From 3e89d2998588f8e35c524e523ba2ee853f0f6475 Mon Sep 17 00:00:00 2001
From: Maze Winther <mazewinther@gmail.com>
Date: Mon, 20 Apr 2026 11:31:17 +0200
Subject: refactor: restructure files to their domains,  new preview overlay
 system, and dep graph

---
 apps/web/src/lib/retime/audio-stretch.ts | 182 -------------------------------
 1 file changed, 182 deletions(-)
 delete mode 100644 apps/web/src/lib/retime/audio-stretch.ts

(limited to 'apps/web/src/lib/retime/audio-stretch.ts')

diff --git a/apps/web/src/lib/retime/audio-stretch.ts b/apps/web/src/lib/retime/audio-stretch.ts
deleted file mode 100644
index 92902dff..00000000
--- a/apps/web/src/lib/retime/audio-stretch.ts
+++ /dev/null
@@ -1,182 +0,0 @@
-import { PitchShifter } from "soundtouchjs";
-import { clampRetimeRate, shouldMaintainPitch } from "@/lib/retime/rate";
-import type { RetimeConfig } from "@/lib/timeline";
-import { getSourceTimeAtClipTime } from "./resolve";
-
-const RATE_EPSILON = 1e-6;
-
-function sampleLinear({
-	channelData,
-	position,
-}: {
-	channelData: Float32Array;
-	position: number;
-}): number {
-	if (position <= 0) {
-		return channelData[0] ?? 0;
-	}
-	const lower = Math.floor(position);
-	const upper = Math.min(channelData.length - 1, lower + 1);
-	if (lower >= channelData.length) {
-		return 0;
-	}
-	const fraction = position - lower;
-	return channelData[lower] * (1 - fraction) + channelData[upper] * fraction;
-}
-
-function buildResampledBuffer({
-	audioContext,
-	sourceBuffer,
-	trimStart,
-	clipDuration,
-	targetSampleRate,
-	retime,
-}: {
-	audioContext: BaseAudioContext;
-	sourceBuffer: AudioBuffer;
-	trimStart: number;
-	clipDuration: number;
-	targetSampleRate: number;
-	retime?: RetimeConfig;
-}): AudioBuffer {
-	const outputLength = Math.max(1, Math.ceil(clipDuration * targetSampleRate));
-	const numChannels = Math.max(1, Math.min(2, sourceBuffer.numberOfChannels));
-	const outputBuffer = audioContext.createBuffer(
-		numChannels,
-		outputLength,
-		targetSampleRate,
-	);
-
-	for (let channel = 0; channel < numChannels; channel++) {
-		const sourceData = sourceBuffer.getChannelData(
-			Math.min(channel, sourceBuffer.numberOfChannels - 1),
-		);
-		const outputData = outputBuffer.getChannelData(channel);
-
-		for (let i = 0; i < outputLength; i++) {
-			const clipTime = i / targetSampleRate;
-			const sourceTime =
-				trimStart + getSourceTimeAtClipTime({ clipTime, retime });
-			outputData[i] = sampleLinear({
-				channelData: sourceData,
-				position: sourceTime * sourceBuffer.sampleRate,
-			});
-		}
-	}
-
-	return outputBuffer;
-}
-
-async function buildPitchPreservedBuffer({
-	sourceBuffer,
-	trimStart,
-	clipDuration,
-	rate,
-	targetSampleRate,
-}: {
-	sourceBuffer: AudioBuffer;
-	trimStart: number;
-	clipDuration: number;
-	rate: number;
-	targetSampleRate: number;
-}): Promise<AudioBuffer> {
-	const nativeSampleRate = sourceBuffer.sampleRate;
-	const sourceDuration = clipDuration * rate;
-	const startSample = Math.max(0, Math.floor(trimStart * nativeSampleRate));
-	const numSourceSamples = Math.max(
-		1,
-		Math.ceil(sourceDuration * nativeSampleRate),
-	);
-	const available = Math.max(0, sourceBuffer.length - startSample);
-	const actualSamples = Math.max(1, Math.min(numSourceSamples, available));
-	const numChannels = Math.max(1, Math.min(2, sourceBuffer.numberOfChannels));
-
-	// Resample to targetSampleRate first — soundtouchjs reads raw channel data
-	// and does not respect the source buffer's native sample rate.
-	const resampledLength = Math.max(
-		1,
-		Math.ceil(sourceDuration * targetSampleRate),
-	);
-	const resampleCtx = new OfflineAudioContext(
-		numChannels,
-		resampledLength,
-		targetSampleRate,
-	);
-	const nativeBuffer = resampleCtx.createBuffer(
-		numChannels,
-		actualSamples,
-		nativeSampleRate,
-	);
-
-	for (let ch = 0; ch < numChannels; ch++) {
-		const src = sourceBuffer.getChannelData(
-			Math.min(ch, sourceBuffer.numberOfChannels - 1),
-		);
-		nativeBuffer.copyToChannel(
-			src.subarray(startSample, startSample + actualSamples),
-			ch,
-		);
-	}
-
-	const resampleSourceNode = resampleCtx.createBufferSource();
-	resampleSourceNode.buffer = nativeBuffer;
-	resampleSourceNode.connect(resampleCtx.destination);
-	resampleSourceNode.start(0);
-	const resampledBuffer = await resampleCtx.startRendering();
-
-	const outputSamples = Math.max(
-		1,
-		Math.ceil(clipDuration * targetSampleRate),
-	);
-	const stretchCtx = new OfflineAudioContext(
-		numChannels,
-		outputSamples,
-		targetSampleRate,
-	);
-	const shifter = new PitchShifter(stretchCtx, resampledBuffer, 4096);
-	shifter.tempo = rate;
-	shifter.pitch = 1;
-	shifter.connect(stretchCtx.destination);
-	return stretchCtx.startRendering();
-}
-
-export async function renderRetimedBuffer({
-	audioContext,
-	sourceBuffer,
-	trimStart,
-	clipDuration,
-	retime,
-	maintainPitch = false,
-}: {
-	audioContext: BaseAudioContext;
-	sourceBuffer: AudioBuffer;
-	trimStart: number;
-	clipDuration: number;
-	retime?: RetimeConfig;
-	maintainPitch?: boolean;
-}): Promise<AudioBuffer> {
-	const targetSampleRate = audioContext.sampleRate;
-	const rate = clampRetimeRate({ rate: retime?.rate ?? 1 });
-	const usePitchPreservation =
-		shouldMaintainPitch({ rate, maintainPitch }) &&
-		Math.abs(rate - 1) > RATE_EPSILON;
-
-	if (usePitchPreservation) {
-		return buildPitchPreservedBuffer({
-			sourceBuffer,
-			trimStart,
-			clipDuration,
-			rate,
-			targetSampleRate,
-		});
-	}
-
-	return buildResampledBuffer({
-		audioContext,
-		sourceBuffer,
-		trimStart,
-		clipDuration,
-		targetSampleRate,
-		retime,
-	});
-}
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