initial commit

2026-06-08 22:49:50 -07:00
commit f6a6681e16
40 changed files with 3026 additions and 0 deletions
@@ -0,0 +1,10 @@
+<script lang="ts">
+  let count: number = $state(0)
+  const increment = () => {
+    count += 1
+  }
+</script>
+
+<button type="button" class="counter" onclick={increment}>
+  Count is {count}
+</button>
@@ -0,0 +1,99 @@
+import type { Marker, SwitchType } from '../types';
+import { app } from '../store.svelte';
+
+const SAMPLE_PATHS: Record<SwitchType, string> = {
+  'cherry-mx-blue': '/assets/samples/cherry-mx-blue.wav',
+  'cherry-mx-red': '/assets/samples/cherry-mx-red.wav',
+  'cherry-mx-brown': '/assets/samples/cherry-mx-brown.wav',
+};
+
+export type AudioEngine = {
+  init: (video: HTMLVideoElement) => Promise<void>;
+  reschedule: (currentTime: number, markers: Marker[], isPlaying: boolean) => void;
+  destroy: () => void;
+};
+
+export function createAudioEngine(): AudioEngine {
+  let ctx: AudioContext | null = null;
+  let videoSource: MediaElementAudioSourceNode | null = null;
+  let videoGain: GainNode | null = null;
+  const buffers = new Map<SwitchType, AudioBuffer>();
+  const scheduledSources: AudioBufferSourceNode[] = [];
+
+  async function ensureContext() {
+    if (!ctx) ctx = new AudioContext();
+    if (ctx.state === 'suspended') await ctx.resume();
+    return ctx;
+  }
+
+  async function loadBuffer(switchType: SwitchType): Promise<AudioBuffer> {
+    const cached = buffers.get(switchType);
+    if (cached) return cached;
+    const audioCtx = await ensureContext();
+    const response = await fetch(SAMPLE_PATHS[switchType]);
+    const arrayBuffer = await response.arrayBuffer();
+    const audioBuffer = await audioCtx.decodeAudioData(arrayBuffer);
+    buffers.set(switchType, audioBuffer);
+    return audioBuffer;
+  }
+
+  function clearScheduled() {
+    for (const source of scheduledSources) {
+      try {
+        source.stop();
+      } catch {
+        // already stopped
+      }
+    }
+    scheduledSources.length = 0;
+  }
+
+  return {
+    async init(video: HTMLVideoElement) {
+      const audioCtx = await ensureContext();
+      if (!videoSource) {
+        videoSource = audioCtx.createMediaElementSource(video);
+        videoGain = audioCtx.createGain();
+        videoSource.connect(videoGain);
+        videoGain.connect(audioCtx.destination);
+      }
+      await Promise.all(
+        (Object.keys(SAMPLE_PATHS) as SwitchType[]).map((id) => loadBuffer(id)),
+      );
+    },
+
+    reschedule(time: number, markers: Marker[], playing: boolean) {
+      if (!ctx || !playing) {
+        clearScheduled();
+        return;
+      }
+
+      clearScheduled();
+      const audioCtx = ctx;
+      const startAt = audioCtx.currentTime + 0.02;
+      const buffer = buffers.get(app.activeSwitch);
+      if (!buffer) return;
+
+      for (const marker of markers) {
+        if (marker.time < time - 0.05) continue;
+        const delay = marker.time - time;
+        const source = audioCtx.createBufferSource();
+        source.buffer = buffer;
+        source.connect(audioCtx.destination);
+        source.start(startAt + Math.max(0, delay));
+        scheduledSources.push(source);
+      }
+    },
+
+    destroy() {
+      clearScheduled();
+      videoSource?.disconnect();
+      videoGain?.disconnect();
+      void ctx?.close();
+      ctx = null;
+      videoSource = null;
+      videoGain = null;
+      buffers.clear();
+    },
+  };
+}
@@ -0,0 +1,47 @@
+const MODIFIER_KEYS = new Set([
+  'Control',
+  'Shift',
+  'Alt',
+  'Meta',
+  'CapsLock',
+  'Tab',
+  'Escape',
+]);
+
+const IGNORED_KEYS = new Set([
+  ...MODIFIER_KEYS,
+  'ArrowUp',
+  'ArrowDown',
+  'ArrowLeft',
+  'ArrowRight',
+  'Backspace',
+  'Delete',
+  'Enter',
+  ' ',
+]);
+
+export function isEditableTarget(target: EventTarget | null): boolean {
+  if (!(target instanceof HTMLElement)) return false;
+  const tag = target.tagName;
+  return tag === 'INPUT' || tag === 'SELECT' || tag === 'TEXTAREA' || target.isContentEditable;
+}
+
+export function keyLabel(event: KeyboardEvent): string | null {
+  if (event.ctrlKey && event.code === 'Space') return null;
+  if (IGNORED_KEYS.has(event.key)) return null;
+  if (event.key.length === 1) return event.key;
+  if (event.key === ' ') return 'Space';
+  return event.key;
+}
+
+export function shouldOverrideSelected(event: KeyboardEvent, hasSelection: boolean): boolean {
+  if (!hasSelection) return false;
+  if (event.ctrlKey || event.metaKey || event.altKey) return false;
+  if (['ArrowLeft', 'ArrowRight', 'ArrowUp', 'ArrowDown'].includes(event.key)) return false;
+  return keyLabel(event) !== null;
+}
+
+export function shouldRecordMarker(event: KeyboardEvent): boolean {
+  if (event.ctrlKey || event.metaKey || event.altKey) return false;
+  return keyLabel(event) !== null;
+}
@@ -0,0 +1,56 @@
+import type { Project } from './types';
+import { app, setActiveSwitch, setMarkers, setSelectedIds } from './store.svelte';
+
+export function buildProject(): Project {
+  return {
+    version: 1,
+    switch: app.activeSwitch,
+    markers: app.markers.map((m) => ({ ...m })),
+  };
+}
+
+export function downloadProject(filename = 'project.json') {
+  const project = buildProject();
+  const blob = new Blob([JSON.stringify(project, null, 2)], { type: 'application/json' });
+  const url = URL.createObjectURL(blob);
+  const anchor = document.createElement('a');
+  anchor.href = url;
+  anchor.download = filename;
+  anchor.click();
+  URL.revokeObjectURL(url);
+}
+
+export function loadProject(data: Project) {
+  if (data.version !== 1) {
+    throw new Error(`Unsupported project version: ${data.version}`);
+  }
+  setMarkers(data.markers.map((m) => ({ ...m })));
+  setActiveSwitch(data.switch);
+  setSelectedIds(new Set());
+}
+
+export async function exportAudio(duration: number) {
+  const project = buildProject();
+  const response = await fetch('/api/export/audio', {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({
+      duration,
+      switch: project.switch,
+      markers: project.markers,
+    }),
+  });
+
+  if (!response.ok) {
+    const detail = await response.text();
+    throw new Error(detail || 'Audio export failed');
+  }
+
+  const blob = await response.blob();
+  const url = URL.createObjectURL(blob);
+  const anchor = document.createElement('a');
+  anchor.href = url;
+  anchor.download = 'keyboard_track.wav';
+  anchor.click();
+  URL.revokeObjectURL(url);
+}
@@ -0,0 +1,132 @@
+import type { Marker, SwitchType } from './types';
+import { ZOOM_DEFAULT } from './types';
+
+export const app = $state({
+  markers: [] as Marker[],
+  selectedIds: new Set<string>(),
+  isPlaying: false,
+  currentTime: 0,
+  duration: 0,
+  fps: 30,
+  pixelsPerSecond: ZOOM_DEFAULT,
+  scrollLeft: 0,
+  activeSwitch: 'cherry-mx-blue' as SwitchType,
+  videoUrl: null as string | null,
+  videoName: null as string | null,
+  timelineWidth: 800,
+});
+
+let markerCounter = 0;
+
+export function createMarkerId(): string {
+  markerCounter += 1;
+  return `m${markerCounter}`;
+}
+
+export function setMarkers(value: Marker[]) {
+  app.markers = value;
+  const maxId = value.reduce((max, m) => {
+    const num = parseInt(m.id.replace(/\D/g, ''), 10);
+    return Number.isFinite(num) ? Math.max(max, num) : max;
+  }, 0);
+  markerCounter = maxId;
+}
+
+export function setSelectedIds(ids: Set<string>) {
+  app.selectedIds = ids;
+}
+
+export function setCurrentTime(value: number) {
+  app.currentTime = value;
+}
+
+export function setDuration(value: number) {
+  app.duration = value;
+}
+
+export function setIsPlaying(value: boolean) {
+  app.isPlaying = value;
+}
+
+export function setFps(value: number) {
+  app.fps = value;
+}
+
+export function setPixelsPerSecond(value: number) {
+  app.pixelsPerSecond = value;
+}
+
+export function setScrollLeft(value: number) {
+  app.scrollLeft = value;
+}
+
+export function setActiveSwitch(value: SwitchType) {
+  app.activeSwitch = value;
+}
+
+export function setTimelineWidth(value: number) {
+  app.timelineWidth = value;
+}
+
+export function addMarker(time: number, key: string): Marker {
+  const marker: Marker = { id: createMarkerId(), time, key };
+  app.markers = [...app.markers, marker].sort((a, b) => a.time - b.time);
+  return marker;
+}
+
+export function updateMarker(id: string, patch: Partial<Pick<Marker, 'time' | 'key'>>) {
+  app.markers = app.markers
+    .map((m) => (m.id === id ? { ...m, ...patch } : m))
+    .sort((a, b) => a.time - b.time);
+}
+
+export function setMarkerTimes(updates: Map<string, number>) {
+  app.markers = app.markers
+    .map((m) => {
+      const time = updates.get(m.id);
+      return time === undefined ? m : { ...m, time };
+    })
+    .sort((a, b) => a.time - b.time);
+}
+
+export function deleteMarkers(ids: Set<string>) {
+  app.markers = app.markers.filter((m) => !ids.has(m.id));
+  const next = new Set(app.selectedIds);
+  for (const id of ids) next.delete(id);
+  app.selectedIds = next;
+}
+
+export function selectAll() {
+  app.selectedIds = new Set(app.markers.map((m) => m.id));
+}
+
+export function toggleSelection(id: string, additive: boolean) {
+  const next = additive ? new Set(app.selectedIds) : new Set<string>();
+  if (next.has(id)) next.delete(id);
+  else next.add(id);
+  app.selectedIds = next;
+}
+
+export function setVideoUrl(url: string | null, name: string | null = null) {
+  if (app.videoUrl) URL.revokeObjectURL(app.videoUrl);
+  app.videoUrl = url;
+  app.videoName = name;
+}
+
+export function snapToFrame(time: number): number {
+  const frameDuration = 1 / app.fps;
+  return Math.round(time / frameDuration) * frameDuration;
+}
+
+export function nudgeSelected(deltaFrames: number) {
+  if (app.selectedIds.size === 0) return;
+  const frameDuration = 1 / app.fps;
+  const delta = deltaFrames * frameDuration;
+  app.markers = app.markers
+    .map((m) => {
+      if (!app.selectedIds.has(m.id)) return m;
+      const next = Math.max(0, Math.min(app.duration || Infinity, m.time + delta));
+      return { ...m, time: snapToFrame(next) };
+    })
+    .sort((a, b) => a.time - b.time);
+}
@@ -0,0 +1,353 @@
+<script lang="ts">
+  import {
+    app,
+    setMarkerTimes,
+    setPixelsPerSecond,
+    setScrollLeft,
+    setSelectedIds,
+    setTimelineWidth,
+    snapToFrame,
+    toggleSelection,
+  } from '../store.svelte';
+  import { ZOOM_MAX, ZOOM_MIN } from '../types';
+  import {
+    centerScrollOnPlayhead,
+    formatTime,
+    pxToTime,
+    tickInterval,
+    timeToPx,
+  } from './math';
+
+  interface Props {
+    onSeek?: (time: number) => void;
+    onReschedule?: () => void;
+  }
+
+  let { onSeek, onReschedule }: Props = $props();
+
+  let viewportEl: HTMLDivElement | undefined = $state();
+  let dragMode = $state<'none' | 'marker' | 'marquee' | 'move'>('none');
+  let dragMarkerId = $state<string | null>(null);
+  let dragStartX = 0;
+  let marqueeStart = 0;
+  let marqueeEnd = 0;
+  let moveStartTimes = new Map<string, number>();
+
+  function updateScrollCenter() {
+    setScrollLeft(
+      centerScrollOnPlayhead(app.currentTime, app.pixelsPerSecond, app.timelineWidth),
+    );
+  }
+
+  $effect(() => {
+    void app.currentTime;
+    void app.pixelsPerSecond;
+    if (app.duration > 0 && viewportEl) updateScrollCenter();
+  });
+
+  $effect(() => {
+    if (!viewportEl) return;
+    const observer = new ResizeObserver(() => {
+      setTimelineWidth(viewportEl!.clientWidth);
+    });
+    observer.observe(viewportEl);
+    setTimelineWidth(viewportEl.clientWidth);
+    return () => observer.disconnect();
+  });
+
+  function clampZoom(value: number) {
+    return Math.max(ZOOM_MIN, Math.min(ZOOM_MAX, value));
+  }
+
+  function handleWheel(event: WheelEvent) {
+    if (!event.altKey) return;
+    event.preventDefault();
+    const factor = event.deltaY < 0 ? 1.15 : 1 / 1.15;
+    setPixelsPerSecond(clampZoom(app.pixelsPerSecond * factor));
+    updateScrollCenter();
+  }
+
+  function localX(event: PointerEvent): number {
+    if (!viewportEl) return 0;
+    const rect = viewportEl.getBoundingClientRect();
+    return event.clientX - rect.left + app.scrollLeft;
+  }
+
+  function handlePointerDown(event: PointerEvent) {
+    if (!viewportEl) return;
+    const x = localX(event);
+    const time = pxToTime(x, app.pixelsPerSecond);
+    const target = event.target as HTMLElement;
+    const markerEl = target.closest('[data-marker-id]') as HTMLElement | null;
+
+    if (markerEl?.dataset.markerId) {
+      const id = markerEl.dataset.markerId;
+      toggleSelection(id, event.shiftKey);
+      dragMode = app.selectedIds.has(id) ? 'move' : 'marker';
+      dragMarkerId = id;
+      dragStartX = x;
+      moveStartTimes = new Map(
+        app.markers.filter((m) => app.selectedIds.has(m.id)).map((m) => [m.id, m.time]),
+      );
+      viewportEl.setPointerCapture(event.pointerId);
+      return;
+    }
+
+    if (!event.shiftKey) setSelectedIds(new Set());
+    dragMode = 'marquee';
+    marqueeStart = time;
+    marqueeEnd = time;
+    viewportEl.setPointerCapture(event.pointerId);
+  }
+
+  function handlePointerMove(event: PointerEvent) {
+    if (dragMode === 'none' || !viewportEl) return;
+    const x = localX(event);
+
+    if (dragMode === 'marquee') {
+      marqueeEnd = pxToTime(x, app.pixelsPerSecond);
+      return;
+    }
+
+    if (dragMode === 'move' && moveStartTimes.size > 0) {
+      const deltaTime = pxToTime(x - dragStartX, app.pixelsPerSecond);
+      const updates = new Map<string, number>();
+      for (const [id, start] of moveStartTimes) {
+        const next = Math.max(0, Math.min(app.duration || Infinity, start + deltaTime));
+        updates.set(id, snapToFrame(next));
+      }
+      setMarkerTimes(updates);
+      return;
+    }
+
+    if (dragMode === 'marker' && dragMarkerId) {
+      const time = snapToFrame(
+        Math.max(0, Math.min(app.duration || Infinity, pxToTime(x, app.pixelsPerSecond))),
+      );
+      setMarkerTimes(new Map([[dragMarkerId, time]]));
+    }
+  }
+
+  function handlePointerUp(event: PointerEvent) {
+    if (dragMode === 'marquee') {
+      const minT = Math.min(marqueeStart, marqueeEnd);
+      const maxT = Math.max(marqueeStart, marqueeEnd);
+      const hits = app.markers.filter((m) => m.time >= minT && m.time <= maxT).map((m) => m.id);
+      setSelectedIds(new Set(hits));
+    }
+
+    if (dragMode === 'move' || dragMode === 'marker') {
+      onReschedule?.();
+    }
+
+    dragMode = 'none';
+    dragMarkerId = null;
+    moveStartTimes.clear();
+    viewportEl?.releasePointerCapture(event.pointerId);
+  }
+
+  function handleRulerClick(event: MouseEvent) {
+    if (dragMode !== 'none') return;
+    const x = localX(event as unknown as PointerEvent);
+    const time = snapToFrame(
+      Math.max(0, Math.min(app.duration || Infinity, pxToTime(x, app.pixelsPerSecond))),
+    );
+    onSeek?.(time);
+  }
+
+  function handleZoomInput(event: Event) {
+    const value = Number((event.currentTarget as HTMLInputElement).value);
+    setPixelsPerSecond(value);
+    updateScrollCenter();
+  }
+
+  const contentWidth = $derived(
+    Math.max(app.timelineWidth, timeToPx(app.duration || 1, app.pixelsPerSecond) + 40),
+  );
+  const ticks = $derived.by(() => {
+    const interval = tickInterval(app.pixelsPerSecond);
+    const count = Math.ceil((app.duration || 1) / interval);
+    return Array.from({ length: count + 1 }, (_, i) => i * interval);
+  });
+  const playheadX = $derived(timeToPx(app.currentTime, app.pixelsPerSecond));
+  const marqueeVisible = $derived(dragMode === 'marquee');
+  const marqueeLeft = $derived(timeToPx(Math.min(marqueeStart, marqueeEnd), app.pixelsPerSecond));
+  const marqueeWidth = $derived(
+    Math.abs(
+      timeToPx(marqueeEnd, app.pixelsPerSecond) - timeToPx(marqueeStart, app.pixelsPerSecond),
+    ),
+  );
+</script>
+
+<div class="timeline-panel">
+  <div class="zoom-row">
+    <label for="zoom-slider">Zoom</label>
+    <input
+      id="zoom-slider"
+      type="range"
+      min={ZOOM_MIN}
+      max={ZOOM_MAX}
+      value={app.pixelsPerSecond}
+      oninput={handleZoomInput}
+    />
+    <span class="hint">Alt + scroll to zoom</span>
+  </div>
+
+  <div class="timeline-viewport" bind:this={viewportEl} onwheel={handleWheel}>
+    <div
+      class="timeline-content"
+      style="width: {contentWidth}px; transform: translateX({-app.scrollLeft}px);"
+    >
+      <!-- svelte-ignore a11y_click_events_have_key_events -->
+      <!-- svelte-ignore a11y_no_static_element_interactions -->
+      <div
+        class="ruler"
+        onclick={handleRulerClick}
+        onpointerdown={handlePointerDown}
+        onpointermove={handlePointerMove}
+        onpointerup={handlePointerUp}
+      >
+        {#each ticks as tick}
+          <div class="tick" style="left: {timeToPx(tick, app.pixelsPerSecond)}px">
+            <span>{formatTime(tick)}</span>
+          </div>
+        {/each}
+      </div>
+
+      <!-- svelte-ignore a11y_no_static_element_interactions -->
+      <div
+        class="track"
+        onpointerdown={handlePointerDown}
+        onpointermove={handlePointerMove}
+        onpointerup={handlePointerUp}
+      >
+        {#each app.markers as marker (marker.id)}
+          <button
+            type="button"
+            class="marker"
+            class:selected={app.selectedIds.has(marker.id)}
+            data-marker-id={marker.id}
+            style="left: {timeToPx(marker.time, app.pixelsPerSecond)}px"
+            title="{marker.key} @ {formatTime(marker.time)}"
+          >
+            {marker.key}
+          </button>
+        {/each}
+
+        {#if marqueeVisible}
+          <div class="marquee" style="left: {marqueeLeft}px; width: {marqueeWidth}px"></div>
+        {/if}
+
+        <div class="playhead" style="left: {playheadX}px"></div>
+      </div>
+    </div>
+  </div>
+</div>
+
+<style>
+  .timeline-panel {
+    display: flex;
+    flex-direction: column;
+    gap: 0.5rem;
+    border-top: 1px solid #333;
+    padding-top: 0.75rem;
+  }
+
+  .zoom-row {
+    display: flex;
+    align-items: center;
+    gap: 0.75rem;
+    font-size: 0.85rem;
+    color: #aaa;
+  }
+
+  .zoom-row input[type='range'] {
+    flex: 1;
+    max-width: 240px;
+  }
+
+  .hint {
+    margin-left: auto;
+  }
+
+  .timeline-viewport {
+    position: relative;
+    overflow: hidden;
+    height: 120px;
+    background: #1a1a1a;
+    border: 1px solid #333;
+    border-radius: 6px;
+    user-select: none;
+    touch-action: none;
+  }
+
+  .timeline-content {
+    position: relative;
+    height: 100%;
+    will-change: transform;
+  }
+
+  .ruler {
+    position: relative;
+    height: 28px;
+    border-bottom: 1px solid #333;
+    background: #222;
+    cursor: pointer;
+  }
+
+  .tick {
+    position: absolute;
+    top: 0;
+    height: 100%;
+    border-left: 1px solid #444;
+    padding-left: 4px;
+    font-size: 0.65rem;
+    color: #888;
+    pointer-events: none;
+  }
+
+  .track {
+    position: relative;
+    height: calc(100% - 28px);
+    cursor: crosshair;
+  }
+
+  .marker {
+    position: absolute;
+    top: 18px;
+    transform: translateX(-50%);
+    padding: 0.2rem 0.45rem;
+    border: 1px solid #555;
+    border-radius: 4px;
+    background: #2d3748;
+    color: #e2e8f0;
+    font-size: 0.75rem;
+    cursor: grab;
+    white-space: nowrap;
+  }
+
+  .marker.selected {
+    background: #3182ce;
+    border-color: #63b3ed;
+    box-shadow: 0 0 0 1px #63b3ed;
+  }
+
+  .marquee {
+    position: absolute;
+    top: 8px;
+    height: 72px;
+    background: rgba(99, 179, 237, 0.2);
+    border: 1px solid #63b3ed;
+    pointer-events: none;
+  }
+
+  .playhead {
+    position: absolute;
+    top: 0;
+    bottom: 0;
+    width: 2px;
+    background: #f56565;
+    pointer-events: none;
+    z-index: 2;
+  }
+</style>
@@ -0,0 +1,30 @@
+export function timeToPx(time: number, pixelsPerSecond: number): number {
+  return time * pixelsPerSecond;
+}
+
+export function pxToTime(px: number, pixelsPerSecond: number): number {
+  return px / pixelsPerSecond;
+}
+
+export function centerScrollOnPlayhead(
+  playheadTime: number,
+  pixelsPerSecond: number,
+  viewportWidth: number,
+): number {
+  const playheadPx = timeToPx(playheadTime, pixelsPerSecond);
+  return Math.max(0, playheadPx - viewportWidth / 2);
+}
+
+export function formatTime(seconds: number): string {
+  const mins = Math.floor(seconds / 60);
+  const secs = seconds % 60;
+  return `${mins}:${secs.toFixed(2).padStart(5, '0')}`;
+}
+
+export function tickInterval(pixelsPerSecond: number): number {
+  if (pixelsPerSecond >= 200) return 0.1;
+  if (pixelsPerSecond >= 100) return 0.5;
+  if (pixelsPerSecond >= 50) return 1;
+  if (pixelsPerSecond >= 25) return 2;
+  return 5;
+}
@@ -0,0 +1,23 @@
+export type SwitchType = 'cherry-mx-blue' | 'cherry-mx-red' | 'cherry-mx-brown';
+
+export interface Marker {
+  id: string;
+  time: number;
+  key: string;
+}
+
+export interface Project {
+  version: number;
+  switch: SwitchType;
+  markers: Marker[];
+}
+
+export const SWITCH_OPTIONS: { id: SwitchType; label: string }[] = [
+  { id: 'cherry-mx-blue', label: 'Cherry MX Blue (clicky)' },
+  { id: 'cherry-mx-red', label: 'Cherry MX Red (linear)' },
+  { id: 'cherry-mx-brown', label: 'Cherry MX Brown (tactile)' },
+];
+
+export const ZOOM_MIN = 20;
+export const ZOOM_MAX = 400;
+export const ZOOM_DEFAULT = 80;
@@ -0,0 +1,103 @@
+import { app, setCurrentTime, setDuration, setFps, setIsPlaying, snapToFrame } from '../store.svelte';
+
+export type VideoController = {
+  element: HTMLVideoElement;
+  destroy: () => void;
+  togglePlayPause: () => void;
+  stepFrame: (delta: number) => void;
+  seek: (time: number) => void;
+};
+
+export function attachVideoPlayer(video: HTMLVideoElement): VideoController {
+  let rafId = 0;
+  let lastFrameTime: number | null = null;
+  const frameDeltas: number[] = [];
+
+  const onLoadedMetadata = () => {
+    setDuration(video.duration);
+    setCurrentTime(video.currentTime);
+  };
+
+  const onPlay = () => setIsPlaying(true);
+  const onPause = () => setIsPlaying(false);
+  const onSeeked = () => setCurrentTime(video.currentTime);
+  const onEnded = () => setIsPlaying(false);
+
+  const detectFps = (mediaTime: number) => {
+    if (lastFrameTime !== null) {
+      const delta = mediaTime - lastFrameTime;
+      if (delta > 0.001 && delta < 0.2) {
+        frameDeltas.push(delta);
+        if (frameDeltas.length > 30) frameDeltas.shift();
+        if (frameDeltas.length >= 10) {
+          const avg = frameDeltas.reduce((a, b) => a + b, 0) / frameDeltas.length;
+          const detected = Math.round(1 / avg);
+          if (detected >= 10 && detected <= 120) setFps(detected);
+        }
+      }
+    }
+    lastFrameTime = mediaTime;
+  };
+
+  const frameLoop = (_now: number, metadata: VideoFrameCallbackMetadata) => {
+    setCurrentTime(metadata.mediaTime);
+    detectFps(metadata.mediaTime);
+    if (!video.paused && !video.ended) {
+      video.requestVideoFrameCallback(frameLoop);
+    }
+  };
+
+  const timeLoop = () => {
+    if (!video.paused) {
+      setCurrentTime(video.currentTime);
+      rafId = requestAnimationFrame(timeLoop);
+    }
+  };
+
+  const onPlayStart = () => {
+    if ('requestVideoFrameCallback' in video) {
+      video.requestVideoFrameCallback(frameLoop);
+    } else {
+      rafId = requestAnimationFrame(timeLoop);
+    }
+  };
+
+  video.addEventListener('loadedmetadata', onLoadedMetadata);
+  video.addEventListener('play', onPlay);
+  video.addEventListener('play', onPlayStart);
+  video.addEventListener('pause', onPause);
+  video.addEventListener('seeked', onSeeked);
+  video.addEventListener('ended', onEnded);
+
+  if (video.readyState >= 1) onLoadedMetadata();
+
+  return {
+    element: video,
+    destroy() {
+      cancelAnimationFrame(rafId);
+      video.removeEventListener('loadedmetadata', onLoadedMetadata);
+      video.removeEventListener('play', onPlay);
+      video.removeEventListener('play', onPlayStart);
+      video.removeEventListener('pause', onPause);
+      video.removeEventListener('seeked', onSeeked);
+      video.removeEventListener('ended', onEnded);
+    },
+    togglePlayPause() {
+      if (video.paused || video.ended) void video.play();
+      else video.pause();
+    },
+    stepFrame(delta: number) {
+      video.pause();
+      const next = snapToFrame(
+        Math.max(0, Math.min(video.duration || 0, video.currentTime + delta / app.fps)),
+      );
+      video.currentTime = next;
+      setCurrentTime(next);
+    },
+    seek(time: number) {
+      const clamped = Math.max(0, Math.min(video.duration || 0, time));
+      video.currentTime = clamped;
+      setCurrentTime(clamped);
+    },
+  };
+}