feat: add transport controls and keyboard shortcuts

Centralize seek/play/frame/shuttle in playback helpers, wire the transport bar, and handle global shortcuts from App.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/App.svelte

@@ -8,15 +8,101 @@
   import SetupWizard from '$lib/components/SetupWizard.svelte';
   import PreferencesPanel from '$lib/components/PreferencesPanel.svelte';
   import { loadPreferences } from '$lib/stores/preferences.svelte';
+  import { getSelectedClipId, removeClip } from '$lib/stores/clips.svelte';
+  import { adjustShuttle } from '$lib/transport/playback';
+  import type { TransportKeyAction } from '$lib/transport/playback';
 
   let showSetupWizard = $state(true);
   let showPreferences = $state(false);
+  let showExportDialog = $state(false);
+  let shuttleRate = $state(1);
+
+  let transportControls = $state<TransportControls | null>(null);
 
   $effect(() => {
     loadPreferences();
   });
+
+  function dispatchTransport(action: TransportKeyAction) {
+    transportControls?.handleKeyAction(action);
+  }
+
+  function handleGlobalKeydown(e: KeyboardEvent) {
+    const target = e.target as HTMLElement;
+    if (target.tagName === 'INPUT' || target.tagName === 'TEXTAREA') return;
+
+    switch (e.key) {
+      case ' ':
+        e.preventDefault();
+        dispatchTransport('play-pause');
+        break;
+      case ',':
+        e.preventDefault();
+        dispatchTransport(e.shiftKey ? 'keyframe-back' : 'frame-back');
+        break;
+      case '.':
+        e.preventDefault();
+        dispatchTransport(e.shiftKey ? 'keyframe-forward' : 'frame-forward');
+        break;
+      case 'ArrowLeft':
+        e.preventDefault();
+        dispatchTransport(e.shiftKey ? 'seek-back-1' : 'seek-back-5');
+        break;
+      case 'ArrowRight':
+        e.preventDefault();
+        dispatchTransport(e.shiftKey ? 'seek-forward-1' : 'seek-forward-5');
+        break;
+      case 'i':
+      case 'I':
+        e.preventDefault();
+        dispatchTransport('mark-in');
+        break;
+      case 'o':
+      case 'O':
+        e.preventDefault();
+        dispatchTransport('mark-out');
+        break;
+      case 'j':
+      case 'J':
+        e.preventDefault();
+        shuttleRate = adjustShuttle(-1, shuttleRate);
+        break;
+      case 'k':
+      case 'K':
+        e.preventDefault();
+        dispatchTransport('play-pause');
+        break;
+      case 'l':
+      case 'L':
+        e.preventDefault();
+        shuttleRate = adjustShuttle(1, shuttleRate);
+        break;
+      case 'Delete':
+      case 'Backspace': {
+        e.preventDefault();
+        const selectedId = getSelectedClipId();
+        if (selectedId) removeClip(selectedId);
+        break;
+      }
+      case 'a':
+        if (e.metaKey) {
+          e.preventDefault();
+        }
+        break;
+      case 'e':
+        if (e.metaKey) {
+          e.preventDefault();
+          showExportDialog = true;
+        }
+        break;
+      default:
+        break;
+    }
+  }
 </script>
 
+<svelte:window onkeydown={handleGlobalKeydown} />
+
 {#if showSetupWizard}
   <SetupWizard onComplete={() => (showSetupWizard = false)} />
 {/if}
@@ -33,7 +119,7 @@
 
   <main class="content">
     <VideoPlayer />
-    <TransportControls />
+    <TransportControls bind:this={transportControls} />
     <Timeline />
     <ClipList />
   </main>

src/lib/components/TransportControls.svelte

@@ -1,5 +1,76 @@
+<script lang="ts">
+  import { session } from '$lib/stores/videoSession.svelte';
+  import { markInPoint, markOutPoint } from '$lib/stores/clips.svelte';
+  import { formatTime } from '$lib/utils/time';
+  import {
+    jumpKeyframe,
+    runTransportAction,
+    seekBy,
+    stepFrame,
+    togglePlayPause,
+    type TransportKeyAction,
+  } from '$lib/transport/playback';
+
+  let hasKeyframes = $derived(session.keyframePositions.length > 0);
+
+  export function handleKeyAction(action: TransportKeyAction) {
+    runTransportAction(action, markInPoint, markOutPoint);
+  }
+</script>
+
 <div class="transport-controls">
-  <span class="placeholder-text">Transport controls</span>
+  <div class="buttons">
+    <button
+      onclick={() => jumpKeyframe(-1)}
+      disabled={!hasKeyframes}
+      title="Previous keyframe (Shift+,)"
+      type="button"
+    >
+      ◄K
+    </button>
+    <button onclick={() => seekBy(-5)} title="Seek back 5s (←)" type="button">-5s</button>
+    <button onclick={() => seekBy(-1)} title="Seek back 1s (Shift+←)" type="button">-1s</button>
+    <button onclick={() => stepFrame(-1)} title="Previous frame (,)" type="button">◄|</button>
+    <button onclick={togglePlayPause} title="Play/Pause (Space / K)" type="button">
+      {session.isPlaying ? '❚❚' : '▶'}
+    </button>
+    <button onclick={() => stepFrame(1)} title="Next frame (.)" type="button">|►</button>
+    <button onclick={() => seekBy(1)} title="Seek forward 1s (Shift+→)" type="button">+1s</button>
+    <button onclick={() => seekBy(5)} title="Seek forward 5s (→)" type="button">+5s</button>
+    <button
+      onclick={() => jumpKeyframe(1)}
+      disabled={!hasKeyframes}
+      title="Next keyframe (Shift+.)"
+      type="button"
+    >
+      K►
+    </button>
+  </div>
+
+  <div class="time-display">
+    <span class="current">{formatTime(session.currentTime)}</span>
+    <span class="separator">/</span>
+    <span class="total">{formatTime(session.duration)}</span>
+  </div>
+
+  <div class="mark-buttons">
+    <button
+      class="mark-btn"
+      onclick={() => markInPoint(session.currentTime)}
+      title="Set in-point (I)"
+      type="button"
+    >
+      I
+    </button>
+    <button
+      class="mark-btn"
+      onclick={() => markOutPoint(session.currentTime)}
+      title="Set out-point (O)"
+      type="button"
+    >
+      O
+    </button>
+  </div>
 </div>
 
 <style>
@@ -10,10 +81,50 @@
     background: var(--bg-secondary);
     border-top: 1px solid var(--border);
     border-bottom: 1px solid var(--border);
-    min-height: 40px;
+    gap: 16px;
   }
-  .placeholder-text {
-    color: var(--text-muted);
+
+  .buttons {
+    display: flex;
+    gap: 4px;
+    flex-wrap: wrap;
+  }
+
+  .buttons button {
     font-size: 13px;
+    padding: 4px 8px;
+    min-width: 32px;
+  }
+
+  .time-display {
+    font-family: var(--font-mono);
+    font-size: 14px;
+  }
+
+  .current {
+    color: var(--text-primary);
+  }
+
+  .separator {
+    color: var(--text-muted);
+    margin: 0 4px;
+  }
+
+  .total {
+    color: var(--text-secondary);
+  }
+
+  .mark-buttons {
+    margin-left: auto;
+    display: flex;
+    gap: 4px;
+  }
+
+  .mark-btn {
+    font-weight: 700;
+    font-size: 14px;
+    padding: 4px 12px;
+    background: var(--bg-tertiary);
+    border: 1px solid var(--border);
   }
 </style>

src/lib/transport/playback.ts

@@ -0,0 +1,116 @@
+import { session } from '$lib/stores/videoSession.svelte';
+
+export function seekTo(time: number) {
+  const clamped = Math.max(0, Math.min(time, session.duration));
+  session.currentTime = clamped;
+  const videoEl = document.querySelector('video');
+  if (videoEl) {
+    videoEl.currentTime = clamped;
+  }
+}
+
+export function seekBy(seconds: number) {
+  seekTo(session.currentTime + seconds);
+}
+
+export function togglePlayPause() {
+  const videoEl = document.querySelector('video');
+  if (!videoEl) return;
+  if (videoEl.paused) {
+    void videoEl.play();
+  } else {
+    videoEl.pause();
+  }
+}
+
+export function stepFrame(direction: 1 | -1) {
+  const videoEl = document.querySelector('video');
+  if (videoEl && !videoEl.paused) {
+    videoEl.pause();
+  }
+  seekTo(session.currentTime + direction * (1 / session.fps));
+}
+
+export function jumpKeyframe(direction: 1 | -1) {
+  if (session.keyframePositions.length === 0) return;
+  const positions = session.keyframePositions;
+
+  if (direction > 0) {
+    const next = positions.find((p) => p > session.currentTime + 0.01);
+    if (next !== undefined) seekTo(next);
+  } else {
+    const prev = [...positions].reverse().find((p) => p < session.currentTime - 0.01);
+    if (prev !== undefined) seekTo(prev);
+  }
+}
+
+export function adjustShuttle(dir: 1 | -1, shuttleRate: number): number {
+  const videoEl = document.querySelector('video');
+  if (!videoEl) return shuttleRate;
+
+  const nextRate = Math.max(0.25, Math.min(4, shuttleRate + dir * 0.5));
+  videoEl.playbackRate = nextRate;
+  if (videoEl.paused) {
+    void videoEl.play();
+  }
+  return nextRate;
+}
+
+export type TransportKeyAction =
+  | 'play-pause'
+  | 'frame-back'
+  | 'frame-forward'
+  | 'keyframe-back'
+  | 'keyframe-forward'
+  | 'seek-back-5'
+  | 'seek-forward-5'
+  | 'seek-back-1'
+  | 'seek-forward-1'
+  | 'mark-in'
+  | 'mark-out';
+
+export function runTransportAction(
+  action: TransportKeyAction,
+  markIn: (time: number) => void,
+  markOut: (time: number) => void
+) {
+  switch (action) {
+    case 'play-pause':
+      togglePlayPause();
+      break;
+    case 'frame-back':
+      stepFrame(-1);
+      break;
+    case 'frame-forward':
+      stepFrame(1);
+      break;
+    case 'keyframe-back':
+      jumpKeyframe(-1);
+      break;
+    case 'keyframe-forward':
+      jumpKeyframe(1);
+      break;
+    case 'seek-back-5':
+      seekBy(-5);
+      break;
+    case 'seek-forward-5':
+      seekBy(5);
+      break;
+    case 'seek-back-1':
+      seekBy(-1);
+      break;
+    case 'seek-forward-1':
+      seekBy(1);
+      break;
+    case 'mark-in':
+      markIn(session.currentTime);
+      break;
+    case 'mark-out':
+      markOut(session.currentTime);
+      break;
+    default: {
+      const _exhaustive: never = action;
+      void _exhaustive;
+    }
+  }
+}