fix(overlay): drive timing review playhead from mpv playback position

- Preview session observes time-pos, waits for loaded media before seeking, and acks each command
- Forward positions to the modal over media-timing-review:preview-position
- Cursor follows the real position, pauses while buffering, and stays at the clip end when done
- Replace the fixed end-of-clip timer with a 15s stall timeout
- Document preview cursor behavior and ownership in docs

src/core/services/media-timing-preview.test.ts

@@ -1,5 +1,6 @@
 import assert from 'node:assert/strict';
 import { EventEmitter } from 'node:events';
+import { ChildProcess } from 'node:child_process';
 import net from 'node:net';
 import { describe, test } from 'node:test';
 import { buildMediaTimingPreviewArgs, MediaTimingPreviewSession } from './media-timing-preview';
@@ -217,6 +218,15 @@ function createFakeSocket() {
   socket.destroyed = false;
   socket.write = (data) => {
     writes.push(data);
+    const message = JSON.parse(data);
+    if (message.request_id !== undefined) {
+      queueMicrotask(() =>
+        socket.emit(
+          'data',
+          `${JSON.stringify({ request_id: message.request_id, error: 'success' })}\n`,
+        ),
+      );
+    }
     return true;
   };
   socket.end = () => undefined;
@@ -226,6 +236,85 @@ function createFakeSocket() {
   return { socket, writes };
 }
 
+test('preview waits for loaded media before seeking and reports the actual playback position', async () => {
+  const { socket, writes } = createFakeSocket();
+  const child = new ChildProcess();
+  child.kill = () => true;
+  const positions: number[] = [];
+  const session = new MediaTimingPreviewSession({
+    spawnProcess: () => child,
+    connectSocket: () => {
+      queueMicrotask(() => socket.emit('connect'));
+      return socket as never;
+    },
+    removeSocketFile: () => undefined,
+    createSocketPath: () => '/tmp/review.sock',
+  });
+  const position = (data: number) =>
+    socket.emit(
+      'data',
+      `${JSON.stringify({ event: 'property-change', name: 'time-pos', data })}\n`,
+    );
+  try {
+    await session.start({
+      mediaPath: '/video/show.mkv',
+      onPlaybackPosition: (time) => positions.push(time),
+    });
+    const playing = session.play(36, 42);
+    await Promise.resolve();
+    assert.equal(
+      writes.some((line) => JSON.parse(line).command[0] === 'seek'),
+      false,
+    );
+    position(0);
+    await playing;
+    position(36);
+    position(39);
+    // No advancing position means no fabricated progress, even while audio is stalled.
+    assert.deepEqual(positions, [36, 39]);
+    position(41.9);
+    assert.deepEqual(positions, [36, 39, 41.9]);
+    await session.stop();
+    position(42);
+    assert.deepEqual(positions, [36, 39, 41.9]);
+  } finally {
+    session.dispose();
+  }
+});
+
+for (const action of ['stop', 'dispose'] as const) {
+  test(`${action} cancels a preview still waiting for media to load`, async () => {
+    const { socket, writes } = createFakeSocket();
+    const child = new ChildProcess();
+    child.kill = () => true;
+    const session = new MediaTimingPreviewSession({
+      spawnProcess: () => child,
+      connectSocket: () => {
+        queueMicrotask(() => socket.emit('connect'));
+        return socket as never;
+      },
+      removeSocketFile: () => undefined,
+      createSocketPath: () => '/tmp/review.sock',
+    });
+    try {
+      await session.start({ mediaPath: '/video/show.mkv' });
+      const pending = assert.rejects(session.play(36, 42), /closed|cancelled/);
+      await session[action]();
+      await pending;
+      socket.emit(
+        'data',
+        `${JSON.stringify({ event: 'property-change', name: 'time-pos', data: 0 })}\n`,
+      );
+      assert.equal(
+        writes.some((line) => JSON.parse(line).command[0] === 'seek'),
+        false,
+      );
+    } finally {
+      session.dispose();
+    }
+  });
+}
+
 test('preview session plays once to the clip end and reports when mpv has drained it', async () => {
   const { socket, writes } = createFakeSocket();
   const child = new EventEmitter() as EventEmitter & { kill: () => boolean };
@@ -253,11 +342,16 @@ test('preview session plays once to the clip end and reports when mpv has draine
     [
       ['observe_property', 1, 'eof-reached'],
       ['observe_property', 2, 'pause'],
+      ['observe_property', 3, 'time-pos'],
     ],
   );
   // The observers' initial replies describe the idle paused player, not a finished preview.
   socket.emit('data', property('eof-reached', false) + property('pause', true));
   assert.equal(endedCount, 0);
+  socket.emit(
+    'data',
+    `${JSON.stringify({ event: 'property-change', name: 'time-pos', data: 0 })}\n`,
+  );
 
   writes.length = 0;
   await session.play(12.25, 14.5);
@@ -265,8 +359,8 @@ test('preview session plays once to the clip end and reports when mpv has draine
     writes.map((line) => JSON.parse(line).command),
     [
       ['set_property', 'pause', true],
-      ['seek', 12.25, 'absolute+exact'],
       ['set_property', 'end', '14.500'],
+      ['seek', 12.25, 'absolute+exact'],
       ['set_property', 'pause', false],
     ],
   );

src/core/services/media-timing-preview.ts

@@ -15,6 +15,8 @@ const CONNECT_RETRY_MS = 40;
  */
 const EOF_OBSERVER_ID = 1;
 const PAUSE_OBSERVER_ID = 2;
+const POSITION_OBSERVER_ID = 3;
+const PLAYER_RESPONSE_TIMEOUT_MS = 15_000;
 
 export interface MediaTimingPreviewStartOptions {
   mediaPath: string;
@@ -23,6 +25,7 @@ export interface MediaTimingPreviewStartOptions {
   volume?: number;
   /** The file keeps source timestamps (a cached remote window); seek with the original times. */
   absoluteTimestamps?: boolean;
+  onPlaybackPosition?: (time: number) => void;
 }
 
 type PreviewProcess = Pick<ChildProcess, 'kill' | 'once'>;
@@ -103,8 +106,21 @@ export class MediaTimingPreviewSession {
   private disposed = false;
   private readBuffer = '';
   private playing = false;
+  private playSequence = 0;
   private eofReached = false;
   private paused = true;
+  private mediaReady = false;
+  private onPlaybackPosition: MediaTimingPreviewStartOptions['onPlaybackPosition'];
+  private nextRequestId = 0;
+  private readonly pendingCommands = new Map<
+    number,
+    {
+      resolve: () => void;
+      reject: (error: Error) => void;
+    }
+  >();
+  private readonly readyListeners = new Set<() => void>();
+  private readonly pendingWaits = new Set<(error: Error) => void>();
   private readonly endedListeners = new Set<() => void>();
 
   constructor(deps: Partial<MediaTimingPreviewDeps> = {}) {
@@ -141,6 +157,8 @@ export class MediaTimingPreviewSession {
   private async startOnce(options: MediaTimingPreviewStartOptions): Promise<void> {
     const mediaPath = options.mediaPath.trim();
     if (!mediaPath) throw new Error('No media source is available for preview');
+    this.mediaReady = false;
+    this.onPlaybackPosition = options.onPlaybackPosition;
 
     const socketPath = this.deps.createSocketPath();
     this.socketPath = socketPath;
@@ -186,19 +204,35 @@ export class MediaTimingPreviewSession {
     }
 
     this.playing = false;
-    this.send(['set_property', 'pause', true]);
-    this.send(['seek', startTime, 'absolute+exact']);
+    const sequence = ++this.playSequence;
+    if (!this.mediaReady) {
+      await this.waitForPlayer((resolve) => {
+        this.readyListeners.add(resolve);
+        return () => this.readyListeners.delete(resolve);
+      });
+    }
     // The option parser wants a time string; a raw JSON number is not accepted for `end`.
-    this.send(['set_property', 'end', endTime.toFixed(3)]);
-    this.send(['set_property', 'pause', false]);
-    // Only the seek's eof-reached=false and the later keep-open pause count for this play.
+    const commands = [
+      ['set_property', 'pause', true],
+      ['set_property', 'end', endTime.toFixed(3)],
+      ['seek', startTime, 'absolute+exact'],
+      ['set_property', 'pause', false],
+    ];
+    for (const command of commands) {
+      if (sequence !== this.playSequence) throw new Error('Preview playback was cancelled');
+      await this.command(command);
+    }
+    if (sequence !== this.playSequence) throw new Error('Preview playback was cancelled');
+    // Discard paused/EOF observations from the previous clip before arming this playback.
     this.eofReached = false;
     this.paused = false;
     this.playing = true;
   }
 
   async stop(): Promise<void> {
+    this.playSequence += 1;
     this.playing = false;
+    this.rejectPendingWaits();
     if (!this.socket || this.socket.destroyed) return;
     this.send(['set_property', 'pause', true]);
   }
@@ -227,6 +261,23 @@ export class MediaTimingPreviewSession {
       } catch {
         continue;
       }
+      if (
+        typeof message === 'object' &&
+        message !== null &&
+        'request_id' in message &&
+        typeof message.request_id === 'number'
+      ) {
+        const pending = this.pendingCommands.get(message.request_id);
+        if (pending) {
+          if ('error' in message && message.error === 'success') pending.resolve();
+          else
+            pending.reject(
+              new Error(
+                `Preview command failed: ${'error' in message ? String(message.error) : 'unknown error'}`,
+              ),
+            );
+        }
+      }
       if (
         typeof message === 'object' &&
         message !== null &&
@@ -241,6 +292,13 @@ export class MediaTimingPreviewSession {
   }
 
   private handlePropertyChange(name: unknown, data: unknown): void {
+    if (name === 'time-pos') {
+      if (typeof data !== 'number' || !Number.isFinite(data)) return;
+      this.mediaReady = true;
+      for (const listener of this.readyListeners) listener();
+      if (this.playing) this.onPlaybackPosition?.(data);
+      return;
+    }
     if (name === 'eof-reached') this.eofReached = data === true;
     else if (name === 'pause') this.paused = data === true;
     else return;
@@ -255,6 +313,8 @@ export class MediaTimingPreviewSession {
 
   private releaseResources(): void {
     this.cancelRetryWait();
+    this.playing = false;
+    this.rejectPendingWaits();
     try {
       this.send(['quit']);
     } catch {
@@ -283,6 +343,57 @@ export class MediaTimingPreviewSession {
     this.socket.write(`${JSON.stringify({ command })}\n`);
   }
 
+  private waitForPlayer(
+    subscribe: (resolve: () => void, reject: (error: Error) => void) => () => void,
+  ): Promise<void> {
+    return new Promise((resolve, reject) => {
+      let settled = false;
+      let unsubscribe = () => {};
+      const finish = (error?: Error) => {
+        if (settled) return;
+        settled = true;
+        this.deps.cancelSchedule(timeout);
+        unsubscribe();
+        this.pendingWaits.delete(fail);
+        if (error) reject(error);
+        else resolve();
+      };
+      const fail = (error: Error) => finish(error);
+      const timeout = this.deps.schedule(
+        () => fail(new Error('Timed out waiting for the preview player')),
+        PLAYER_RESPONSE_TIMEOUT_MS,
+      );
+      this.pendingWaits.add(fail);
+      try {
+        unsubscribe = subscribe(() => finish(), fail);
+        if (settled) unsubscribe();
+      } catch (error) {
+        fail(error instanceof Error ? error : new Error(String(error)));
+      }
+    });
+  }
+
+  private command(command: Array<string | number | boolean>): Promise<void> {
+    if (!this.socket || this.socket.destroyed)
+      return Promise.reject(new Error('Preview player is not ready'));
+    const socket = this.socket;
+    const requestId = ++this.nextRequestId;
+    return this.waitForPlayer((resolve, reject) => {
+      this.pendingCommands.set(requestId, { resolve, reject });
+      try {
+        socket.write(`${JSON.stringify({ command, request_id: requestId })}\n`);
+      } catch (error) {
+        this.pendingCommands.delete(requestId);
+        throw error;
+      }
+      return () => this.pendingCommands.delete(requestId);
+    });
+  }
+
+  private rejectPendingWaits(): void {
+    for (const reject of this.pendingWaits) reject(new Error('Preview player is closed'));
+  }
+
   private async connectWithRetry(socketPath: string): Promise<void> {
     const deadline = this.deps.now() + CONNECT_TIMEOUT_MS;
     while (!this.disposed && this.deps.now() < deadline) {
@@ -305,9 +416,13 @@ export class MediaTimingPreviewSession {
         socket.on('data', (chunk: Buffer | string) => {
           if (this.socket === socket) this.handleSocketData(chunk);
         });
-        socket.once('close', () => this.finishPlayback());
+        socket.once('close', () => {
+          this.rejectPendingWaits();
+          this.finishPlayback();
+        });
         this.send(['observe_property', EOF_OBSERVER_ID, 'eof-reached']);
         this.send(['observe_property', PAUSE_OBSERVER_ID, 'pause']);
+        this.send(['observe_property', POSITION_OBSERVER_ID, 'time-pos']);
         return;
       } catch {
         if (this.disposed) {

src/main.ts

@@ -3009,6 +3009,13 @@ const mediaTimingReviewRuntime = createMediaTimingReviewRuntime({
       }
     }
   },
+  onPreviewPosition: (position) => {
+    for (const window of [overlayManager.getMainWindow(), overlayManager.getModalWindow()]) {
+      if (window && !window.isDestroyed()) {
+        window.webContents.send(IPC_CHANNELS.event.mediaTimingReviewPreviewPosition, position);
+      }
+    }
+  },
   showStatus: (message) =>
     overlayNotificationsRuntime.showConfiguredStatusNotification(message, { variant: 'warning' }),
 });

src/main/runtime/media-timing-review.test.ts

@@ -410,14 +410,17 @@ test('media timing review downloads one window of a remote stream for the wavefo
       endTime: 14.5,
     },
   ]);
-  assert.deepEqual(previewStarts, [
-    {
-      mediaPath: '/tmp/window-7.5-14.5.mkv',
-      executablePath: 'mpv',
-      volume: 60,
-      absoluteTimestamps: true,
-    },
-  ]);
+  assert.deepEqual(
+    previewStarts.map(({ onPlaybackPosition, ...options }) => options),
+    [
+      {
+        mediaPath: '/tmp/window-7.5-14.5.mkv',
+        executablePath: 'mpv',
+        volume: 60,
+        absoluteTimestamps: true,
+      },
+    ],
+  );
   assert.deepEqual(previewPlays, [['/tmp/window-7.5-14.5.mkv', 9.5, 12.5]]);
   assert.deepEqual(disposed, ['/tmp/window-7.5-14.5.mkv']);
 });
@@ -512,9 +515,10 @@ test('media timing review falls back to the remote stream after one failed windo
       audioStreamIndex: 2,
     },
   ]);
-  assert.deepEqual(previewStarts, [
-    { mediaPath: REMOTE_STREAM_URL, executablePath: 'mpv', volume: 60, audioTrackId: 3 },
-  ]);
+  assert.deepEqual(
+    previewStarts.map(({ onPlaybackPosition, ...options }) => options),
+    [{ mediaPath: REMOTE_STREAM_URL, executablePath: 'mpv', volume: 60, audioTrackId: 3 }],
+  );
   assert.deepEqual(previewPlays, [[REMOTE_STREAM_URL, 9.5, 12.5]]);
 });
 
@@ -981,7 +985,8 @@ test('disposing owns a preview session whose startup is still pending', async ()
 
 test('media timing review forwards the hidden player finishing a preview to the modal', async () => {
   const endedReviewIds: string[] = [];
-  const playback: { ended?: () => void } = {};
+  const positions: Array<{ reviewId: string; time: number }> = [];
+  const playback: { ended?: () => void; position?: (time: number) => void } = {};
   let publishPayload!: (payload: MediaTimingReviewOpenPayload) => void;
   const openedPayload = new Promise<MediaTimingReviewOpenPayload>((resolve) => {
     publishPayload = resolve;
@@ -997,7 +1002,9 @@ test('media timing review forwards the hidden player finishing a preview to the
     getMpvExecutablePath: () => 'mpv',
     generateWaveform: async () => [],
     createPreviewSession: () => ({
-      start: async () => undefined,
+      start: async (options) => {
+        playback.position = options.onPlaybackPosition;
+      },
       play: async () => undefined,
       stop: async () => undefined,
       onPlaybackEnded: (listener) => {
@@ -1012,6 +1019,7 @@ test('media timing review forwards the hidden player finishing a preview to the
     onPreviewEnded: (reviewId) => {
       endedReviewIds.push(reviewId);
     },
+    onPreviewPosition: (position) => positions.push(position),
     showStatus: () => undefined,
   });
   const pendingDecision = runtime.requestReview({
@@ -1031,6 +1039,9 @@ test('media timing review forwards the hidden player finishing a preview to the
     },
   );
   assert.ok(playback.ended);
+  assert.ok(playback.position);
+  playback.position(11);
+  assert.deepEqual(positions, [{ reviewId: payload.reviewId, time: 11 }]);
   playback.ended();
   assert.deepEqual(endedReviewIds, [payload.reviewId]);
 
@@ -1038,6 +1049,8 @@ test('media timing review forwards the hidden player finishing a preview to the
   await pendingDecision;
   playback.ended();
   assert.deepEqual(endedReviewIds, [payload.reviewId]);
+  playback.position(12);
+  assert.deepEqual(positions, [{ reviewId: payload.reviewId, time: 11 }]);
 });
 
 test('preview reports a stale review when the review ends during playback', async () => {

src/main/runtime/media-timing-review.ts

@@ -5,6 +5,7 @@ import type {
   MediaTimingReviewDecision,
   MediaTimingReviewOpenPayload,
   MediaTimingReviewPreviewRequest,
+  MediaTimingReviewPreviewPosition,
   MediaTimingReviewRequest,
   MediaTimingReviewResolveRequest,
   MediaTimingReviewFrameRequest,
@@ -13,6 +14,7 @@ import type {
   MediaTimingReviewWaveformResult,
 } from '../../types/anki';
 import type { SpeechWaveformOptions } from '../../core/services/media-timing-waveform';
+import type { MediaTimingPreviewStartOptions } from '../../core/services/media-timing-preview';
 import type { MediaTimingFrameOptions } from '../../core/services/media-timing-frame';
 import {
   isRemoteMediaWindowSourcePath,
@@ -36,13 +38,7 @@ interface ReviewMpvClient {
 }
 
 interface PreviewSession {
-  start(options: {
-    mediaPath: string;
-    executablePath?: string;
-    audioTrackId?: number;
-    volume?: number;
-    absoluteTimestamps?: boolean;
-  }): Promise<void>;
+  start(options: MediaTimingPreviewStartOptions): Promise<void>;
   play(startTime: number, endTime: number): Promise<void>;
   stop(): Promise<void>;
   /** Fires when the player reaches the end of the clip started by play(). */
@@ -113,6 +109,7 @@ export interface MediaTimingReviewRuntimeDeps {
   openModal: (payload: MediaTimingReviewOpenPayload, signal: AbortSignal) => Promise<boolean>;
   /** Tells the modal that the hidden player finished the previewed clip. */
   onPreviewEnded?: (reviewId: string) => void;
+  onPreviewPosition?: (position: MediaTimingReviewPreviewPosition) => void;
   showStatus: (message: string) => void;
 }
 
@@ -354,6 +351,11 @@ export function createMediaTimingReviewRuntime(deps: MediaTimingReviewRuntimeDep
       }
       await session.start({
         mediaPath,
+        onPlaybackPosition: (time) => {
+          if (active === review && review.preview?.session === started) {
+            deps.onPreviewPosition?.({ reviewId: review.payload.reviewId, time });
+          }
+        },
         ...previewOptions,
         // A cached window keeps one audio stream, so mpv's track id from the source no longer applies.
         ...(window

src/preload.ts

@@ -71,6 +71,7 @@ import type {
   ChangelogSnapshot,
   MediaTimingReviewActionResult,
   MediaTimingReviewOpenPayload,
+  MediaTimingReviewPreviewPosition,
   MediaTimingReviewPreviewRequest,
   MediaTimingReviewResolveRequest,
   MediaTimingReviewFrameRequest,
@@ -511,6 +512,26 @@ const electronAPI: ElectronAPI = {
   onOpenYoutubeTrackPicker: onOpenYoutubeTrackPickerEvent,
   onOpenMediaTimingReview: onOpenMediaTimingReviewEvent,
   onMediaTimingReviewPreviewEnded: onMediaTimingReviewPreviewEndedEvent,
+  onMediaTimingReviewPreviewPosition: (
+    callback: (position: MediaTimingReviewPreviewPosition) => void,
+  ): void => {
+    ipcRenderer.on(
+      IPC_CHANNELS.event.mediaTimingReviewPreviewPosition,
+      (_event, payload: unknown) => {
+        if (
+          typeof payload !== 'object' ||
+          payload === null ||
+          !('reviewId' in payload) ||
+          typeof payload.reviewId !== 'string' ||
+          !('time' in payload) ||
+          typeof payload.time !== 'number' ||
+          !Number.isFinite(payload.time)
+        )
+          return;
+        callback({ reviewId: payload.reviewId, time: payload.time });
+      },
+    );
+  },
   previewMediaTimingReview: (
     request: MediaTimingReviewPreviewRequest,
   ): Promise<MediaTimingReviewActionResult> =>

src/renderer/modals/media-timing-review.ts

@@ -3,6 +3,7 @@ import type {
   MediaTimingReviewContextLine,
   MediaTimingReviewDecision,
   MediaTimingReviewOpenPayload,
+  MediaTimingReviewPreviewPosition,
 } from '../../types/anki';
 import type { ModalStateReader, RendererContext } from '../context';
 import { createModalFocusGuard } from './modal-focus-guard';
@@ -20,8 +21,8 @@ const LINE_REVEAL_MARGIN_SECONDS = 1;
 const SPEECH_LEVEL_THRESHOLD = 0.3;
 const SPEECH_TAIL_SECONDS = 0.15;
 const MINIMUM_TRAILING_TRIM_SECONDS = 0.1;
-/** Slack past the clip length before the UI gives up waiting for mpv's end-of-clip signal. */
-const PREVIEW_END_GRACE_MS = 2_500;
+/** Allow buffering and output-device delays without cutting off an advancing preview. */
+const PREVIEW_STALL_TIMEOUT_MS = 15_000;
 
 function clamp(value: number, minimum: number, maximum: number): number {
   return Math.min(maximum, Math.max(minimum, value));
@@ -303,30 +304,49 @@ export function createMediaTimingReviewModal(
     previewTimer = null;
   }
 
-  /**
-   * Drives the play button label plus the playhead sweep that mirrors the hidden audio player.
-   * mpv reports when the clip actually finishes (see handlePreviewEnded), which accounts for
-   * output latency such as Bluetooth headphones; the timer only covers a player that never does.
-   */
-  function setPreviewPlaying(playing: boolean): void {
+  function armPreviewTimeout(): void {
+    clearPreviewTimer();
+    previewTimer = setTimeout(() => {
+      stopPreview();
+      setStatus('Audio preview stopped responding. Try playing the selection again.', true);
+    }, PREVIEW_STALL_TIMEOUT_MS);
+  }
+
+  /** Playback position comes from mpv, so stalls and output latency cannot outrun the cursor. */
+  function setPreviewPlaying(playing: boolean, finished = false): void {
     previewPlaying = playing;
     ctx.dom.mediaTimingReviewPlayLabel.textContent = playing ? 'Stop preview' : 'Play selection';
     ctx.dom.mediaTimingReviewPlay.classList.toggle('is-playing', playing);
     clearPreviewTimer();
     const track = ctx.dom.mediaTimingReviewSelectionTrack;
-    track.classList.remove('is-previewing');
+    track.classList.toggle('is-previewing', playing || finished);
+    if (finished) track.style.setProperty('--playhead-position', 'var(--selection-end)');
     if (!playing) return;
-    const clipSeconds = Math.max(MINIMUM_CLIP_SECONDS, selectionEnd - selectionStart);
-    track.style.setProperty('--playhead-duration', `${clipSeconds}s`);
-    void track.offsetWidth;
-    track.classList.add('is-previewing');
-    previewTimer = setTimeout(() => stopPreview(), clipSeconds * 1000 + PREVIEW_END_GRACE_MS);
+    track.style.setProperty('--playhead-position', 'var(--selection-start)');
+    armPreviewTimeout();
+  }
+
+  function handlePreviewPosition(position: MediaTimingReviewPreviewPosition): void {
+    if (
+      !payload ||
+      payload.reviewId !== position.reviewId ||
+      !previewPlaying ||
+      !Number.isFinite(position.time)
+    )
+      return;
+    const time = clamp(position.time, selectionStart, selectionEnd);
+    const span = Math.max(MINIMUM_CLIP_SECONDS, timelineEnd - timelineStart);
+    ctx.dom.mediaTimingReviewSelectionTrack.style.setProperty(
+      '--playhead-position',
+      `${clamp(((time - timelineStart) / span) * 100, 0, 100)}%`,
+    );
+    armPreviewTimeout();
   }
 
   /** The hidden player reached the end of the clip and paused itself. */
   function handlePreviewEnded(reviewId: string): void {
     if (!payload || payload.reviewId !== reviewId || !previewPlaying) return;
-    setPreviewPlaying(false);
+    setPreviewPlaying(false, true);
     setStatus('');
   }
 
@@ -1026,6 +1046,7 @@ export function createMediaTimingReviewModal(
   return {
     openMediaTimingReviewModal,
     handlePreviewEnded,
+    handlePreviewPosition,
     requestCancel,
     handleMediaTimingReviewKeydown,
     wireDomEvents,

src/renderer/renderer.ts

@@ -625,6 +625,9 @@ function registerModalOpenHandlers(): void {
       mediaTimingReviewModal.handlePreviewEnded(reviewId);
     });
   });
+  window.electronAPI.onMediaTimingReviewPreviewPosition((position) => {
+    mediaTimingReviewModal.handlePreviewPosition(position);
+  });
   window.electronAPI.onOpenPlaylistBrowser(() => {
     runGuardedAsync('playlist-browser:open', async () => {
       await playlistBrowserModal.openPlaylistBrowserModal();

src/renderer/style.css

@@ -1687,7 +1687,7 @@ body:focus-visible,
   --selection-end: 80%;
   --original-start: 25%;
   --original-end: 75%;
-  --playhead-duration: 1s;
+  --playhead-position: var(--selection-start);
 
   position: relative;
   height: 52px;
@@ -1803,10 +1803,10 @@ body:focus-visible,
 
 .media-timing-review-playhead {
   position: absolute;
-  z-index: 5;
+  z-index: 7;
   top: 0;
   bottom: 0;
-  left: var(--selection-start);
+  left: clamp(0px, var(--playhead-position), calc(100% - 2px));
   width: 2px;
   background: var(--ctp-yellow);
   box-shadow: 0 0 12px color-mix(in srgb, var(--ctp-yellow) 75%, transparent);
@@ -1816,16 +1816,6 @@ body:focus-visible,
 
 .media-timing-review-track.is-previewing .media-timing-review-playhead {
   opacity: 1;
-  animation: media-timing-review-playhead var(--playhead-duration) linear forwards;
-}
-
-@keyframes media-timing-review-playhead {
-  from {
-    left: var(--selection-start);
-  }
-  to {
-    left: var(--selection-end);
-  }
 }
 
 /* A thin line centered on the clip edge, so the line itself is the trim boundary. */
@@ -2128,8 +2118,7 @@ body:focus-visible,
     animation: none;
   }
 
-  .media-timing-review-track.is-loading::after,
-  .media-timing-review-track.is-previewing .media-timing-review-playhead {
+  .media-timing-review-track.is-loading::after {
     animation: none;
   }
 }

src/shared/ipc/contracts.ts

@@ -167,6 +167,7 @@ export const IPC_CHANNELS = {
     youtubePickerOpen: 'youtube:picker-open',
     mediaTimingReviewOpen: 'media-timing-review:open',
     mediaTimingReviewPreviewEnded: 'media-timing-review:preview-ended',
+    mediaTimingReviewPreviewPosition: 'media-timing-review:preview-position',
     youtubePickerCancel: 'youtube:picker-cancel',
     playlistBrowserOpen: 'playlist-browser:open',
     sessionNumericSelectionStart: 'session:numeric-selection-start',

src/types/anki.ts

@@ -82,6 +82,11 @@ export interface MediaTimingReviewPreviewRequest {
   endTime: number;
 }
 
+export interface MediaTimingReviewPreviewPosition {
+  reviewId: string;
+  time: number;
+}
+
 export interface MediaTimingReviewWaveformRequest {
   reviewId: string;
   startTime: number;

src/types/runtime.ts

@@ -6,6 +6,7 @@ import type {
   KikuMergePreviewResponse,
   MediaTimingReviewActionResult,
   MediaTimingReviewOpenPayload,
+  MediaTimingReviewPreviewPosition,
   MediaTimingReviewPreviewRequest,
   MediaTimingReviewResolveRequest,
   MediaTimingReviewFrameRequest,
@@ -556,6 +557,9 @@ export interface ElectronAPI {
   onOpenYoutubeTrackPicker: (callback: (payload: YoutubePickerOpenPayload) => void) => void;
   onOpenMediaTimingReview: (callback: (payload: MediaTimingReviewOpenPayload) => void) => void;
   onMediaTimingReviewPreviewEnded: (callback: (reviewId: string) => void) => void;
+  onMediaTimingReviewPreviewPosition: (
+    callback: (position: MediaTimingReviewPreviewPosition) => void,
+  ) => void;
   previewMediaTimingReview: (
     request: MediaTimingReviewPreviewRequest,
   ) => Promise<MediaTimingReviewActionResult>;