks,
generateSpeechWaveform,
} from './media-timing-waveform';
function pcm(samples: number[]): Buffer {
const result = Buffer.alloc(samples.length * 2);
samples.forEach((sample, index) => result.writeInt16LE(sample, index * 2));
return result;
}
test('speech waveform maps the selected FFmpeg stream and visible range', () => {
const args = buildSpeechWaveformArgs(
{
mediaPath: '/video/show.mkv',
startTime: 8,
endTime: 15,
audioStreamIndex: 3,
},
'center',
);
assert.deepEqual(args.slice(args.indexOf('-ss'), args.indexOf('-t') + 2), [
'-ss',
'8',
'-i',
'/video/show.mkv',
'-t',
'7',
]);
assert.deepEqual(args.slice(args.indexOf('-map'), args.indexOf('-map') + 2), ['-map', '0:3']);
assert.match(args[args.indexOf('-af') + 1] ?? '', /c0=FC/);
});
test('speech waveform seeks cached windows by source timestamps', () => {
const args = buildSpeechWaveformArgs(
{
mediaPath: { path: '/tmp/window.mkv', absoluteTimestamps: true, singleResolvedStream: true },
startTime: 8,
endTime: 15,
},
'downmix',
);
assert.deepEqual(args.slice(args.indexOf('-ss'), args.indexOf('-t') + 2), [
'-ss',
'8',
'-seek_timestamp',
'1',
'-i',
'/tmp/window.mkv',
'-t',
'7',
]);
assert.equal(args.includes('-map'), false);
});
test('waveform levels rise with loudness and top out at the reference level', () => {
const peaks = computeWaveformPeaks(pcm([0, 1_000, -2_000, 4_000, -8_000, 16_000]), 3);
assert.equal(peaks.length, 3);
assert.equal(peaks[0], 0);
assert.ok((peaks[1] ?? 0) > 0);
assert.ok((peaks[1] ?? 0) < (peaks[2] ?? 0));
assert.equal(peaks[2], 1);
});
test('waveform flattens steady background noise and keeps speech bursts tall', () => {
// 20 slices of steady noise at a fixed level with an 18 dB louder "speech" burst in the middle.
const noise = 1_000;
const samples: number[] = [];
for (let slice = 0; slice < 20; slice += 1) {
const level = slice >= 8 && slice < 12 ? noise * 8 : noise;
for (let sample = 0; sample < 50; sample += 1) {
samples.push(sample % 2 === 0 ? level : -level);
}
}
const peaks = computeWaveformPeaks(pcm(samples), 20);
for (const [index, peak] of peaks.entries()) {
if (index >= 8 && index < 12) assert.equal(peak, 1);
else assert.equal(peak, 0);
}
});
test('waveform stays flat when the whole range is a single steady level', () => {
const peaks = computeWaveformPeaks(
pcm(Array.from({ length: 400 }, (_, i) => (i % 2 ? 900 : -900))),
40,
);
assert.ok(peaks.every((peak) => peak === 0));
});
test('speech waveform uses a mono downmix when the source has no center activity', async () => {
const calls: string[][] = [];
const peaks = await generateSpeechWaveform(
{ mediaPath: '/video/show.mkv', startTime: 0, endTime: 2 },
async (args) => {
calls.push(args);
return calls.length === 1 ? pcm([0, 0, 0, 0]) : pcm([0, 4_000, -8_000, 16_000]);
},
);
assert.equal(calls.length, 2);
assert.match(calls[1]?.[calls[1].indexOf('-af') + 1] ?? '', /channel_layouts=mono/);
assert.equal(Math.max(...peaks), 1);
});
test('speech waveform keeps an active center channel without doing a second decode', async () => {
let calls = 0;
await generateSpeechWaveform(
{ mediaPath: '/video/show.mkv', startTime: 0, endTime: 2 },
async () => {
calls += 1;
return pcm([0, 4_000, -8_000, 16_000]);
},
);
assert.equal(calls, 1);
});