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AudioCapture: adaptive chunks (8s max, flush after 1s silence)

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Made-with: Cursor
This commit is contained in:
ValueOn AG 2026-02-28 00:49:11 +01:00
parent 07f7b03515
commit 25f684eb58
1 changed files with 32 additions and 8 deletions
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40
src/bot/audioCaptureProcedure.ts
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@ -124,18 +124,20 @@ export class AudioCaptureProcedure {
let callbackCount = 0;
let totalNonZeroSamples = 0;
const minRmsThreshold = 0.0003;
const samplesPerChunk = nativeRate * 4;
const maxSamplesPerChunk = nativeRate * 8;
const targetRate = 16000;
// Pre-roll: keep last 500ms of discarded silent chunks so that
// speech onsets at the tail of a silent window are preserved.
const preRollSamples = Math.ceil(nativeRate * 0.5);
const minFlushSamples = Math.ceil(nativeRate * 0.5);
// Adaptive flush: after ~1s silence following voiced content
const silenceFlushCallbacks = 6;
let hasVoicedContent = false;
let consecutiveSilentCallbacks = 0;
processor.onaudioprocess = (e: AudioProcessingEvent) => {
const input = e.inputBuffer.getChannelData(0);
callbackCount++;
// #region agent log
// Count non-zero samples on EVERY callback for accurate diagnostics
let nonZeroThisCallback = 0;
for (let i = 0; i < input.length; i++) {
if (input[i] !== 0) nonZeroThisCallback++;
@ -154,10 +156,32 @@ export class AudioCaptureProcedure {
}
// #endregion
// Per-callback voice activity detection
let cbPower = 0;
for (let i = 0; i < input.length; i++) {
cbPower += input[i] * input[i];
}
const cbRms = Math.sqrt(cbPower / Math.max(input.length, 1));
if (cbRms >= minRmsThreshold) {
hasVoicedContent = true;
consecutiveSilentCallbacks = 0;
} else {
consecutiveSilentCallbacks++;
}
chunkBuffer.push(new Float32Array(input));
samplesCollected += input.length;
if (samplesCollected >= samplesPerChunk) {
// Flush: max duration reached OR voiced content followed by ~1s silence
const shouldFlush = (
samplesCollected >= maxSamplesPerChunk
|| (hasVoicedContent
&& consecutiveSilentCallbacks >= silenceFlushCallbacks
&& samplesCollected > minFlushSamples)
);
if (shouldFlush) {
const merged = new Float32Array(samplesCollected);
let offset = 0;
for (const buf of chunkBuffer) {
@ -171,6 +195,9 @@ export class AudioCaptureProcedure {
}
const rms = Math.sqrt(powerSum / Math.max(merged.length, 1));
hasVoicedContent = false;
consecutiveSilentCallbacks = 0;
if (rms < minRmsThreshold) {
skippedSilentChunks++;
if (skippedSilentChunks % 10 === 0) {
@ -178,9 +205,6 @@ export class AudioCaptureProcedure {
`[AudioCapture] silent chunk skipped: track=${trackId}, readyState=${event.track.readyState}, muted=${event.track.muted}, enabled=${event.track.enabled}, rms=${rms.toFixed(6)}, callbacks=${callbackCount}, totalNonZero=${totalNonZeroSamples}`
);
}
// Pre-roll: retain the tail of the silent chunk so the next
// voiced chunk includes the speech onset that may have started
// in the last few hundred ms of this window.
const keep = Math.min(preRollSamples, merged.length);
const preRoll = merged.slice(merged.length - keep);
chunkBuffer = [preRoll];