fix(subtitles): follow sub-delay in sidebar, navigation, and overlay matching

Anything comparing time-pos with parsed cues now converts through a
shared subtitle-clock helper: the sidebar highlight and click-to-seek,
the sub-seek cue sanitizer, overlay/primer line resolution, and the
replay pause point after sub-seek.

changes/mining-respects-sub-delay.md

@@ -1,4 +1,4 @@
 type: fixed
-area: anki
+area: subtitles
 
-- Mined card audio, images, and timestamps now follow mpv's manual subtitle retiming (`sub-delay`, z/x), instead of clipping the subtitle file's original timing.
+- mpv's manual subtitle retiming (`sub-delay`, z/x and sub-step) now carries through SubMiner: mined card audio, images, and timestamps clip the retimed line, and the subtitle sidebar highlight, click-to-seek, subtitle navigation, overlay line matching, and replay pause point all follow the retimed timing.

e2e/playback.e2e.test.ts

@@ -224,6 +224,49 @@ test(
   },
 );
 
+test(
+  'subtitle sidebar follows and seeks a sub-delay retimed track',
+  { timeout: TEST_TIMEOUT_MS },
+  async () => {
+    const { session, overlay } = await useSession();
+    const delay = 2;
+    await session.mpv.command('set_property', 'sub-delay', delay);
+    try {
+      // At 9s cue 2 starts on the file's clock, but mpv is still showing cue 1.
+      await session.mpv.command('seek', FIXTURE_CUES[2].start, 'absolute+exact');
+      await overlay.waitFor(
+        `document.getElementById('subtitleRoot').textContent === ${JSON.stringify(FIXTURE_CUES[1].text)}`,
+        { description: 'overlay to show the delayed line' },
+      );
+      await session.runAppCommand('--toggle-subtitle-sidebar');
+      await overlay.waitFor(
+        `document.querySelector('#subtitleSidebarList .subtitle-sidebar-item.active')?.dataset.index === '1'`,
+        { description: 'sidebar to highlight the delayed line' },
+      );
+
+      await overlay.evaluate(
+        `document.querySelector('#subtitleSidebarList .subtitle-sidebar-item[data-index="2"]').click()`,
+      );
+      const target = FIXTURE_CUES[2].start + delay;
+      await waitUntil(
+        async () => {
+          const time = Number(await session.mpv.command('get_property', 'time-pos'));
+          return time >= target && time < target + 0.5;
+        },
+        { description: `click to seek to cue 2 at ${target}s on the video clock` },
+      );
+
+      await session.runAppCommand('--toggle-subtitle-sidebar');
+      await overlay.waitFor(
+        `document.getElementById('subtitleSidebarModal').classList.contains('hidden')`,
+        { description: 'sidebar to close' },
+      );
+    } finally {
+      await session.mpv.command('set_property', 'sub-delay', 0);
+    }
+  },
+);
+
 // Runs last: it leaves the lookup popup open over the overlay.
 test(
   'holding Shift over a word opens the Yomitan popup with its dictionary entry',

src/anki-integration.ts

@@ -44,10 +44,8 @@ import {
   getPreferredWordValueFromExtractedFields,
 } from './anki-field-config';
 import { createLogger } from './logger';
-import {
+import { captureLiveSubtitleMiningContext } from './core/services/mining';
-  captureLiveSubtitleMiningContext,
+import { shiftSubtitleRangeToVideoClock } from './core/services/subtitle-clock';
-  shiftSubtitleRangeToVideoClock,
-} from './core/services/mining';
 import {
   createUiFeedbackState,
   beginUpdateProgress,

src/anki-integration/card-creation.ts

@@ -10,7 +10,7 @@ import {
   type MediaTimingReviewRequest,
   type WordCardKind,
 } from '../types/anki';
-import { shiftSubtitleRangeToVideoClock } from '../core/services/mining';
+import { shiftSubtitleRangeToVideoClock } from '../core/services/subtitle-clock';
 import { createLogger } from '../logger';
 import type { MediaInput } from '../media-input';
 import { SubtitleTimingTracker } from '../subtitle-timing-tracker';

src/core/services/index.ts

@@ -22,7 +22,6 @@ export {
   handleMultiCopyDigit,
   markLastCardAsAudioCard,
   mineSentenceCard,
-  shiftSubtitleRangeToVideoClock,
   triggerFieldGrouping,
   updateLastCardFromClipboard,
 } from './mining';
@@ -56,6 +55,7 @@ export {
   subtitleCueListSeekTime,
   subtitleCueSeekTime,
 } from './subtitle-cue-navigation';
+export { shiftSubtitleRangeToVideoClock, toSubtitleClock, toVideoClock } from './subtitle-clock';
 export { createFrequencyDictionaryLookup } from './frequency-dictionary';
 export { createJlptVocabularyLookup } from './jlpt-vocab';
 export {

src/core/services/ipc.test.ts

@@ -89,6 +89,7 @@ function createSubtitleSidebarSnapshotFixture(): SubtitleSidebarSnapshot {
     cuesRevision: 1,
     cues: [],
     currentTimeSec: null,
+    subDelay: 0,
     currentSubtitle: { text: '', startTime: null, endTime: null },
     config: {
       enabled: false,

src/core/services/mining.ts

@@ -1,5 +1,6 @@
 import type { SubtitleTimingBlock } from '../../subtitle-timing-tracker';
 import type { SubtitleMiningContext } from '../../types/subtitle';
+import { shiftSubtitleRangeToVideoClock } from './subtitle-clock';
 
 interface SubtitleTimingTrackerLike {
   getRecentBlocks: (count: number) => string[];
@@ -56,21 +57,6 @@ export function handleMultiCopyDigit(
   }
 }
 
-/**
- * mpv's `sub-start`/`sub-end` and parsed cues carry the subtitle file's own timestamps,
- * but mpv plays each line `sub-delay` seconds later (z/x retiming). Media is cut from the
- * video, so subtitle timings move onto the video clock before they reach mining.
- */
-export function shiftSubtitleRangeToVideoClock<T extends { startTime: number; endTime: number }>(
-  range: T,
-  subDelay: number,
-): T {
-  if (!Number.isFinite(subDelay) || subDelay === 0) {
-    return range;
-  }
-  return { ...range, startTime: range.startTime + subDelay, endTime: range.endTime + subDelay };
-}
-
 /**
  * Snapshot the live mpv subtitle line and its timings as a mining context. Media
  * generation can run tens of seconds after the user mines (slow audio extraction),

src/core/services/mpv-protocol.test.ts

@@ -74,6 +74,7 @@ function createDeps(overrides: Partial<MpvProtocolHandleMessageDeps> = {}): {
       setCurrentSubEnd: () => {},
       getCurrentSubEnd: () => 0,
       setCurrentSubDelay: () => {},
+      getCurrentSubDelay: () => 0,
       emitMediaPathChange: (payload) => {
         state.mediaPath = payload.path;
       },
@@ -396,6 +397,21 @@ test('dispatchMpvProtocolMessage pauses on sub-end when pendingPauseAtSubEnd is
   });
 });
 
+test('dispatchMpvProtocolMessage pauses at the sub-delay retimed sub-end', async () => {
+  let pauseAtTime: number | null = null;
+  const { deps } = createDeps({
+    getPendingPauseAtSubEnd: () => true,
+    getCurrentSubDelay: () => 1.5,
+    setPauseAtTime: (next) => {
+      pauseAtTime = next;
+    },
+  });
+
+  await dispatchMpvProtocolMessage({ event: 'property-change', name: 'sub-end', data: 42 }, deps);
+
+  assert.equal(pauseAtTime, 43.5);
+});
+
 test('dispatchMpvProtocolMessage updates current time before emitting time-pos change', async () => {
   const calls: string[] = [];
   let currentTimePos = 0;

src/core/services/mpv-protocol.ts

@@ -1,6 +1,7 @@
 import { MpvSubtitleRenderMetrics } from '../../types';
 import { sanitizeMediaTitle } from '../../shared/media-identity';
 import { widenHalfwidthKana } from '../utils/halfwidth-kana';
+import { toVideoClock } from './subtitle-clock';
 
 export type MpvMessage = {
   event?: string;
@@ -65,6 +66,7 @@ export interface MpvProtocolHandleMessageDeps {
   setCurrentSubEnd: (value: number) => void;
   getCurrentSubEnd: () => number;
   setCurrentSubDelay: (value: number) => void;
+  getCurrentSubDelay: () => number;
   emitMediaPathChange: (payload: { path: string }) => void;
   emitMediaTitleChange: (payload: { title: string | null }) => void;
   emitTimePosChange: (payload: { time: number }) => void;
@@ -264,7 +266,8 @@ export async function dispatchMpvProtocolMessage(
       const subEnd = (msg.data as number) || 0;
       deps.setCurrentSubEnd(subEnd);
       if (deps.getPendingPauseAtSubEnd() && subEnd > 0) {
-        deps.setPauseAtTime(subEnd);
+        // `sub-end` is on the subtitle clock; the pause check compares it with `time-pos`.
+        deps.setPauseAtTime(toVideoClock(subEnd, deps.getCurrentSubDelay()));
         deps.setPendingPauseAtSubEnd(false);
         deps.sendCommand({ command: ['set_property', 'pause', false] });
       }

src/core/services/mpv.ts

@@ -464,6 +464,7 @@ export class MpvIpcClient implements MpvClient {
       setCurrentSubDelay: (value: number) => {
         this.currentSubDelay = value;
       },
+      getCurrentSubDelay: () => this.currentSubDelay,
       emitMediaPathChange: (payload) => {
         this.emit('media-path-change', payload);
       },

src/core/services/subtitle-clock.ts

@@ -0,0 +1,32 @@
+/**
+ * mpv's `sub-start`/`sub-end` and parsed cues carry the subtitle file's own timestamps
+ * (the subtitle clock), but mpv plays each line `sub-delay` seconds later (z/x retiming,
+ * `sub-step`). Playback position, seeks, and media cuts are on the video clock, so any
+ * value crossing between the two converts here.
+ */
+
+function finiteDelay(subDelay: number): number {
+  return Number.isFinite(subDelay) ? subDelay : 0;
+}
+
+/** Playback position (`time-pos`) on the subtitle clock, comparable with cue times. */
+export function toSubtitleClock(videoTimeSec: number, subDelay: number): number {
+  return videoTimeSec - finiteDelay(subDelay);
+}
+
+/** Subtitle-clock seconds on the video clock, for seeks. */
+export function toVideoClock(subtitleTimeSec: number, subDelay: number): number {
+  return subtitleTimeSec + finiteDelay(subDelay);
+}
+
+/** A subtitle-clock range on the video clock, for mining and media generation. */
+export function shiftSubtitleRangeToVideoClock<T extends { startTime: number; endTime: number }>(
+  range: T,
+  subDelay: number,
+): T {
+  const delay = finiteDelay(subDelay);
+  if (delay === 0) {
+    return range;
+  }
+  return { ...range, startTime: range.startTime + delay, endTime: range.endTime + delay };
+}

src/core/services/subtitle-cue-navigation.test.ts

@@ -26,7 +26,7 @@ test('next subtitle navigation skips generated ASS events and seeks to the next
     },
   ];
 
-  assert.deepEqual(resolveSanitizedSubtitleSeekCommand(['sub-seek', 1], cues, 10.2), [
+  assert.deepEqual(resolveSanitizedSubtitleSeekCommand(['sub-seek', 1], cues, 10.2, 0), [
     'seek',
     13.08,
     'absolute+exact',
@@ -41,7 +41,7 @@ test('next subtitle navigation treats simultaneous sanitized cues as one line bo
     { startTime: 13.02, endTime: 16, text: 'Next English' },
   ];
 
-  assert.deepEqual(resolveSanitizedSubtitleSeekCommand(['sub-seek', 1], cues, 10.1), [
+  assert.deepEqual(resolveSanitizedSubtitleSeekCommand(['sub-seek', 1], cues, 10.1, 0), [
     'seek',
     13.08,
     'absolute+exact',
@@ -55,7 +55,7 @@ test('next subtitle navigation advances past the latest overlapping lyric', () =
     { startTime: 16, endTime: 19, text: 'next lyric' },
   ];
 
-  assert.deepEqual(resolveSanitizedSubtitleSeekCommand(['sub-seek', 1], cues, 13.2), [
+  assert.deepEqual(resolveSanitizedSubtitleSeekCommand(['sub-seek', 1], cues, 13.2, 0), [
     'seek',
     16.08,
     'absolute+exact',
@@ -68,7 +68,7 @@ test('previous subtitle navigation leaves the current cue and seeks to the prior
     { startTime: 13, endTime: 16, text: 'current line' },
   ];
 
-  assert.deepEqual(resolveSanitizedSubtitleSeekCommand(['sub-seek', -1], cues, 14.5), [
+  assert.deepEqual(resolveSanitizedSubtitleSeekCommand(['sub-seek', -1], cues, 14.5, 0), [
     'seek',
     10.08,
     'absolute+exact',
@@ -78,8 +78,22 @@ test('previous subtitle navigation leaves the current cue and seeks to the prior
 test('subtitle navigation falls back when no sanitized destination exists', () => {
   const cues = [{ startTime: 10, endTime: 13, text: 'only line' }];
 
-  assert.equal(resolveSanitizedSubtitleSeekCommand(['sub-seek', 1], cues, 10.2), null);
+  assert.equal(resolveSanitizedSubtitleSeekCommand(['sub-seek', 1], cues, 10.2, 0), null);
-  assert.equal(resolveSanitizedSubtitleSeekCommand(['seek', 5], cues, 10.2), null);
+  assert.equal(resolveSanitizedSubtitleSeekCommand(['seek', 5], cues, 10.2, 0), null);
+});
+
+test('subtitle cue navigation finds and seeks cues on the sub-delay retimed timeline', () => {
+  const cues = [
+    { startTime: 10, endTime: 13, text: 'one' },
+    { startTime: 13, endTime: 16, text: 'two' },
+  ];
+
+  // At 14.5 with a 2s delay, mpv is showing "one" (12-15 on the video clock).
+  assert.deepEqual(resolveSanitizedSubtitleSeekCommand(['sub-seek', 1], cues, 14.5, 2), [
+    'seek',
+    15.08,
+    'absolute+exact',
+  ]);
 });
 
 test('sidebar cue seeks share the boundary-safe sanitized cue timestamp', () => {

src/core/services/subtitle-cue-navigation.ts

@@ -1,3 +1,4 @@
+import { toSubtitleClock, toVideoClock } from './subtitle-clock';
 import type { SubtitleCue } from './subtitle-cue-parser';
 
 const CUE_START_GROUP_TOLERANCE_SECONDS = 0.05;
@@ -80,8 +81,10 @@ export function subtitleCueListSeekTime(
 export function resolveSanitizedSubtitleSeekCommand(
   command: readonly (string | number)[],
   cues: readonly SubtitleCue[],
-  currentTimeSec: number,
+  videoTimeSec: number,
+  subDelay: number,
 ): (string | number)[] | null {
+  const currentTimeSec = toSubtitleClock(videoTimeSec, subDelay);
   if (
     command.length < 2 ||
     command[0] !== 'sub-seek' ||
@@ -124,5 +127,5 @@ export function resolveSanitizedSubtitleSeekCommand(
   if (!destination) {
     return null;
   }
-  return ['seek', subtitleCueSeekTime(destination.cue), 'absolute+exact'];
+  return ['seek', toVideoClock(subtitleCueSeekTime(destination.cue), subDelay), 'absolute+exact'];
 }

src/main.ts

@@ -332,6 +332,7 @@ import {
   showMpvOsdRuntime,
   JellyfinPlaybackReporter,
   tokenizeSubtitle as tokenizeSubtitleCore,
+  toSubtitleClock,
   triggerFieldGrouping as triggerFieldGroupingCore,
   upsertYomitanDictionarySettings,
   updateLastCardFromClipboard as updateLastCardFromClipboardCore,
@@ -1938,7 +1939,10 @@ let tokenizeSubtitleDeferred: ((text: string) => Promise<SubtitleData>) | null =
 function withCurrentSubtitleTiming(payload: SubtitleData): SubtitleData {
   const canonical = resolveCanonicalPrimarySubtitle({
     liveText: payload.text,
-    currentTimeSec: Number(appState.mpvClient?.currentTimePos),
+    currentTimeSec: toSubtitleClock(
+      Number(appState.mpvClient?.currentTimePos),
+      appState.mpvClient?.currentSubDelay ?? 0,
+    ),
     cues: appState.activeParsedSubtitleCues,
   });
   return {
@@ -1956,7 +1960,7 @@ function captureCurrentPrimarySubtitleMiningContext(): SubtitleMiningContext | n
   const subDelay = appState.mpvClient?.currentSubDelay ?? 0;
   const resolved = resolvePrimarySubtitle({
     liveText: appState.mpvClient?.currentSubText ?? '',
-    currentTimeSec: Number(appState.mpvClient?.currentTimePos) - subDelay,
+    currentTimeSec: toSubtitleClock(Number(appState.mpvClient?.currentTimePos), subDelay),
     cues: appState.activeParsedSubtitleCues,
   });
   // Same validity bar as the live capture path: an unusable resolved span must fall
@@ -2122,13 +2126,18 @@ function getSubtitleSidebarPlaybackState(): SubtitleSidebarPlaybackState {
     subtitleSidebarCuesRef = appState.activeParsedSubtitleCues;
     subtitleSidebarCuesRevision += 1;
   }
+  const subDelay = appState.mpvClient?.currentSubDelay ?? 0;
   return {
     sourceKey: JSON.stringify([
       appState.activeParsedSubtitleMediaPath,
       appState.activeParsedSubtitleSource,
     ]),
     cuesRevision: subtitleSidebarCuesRevision,
-    currentTimeSec: appState.mpvClient?.currentTimePos ?? null,
+    currentTimeSec:
+      appState.mpvClient?.currentTimePos === undefined
+        ? null
+        : toSubtitleClock(appState.mpvClient.currentTimePos, subDelay),
+    subDelay,
     currentSubtitle: {
       text: appState.currentSubText,
       startTime: appState.mpvClient?.currentSubStart ?? null,
@@ -2167,6 +2176,7 @@ function sendRendererMpvCommand(rawCommand: (string | number)[]): void {
       rawCommand,
       appState.activeParsedSubtitleCues,
       appState.mpvClient?.currentTimePos ?? Number.NaN,
+      appState.mpvClient?.currentSubDelay ?? 0,
     ) ?? rawCommand;
   if (isExplicitMpvSeekCommand(command)) {
     explicitSeekIntentExpiresAtMs = Date.now() + EXPLICIT_SEEK_INTENT_TTL_MS;

src/main/runtime/autoplay-subtitle-priming-runtime.ts

@@ -1,3 +1,4 @@
+import { toSubtitleClock } from '../../core/services/subtitle-clock';
 import type { SubtitleCue, SubtitleData } from '../../types';
 import { selectAutoplayStartupCue } from './autoplay-subtitle-primer';
 import { primeVisibleOverlaySubtitleFromMpv } from './current-subtitle-snapshot';
@@ -12,6 +13,7 @@ type AutoplaySubtitlePrimingMpvClient = {
   requestProperty: (name: string) => Promise<unknown>;
   currentVideoPath?: string;
   currentTimePos?: number;
+  currentSubDelay?: number;
   currentSubText?: string;
   currentSecondarySubText?: string;
   setCurrentSecondarySubText?: (text: string) => void;
@@ -156,7 +158,7 @@ export function createAutoplaySubtitlePrimingRuntime(deps: AutoplaySubtitlePrimi
     const currentTimeSec = Number(client?.currentTimePos ?? deps.getLastObservedTimePos());
     return resolvePrimarySubtitleText({
       liveText: text,
-      currentTimeSec,
+      currentTimeSec: toSubtitleClock(currentTimeSec, client?.currentSubDelay ?? 0),
       cues: deps.getActiveParsedSubtitleCues(),
     });
   }
@@ -270,7 +272,10 @@ export function createAutoplaySubtitlePrimingRuntime(deps: AutoplaySubtitlePrimi
     const currentTimeSeconds = Number(
       timePosRaw ?? client?.currentTimePos ?? deps.getLastObservedTimePos() ?? 0,
     );
-    const resolvedTimeSeconds = Number.isFinite(currentTimeSeconds) ? currentTimeSeconds : 0;
+    const resolvedTimeSeconds = toSubtitleClock(
+      Number.isFinite(currentTimeSeconds) ? currentTimeSeconds : 0,
+      client?.currentSubDelay ?? 0,
+    );
     const cue = selectAutoplayStartupCue(
       cues,
       resolvedTimeSeconds,

src/main/runtime/mpv-main-event-main-deps.ts

@@ -1,3 +1,4 @@
+import { toSubtitleClock } from '../../core/services/subtitle-clock';
 import { createSubtitleLineDedupGate } from '../../core/services/subtitle-line-dedup-gate';
 import type { MergedToken, SubtitleCue, SubtitleData } from '../../types';
 import {
@@ -162,7 +163,10 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
     resolveSubtitleText: (liveText: string) =>
       resolvePrimarySubtitleText({
         liveText,
-        currentTimeSec: Number(deps.appState.mpvClient?.currentTimePos),
+        currentTimeSec: toSubtitleClock(
+          Number(deps.appState.mpvClient?.currentTimePos),
+          deps.appState.mpvClient?.currentSubDelay ?? 0,
+        ),
         cues: deps.appState.activeParsedSubtitleCues,
       }),
     getCurrentLiveSubtitleText: () => deps.appState.mpvClient?.currentSubText ?? '',

src/renderer/modals/subtitle-sidebar-selection.electron-fixture.ts

@@ -28,6 +28,7 @@ export async function setup() {
     ],
     currentSubtitle: { text: '最初の台詞', startTime: 0, endTime: 1 },
     currentTimeSec: 0,
+    subDelay: 0,
     config: {
       ...SUBTITLE_DEFAULT_CONFIG.subtitleSidebar,
       enabled: true,

src/renderer/modals/subtitle-sidebar.test.ts

@@ -199,6 +199,7 @@ function createSidebarHarness(options: SidebarHarnessOptions = {}) {
     cues: options.cues ?? [{ startTime: 1, endTime: 2, text: 'first' }],
     currentSubtitle: options.currentSubtitle ?? { text: 'first', startTime: 1, endTime: 2 },
     currentTimeSec: 'currentTimeSec' in options ? (options.currentTimeSec ?? null) : 1.1,
+    subDelay: 0,
     config: { ...DEFAULT_SIDEBAR_CONFIG, ...options.config },
   };
   const requests = { snapshot: 0, playback: 0 };
@@ -226,8 +227,8 @@ function createSidebarHarness(options: SidebarHarnessOptions = {}) {
         },
         getSubtitleSidebarPlaybackState: async (): Promise<SubtitleSidebarPlaybackState> => {
           requests.playback += 1;
-          const { sourceKey, cuesRevision, currentTimeSec, currentSubtitle } = snapshot;
+          const { sourceKey, cuesRevision, currentTimeSec, subDelay, currentSubtitle } = snapshot;
-          return { sourceKey, cuesRevision, currentTimeSec, currentSubtitle };
+          return { sourceKey, cuesRevision, currentTimeSec, subDelay, currentSubtitle };
         },
         getPlaybackPaused: async () => false,
         sendMpvCommand: (command: MpvCommand) => {
@@ -528,6 +529,16 @@ test('subtitle sidebar seeks to the selected cue start using the overlap-aware s
   assert.deepEqual(h.mpvCommands.at(-1), ['seek', 3.48, 'absolute+exact']);
 });
 
+test('subtitle sidebar seeks to where mpv plays a sub-delay retimed cue', async () => {
+  const h = createSidebarHarness();
+  h.setSnapshot({ subDelay: 2 });
+  await h.modal.openSubtitleSidebarModal();
+
+  h.modal.seekToCue({ startTime: 1, endTime: 2, text: 'first' });
+
+  assert.deepEqual(h.mpvCommands.at(-1), ['seek', 3.08, 'absolute+exact']);
+});
+
 test('subtitle sidebar close reports hidden visibility and notifies the modal close', async () => {
   const h = createSidebarHarness();
   await h.modal.openSubtitleSidebarModal();

src/renderer/modals/subtitle-sidebar.ts

@@ -4,6 +4,7 @@ import type {
   SubtitleMiningContext,
   SubtitleSidebarSnapshot,
 } from '../../types';
+import { toVideoClock } from '../../core/services/subtitle-clock.js';
 import { subtitleCueListSeekTime } from '../../core/services/subtitle-cue-navigation.js';
 import type { ModalStateReader, RendererContext } from '../context';
 import { syncOverlayMouseIgnoreState } from '../overlay-mouse-ignore.js';
@@ -231,6 +232,8 @@ export function createSubtitleSidebarModal(
   let lastSubtitleSidebarLookupCueIndex = -1;
   let subtitleSourceKey: string | null = null;
   let subtitleCuesRevision: number | null = null;
+  // Latest mpv `sub-delay` from main; cue times plus this are where mpv plays the cue.
+  let subtitleSubDelay = 0;
 
   function restoreEmbeddedSidebarPassthrough(): void {
     syncOverlayMouseIgnoreState(ctx);
@@ -416,7 +419,7 @@ export function createSubtitleSidebarModal(
   function seekToCue(cue: SubtitleCue): void {
     window.electronAPI.sendMpvCommand([
       'seek',
-      subtitleCueListSeekTime(ctx.state.subtitleSidebarCues, cue),
+      toVideoClock(subtitleCueListSeekTime(ctx.state.subtitleSidebarCues, cue), subtitleSubDelay),
       'absolute+exact',
     ]);
   }
@@ -591,6 +594,7 @@ export function createSubtitleSidebarModal(
     const snapshot = await window.electronAPI.getSubtitleSidebarSnapshot();
     pollsSinceFullSnapshot = 0;
     subtitleCuesRevision = snapshot.cuesRevision;
+    subtitleSubDelay = snapshot.subDelay;
     if (snapshot.sourceKey !== subtitleSourceKey) {
       clearSubtitleSidebarSelection(ctx.dom.subtitleSidebarList);
       lastSubtitleSidebarLookupCueIndex = -1;
@@ -640,6 +644,7 @@ export function createSubtitleSidebarModal(
       await refreshSnapshot();
       return;
     }
+    subtitleSubDelay = playback.subDelay;
     updateActiveCue(playback.currentSubtitle, playback.currentTimeSec);
   }
 

src/types/subtitle.ts

@@ -235,7 +235,10 @@ export interface SubtitleSidebarPlaybackState {
   sourceKey: string | null;
   /** Bumps whenever main swaps in a different parsed cue array. */
   cuesRevision: number;
+  /** Playback position on the subtitle clock (`time-pos` minus `sub-delay`), like cue times. */
   currentTimeSec: number | null;
+  /** mpv `sub-delay`: cue times plus this give the video-clock seek target. */
+  subDelay: number;
   currentSubtitle: {
     text: string;
     startTime: number | null;