fix(subtitles): collapse layered ASS lyrics across startup and seeks

- Reconstruct fragment-only karaoke while preserving canonical animated signs
- Reprocess live subtitles after initial playback and seek updates
- Add a development launcher for playable media files

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

@@ -149,8 +149,8 @@ function collectRepeatedPhaseRuns(cues: AnnotatedSubtitleCue[]): RepeatedPhaseRu
       const isFlush =
         Math.abs(next.startTime - current.endTime) <= DUPLICATE_CUE_GAP_TOLERANCE_SECONDS;
       if (
-        first.source === 'canonical-ass' ||
-        next.source === 'canonical-ass' ||
+        first.source !== undefined ||
+        next.source !== undefined ||
         next.text !== first.text ||
         assStyleKey(next) !== styleKey ||
         !isFlush
@@ -223,7 +223,7 @@ function countFramesShorterThan(run: AnnotatedSubtitleCue[], maxSeconds: number)
  * anything wrapped in `\t(...)`), an animated `Effect` column, or a value that actually
  * changes from event to event, which is how per-frame typesetting is authored.
  */
-export function hasAssAnimationEvidence(run: AnnotatedSubtitleCue[]): boolean {
+export function hasAssAnimationEvidence(run: readonly AnnotatedSubtitleCue[]): boolean {
   if (run.every((cue) => hasAssTemporalOverride(cue.overrides))) {
     return true;
   }

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

@@ -570,6 +570,63 @@ test('parseSubtitleCues does not promote a short animated fragment as a complete
   );
 });
 
+test('parseSubtitleCues keeps short animated English dialogue as separate cues', () => {
+  const content = [
+    '[Events]',
+    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
+    'Dialogue: 0,0:00:01.00,0:00:02.00,English Dialogue,,0,0,0,,{\\t(0,100,\\fscx110)}Hi',
+    'Dialogue: 0,0:00:02.00,0:00:03.00,English Dialogue,,0,0,0,,{\\t(0,100,\\fscx110)}No',
+  ].join('\n');
+
+  assert.deepEqual(parseSubtitleCues(content, 'test.ass'), [
+    { startTime: 1, endTime: 2, text: 'Hi' },
+    { startTime: 2, endTime: 3, text: 'No' },
+  ]);
+});
+
+test('parseSubtitleCues does not reconstruct an already canonical English cue', () => {
+  const content = [
+    '[Events]',
+    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
+    'Comment: 0,0:00:01.00,0:00:03.00,OP English,,0,0,0,,{\\move(100,100,120,100)}POOF',
+    'Dialogue: 0,0:00:01.00,0:00:01.04,OP English,,0,0,0,,{\\pos(100,100)\\clip(m 1 1)}POOF',
+    'Dialogue: 0,0:00:01.04,0:00:01.08,OP English,,0,0,0,,{\\pos(100,100)\\clip(m 2 2)}POOF',
+    'Dialogue: 0,0:00:01.08,0:00:03.00,OP English,,0,0,0,,{\\pos(100,100)\\clip(m 3 3)}POOF',
+  ].join('\n');
+
+  assert.deepEqual(parseSubtitleCues(content, 'test.ass'), [
+    {
+      startTime: 1,
+      endTime: 3,
+      text: 'POOF',
+      source: 'canonical-ass',
+      animationStartTime: 1,
+      animationEndTime: 3,
+    },
+  ]);
+});
+
+test('parseSubtitleCues reconstructs a short positioned fragment without a lyric style name', () => {
+  const content = [
+    '[Events]',
+    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
+    'Dialogue: 0,0:00:01.00,0:00:03.00,Karaoke,,0,0,0,,{\\pos(100,100)\\t(0,100,\\fscx110)}Oh',
+    'Dialogue: 1,0:00:01.00,0:00:03.00,Karaoke,,0,0,0,,{\\pos(100,100)\\t(0,100,\\fscx110)}Oh',
+  ].join('\n');
+
+  assert.deepEqual(parseSubtitleCues(content, 'test.ass'), [
+    {
+      startTime: 1,
+      endTime: 3,
+      text: 'Oh',
+      source: 'reconstructed-ass',
+      animationStartTime: 1,
+      animationEndTime: 3,
+      assStyle: 'Karaoke',
+    },
+  ]);
+});
+
 test('parseSubtitleCues ignores timed comments without a matching animated dialogue cluster', () => {
   const content = [
     '[Events]',

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

@@ -8,19 +8,26 @@ import {
 } from './ass-text';
 import { hasAssAnimationEvidence, mergeDuplicateCues } from './subtitle-cue-dedup';
 
+export type AssCueLayout =
+  | { kind: 'positioned'; sourceOrder: number; y: number }
+  | { kind: 'source-order'; sourceOrder: number };
+
 export interface SubtitleCue {
   startTime: number;
   endTime: number;
   text: string;
-  /** A complete authored line recovered from matching generated ASS animation events. */
-  source?: 'canonical-ass';
+  /** How a complete line was recovered from generated ASS animation events. */
+  source?: 'canonical-ass' | 'reconstructed-ass';
   /**
-   * Full span of the generated animation events a canonical cue replaced. Entrance and
-   * exit frames routinely run past the authored `startTime`/`endTime`, so live-text
-   * matching must use this envelope while display and history keep the authored timing.
+   * Full span of the generated animation events a recovered cue replaced. Entrance and
+   * exit frames can run past canonical authored timing.
    */
   animationStartTime?: number;
   animationEndTime?: number;
+  /** ASS style retained only for fragment-reconstructed lines. */
+  assStyle?: string;
+  /** Authored ASS ordering metadata used when flattening simultaneous positioned cues. */
+  assLayout?: AssCueLayout;
 }
 
 /**
@@ -29,7 +36,7 @@ export interface SubtitleCue {
  * override commands it carries, whether the `Effect` column was set -- to tell a karaoke
  * burst apart from two characters saying the same word in turn. None of it is meaningful
  * outside the parser, so the public API exposes only timing, text, and the optional
- * canonical-source marker used by live subtitle consumers.
+ * recovery marker used by live subtitle consumers.
  */
 export interface AnnotatedSubtitleCue extends SubtitleCue {
   /** Text exactly as authored, override blocks and all. */
@@ -75,15 +82,55 @@ function parseTimestamp(
  * line breaks, matching what mpv hands over for the same line played live. No layer
  * downstream decodes ASS again.
  */
+function decodeSubtitleCueText(text: string): string {
+  return assToPlainText(text, '\n').replace(HTML_SUBTITLE_TAG_PATTERN, '');
+}
+
 function sanitizeSubtitleCueText(text: string): string {
-  return assToPlainText(text, '\n').replace(HTML_SUBTITLE_TAG_PATTERN, '').trim();
+  return decodeSubtitleCueText(text).trim();
+}
+
+function attachAssLayout<T extends SubtitleCue>(cue: T, assLayout: AssCueLayout | undefined): T {
+  if (assLayout) {
+    Object.defineProperty(cue, 'assLayout', { value: assLayout, enumerable: false });
+  }
+  return cue;
 }
 
 function toPublicCues(cues: AnnotatedSubtitleCue[]): SubtitleCue[] {
-  return cues.map(({ startTime, endTime, text, source, animationStartTime, animationEndTime }) =>
-    source
-      ? { startTime, endTime, text, source, animationStartTime, animationEndTime }
-      : { startTime, endTime, text },
+  return cues.map(
+    ({
+      startTime,
+      endTime,
+      text,
+      source,
+      animationStartTime,
+      animationEndTime,
+      style,
+      assLayout,
+    }) => {
+      const common = {
+        startTime,
+        endTime,
+        text,
+      };
+      if (source === 'reconstructed-ass') {
+        return attachAssLayout(
+          {
+            ...common,
+            source,
+            animationStartTime,
+            animationEndTime,
+            assStyle: style,
+          },
+          assLayout,
+        );
+      }
+      return attachAssLayout(
+        source ? { ...common, source, animationStartTime, animationEndTime } : common,
+        assLayout,
+      );
+    },
   );
 }
 
@@ -159,6 +206,10 @@ const MIN_CANONICAL_ANIMATION_EVENTS = 3;
 // A tiny animated fragment can itself be composed from still smaller glyph events. It is
 // not enough evidence that the fragment represents an authored line boundary.
 const MIN_CANONICAL_DIALOGUE_TEXT_LENGTH = 4;
+const MIN_FRAGMENT_LINE_EVENTS = 8;
+const MIN_FRAGMENT_LINE_PARTS = 4;
+const MAX_FRAGMENT_MEDIAN_LENGTH = 4;
+const MAX_FRAGMENT_LINE_TIMING_VARIANCE_SECONDS = 2;
 
 function parseAssTimestamp(raw: string): number | null {
   const match = ASS_TIMING_PATTERN.exec(raw.trim());
@@ -296,6 +347,215 @@ function isRepeatedFragmentCopy(
   );
 }
 
+function hasRelaxedAssFragmentEvidence(events: readonly AnnotatedSubtitleCue[]): boolean {
+  if (events.length < 2 || !events.every((event) => fragmentPlacementAnchors(event).size > 0)) {
+    return false;
+  }
+
+  const latestStart = events.reduce(
+    (latest, event) => Math.max(latest, event.startTime),
+    -Infinity,
+  );
+  const earliestEnd = events.reduce(
+    (earliest, event) => Math.min(earliest, event.endTime),
+    Infinity,
+  );
+  if (latestStart >= earliestEnd) {
+    return false;
+  }
+
+  const first = events[0]!;
+  const hasChangingOverrides = events.some(
+    (event) => event.overrideSignature !== first.overrideSignature,
+  );
+  const hasPositionedLayerCopy = events.some((event, index) =>
+    events
+      .slice(0, index)
+      .some(
+        (previous) =>
+          compactCueMatchText(previous) === compactCueMatchText(event) &&
+          isRepeatedFragmentCopy(previous, event),
+      ),
+  );
+  return hasChangingOverrides || hasPositionedLayerCopy;
+}
+
+interface AssFragmentPart {
+  cue: AnnotatedSubtitleCue;
+  text: string;
+}
+
+interface AssFragmentTimingCluster {
+  events: AnnotatedSubtitleCue[];
+  minStartTime: number;
+  maxStartTime: number;
+  minEndTime: number;
+  maxEndTime: number;
+}
+
+function addToFragmentTimingCluster(
+  cluster: AssFragmentTimingCluster,
+  cue: AnnotatedSubtitleCue,
+): void {
+  cluster.events.push(cue);
+  cluster.minStartTime = Math.min(cluster.minStartTime, cue.startTime);
+  cluster.maxStartTime = Math.max(cluster.maxStartTime, cue.startTime);
+  cluster.minEndTime = Math.min(cluster.minEndTime, cue.endTime);
+  cluster.maxEndTime = Math.max(cluster.maxEndTime, cue.endTime);
+}
+
+function fragmentTimingDistance(
+  cluster: AssFragmentTimingCluster,
+  cue: AnnotatedSubtitleCue,
+): number {
+  const nextMinStart = Math.min(cluster.minStartTime, cue.startTime);
+  const nextMaxStart = Math.max(cluster.maxStartTime, cue.startTime);
+  const nextMinEnd = Math.min(cluster.minEndTime, cue.endTime);
+  const nextMaxEnd = Math.max(cluster.maxEndTime, cue.endTime);
+  if (
+    nextMaxStart - nextMinStart > MAX_FRAGMENT_LINE_TIMING_VARIANCE_SECONDS ||
+    nextMaxEnd - nextMinEnd > MAX_FRAGMENT_LINE_TIMING_VARIANCE_SECONDS
+  ) {
+    return Infinity;
+  }
+  return (
+    Math.abs(cue.startTime - (cluster.minStartTime + cluster.maxStartTime) / 2) +
+    Math.abs(cue.endTime - (cluster.minEndTime + cluster.maxEndTime) / 2)
+  );
+}
+
+function clusterAssFragmentEvents(
+  events: readonly AnnotatedSubtitleCue[],
+): AssFragmentTimingCluster[] {
+  const clusters: AssFragmentTimingCluster[] = [];
+  for (const cue of events) {
+    let nearest: AssFragmentTimingCluster | null = null;
+    let nearestDistance = Infinity;
+    for (const cluster of clusters) {
+      const distance = fragmentTimingDistance(cluster, cue);
+      if (distance < nearestDistance) {
+        nearest = cluster;
+        nearestDistance = distance;
+      }
+    }
+    if (nearest) {
+      addToFragmentTimingCluster(nearest, cue);
+    } else {
+      clusters.push({
+        events: [cue],
+        minStartTime: cue.startTime,
+        maxStartTime: cue.startTime,
+        minEndTime: cue.endTime,
+        maxEndTime: cue.endTime,
+      });
+    }
+  }
+  return clusters;
+}
+
+function decodeSingleAssFragment(cue: AnnotatedSubtitleCue): string | null {
+  const visibleLines = decodeSubtitleCueText(cue.rawText)
+    .split('\n')
+    .filter((line) => line.trim().length > 0);
+  return visibleLines.length === 1 ? visibleLines[0]! : null;
+}
+
+function reconstructAssFragmentLine(
+  events: readonly AnnotatedSubtitleCue[],
+): AnnotatedSubtitleCue | null {
+  const hasRelaxedEvidence = hasRelaxedAssFragmentEvidence(events);
+  const minimumEvents = hasRelaxedEvidence ? 2 : MIN_FRAGMENT_LINE_EVENTS;
+  if (events.length < minimumEvents || !hasAssAnimationEvidence(events)) {
+    return null;
+  }
+
+  const parts: AssFragmentPart[] = [];
+  for (const cue of events) {
+    const text = decodeSingleAssFragment(cue);
+    if (text === null) {
+      return null;
+    }
+    const compactText = compactAssMatchText(text);
+    const isLayerCopy = parts.some(
+      (part) =>
+        compactAssMatchText(part.text) === compactText && isRepeatedFragmentCopy(part.cue, cue),
+    );
+    if (!isLayerCopy) {
+      parts.push({ cue, text });
+    }
+  }
+
+  const minimumParts = hasRelaxedEvidence ? 1 : MIN_FRAGMENT_LINE_PARTS;
+  if (parts.length < minimumParts || (!hasRelaxedEvidence && parts.length === events.length)) {
+    return null;
+  }
+  const lengths = parts
+    .map((part) => compactAssMatchText(part.text).length)
+    .sort((left, right) => left - right);
+  if ((lengths[Math.floor(lengths.length / 2)] ?? Infinity) > MAX_FRAGMENT_MEDIAN_LENGTH) {
+    return null;
+  }
+
+  const text = parts
+    .map((part) => part.text)
+    .join('')
+    .trim();
+  if (!text) {
+    return null;
+  }
+  const owner = parts[0]!.cue;
+  const animationStartTime = earliestStartTime(events);
+  const animationEndTime = latestEndTime(events);
+  return {
+    ...owner,
+    startTime: animationStartTime,
+    endTime: animationEndTime,
+    text,
+    rawText: text,
+    source: 'reconstructed-ass',
+    animationStartTime,
+    animationEndTime,
+    overrides: [],
+    overrideSignature: '',
+  };
+}
+
+function recoverFragmentOnlyAssLines(dialogue: AnnotatedSubtitleCue[]): AnnotatedSubtitleCue[] {
+  const groups = new Map<string, AnnotatedSubtitleCue[]>();
+  for (const cue of dialogue) {
+    if (cue.source !== undefined) {
+      continue;
+    }
+    const key = assEventGroupKey(cue);
+    const group = groups.get(key);
+    if (group) {
+      group.push(cue);
+    } else {
+      groups.set(key, [cue]);
+    }
+  }
+
+  const recovered: AnnotatedSubtitleCue[] = [];
+  const suppressed = new Set<AnnotatedSubtitleCue>();
+  for (const events of groups.values()) {
+    for (const cluster of clusterAssFragmentEvents(events)) {
+      const line = reconstructAssFragmentLine(cluster.events);
+      if (!line) {
+        continue;
+      }
+      recovered.push(line);
+      cluster.events.forEach((event) => suppressed.add(event));
+    }
+  }
+  if (recovered.length === 0) {
+    return dialogue;
+  }
+  return [...dialogue.filter((cue) => !suppressed.has(cue)), ...recovered].sort(
+    (left, right) =>
+      left.startTime - right.startTime || left.endTime - right.endTime || left.order - right.order,
+  );
+}
+
 function groupConsecutiveAssFragments(events: readonly AnnotatedSubtitleCue[]): FragmentGroup[] {
   const groups: FragmentGroup[] = [];
   for (const event of events) {
@@ -507,6 +767,37 @@ function recoverCanonicalAssEvents({
   );
 }
 
+function parseAssCoordinate(value: string | undefined): number | null {
+  if (!value?.trim()) return null;
+  const coordinate = Number(value.trim());
+  return Number.isFinite(coordinate) ? coordinate : null;
+}
+
+function buildAssCueLayout(
+  overrides: readonly AssOverrideCommand[],
+  sourceOrder: number,
+): AssCueLayout {
+  let y: number | null = null;
+  for (const command of overrides) {
+    if (command.animated) continue;
+    const name = command.name.toLowerCase();
+    const args = command.args.split(',');
+    if (name === 'pos') {
+      y = parseAssCoordinate(args[1]) ?? y;
+      continue;
+    }
+    if (name !== 'move') continue;
+    const startY = parseAssCoordinate(args[1]);
+    const endY = parseAssCoordinate(args[3]);
+    if (startY !== null && endY !== null) {
+      y = (startY + endY) / 2;
+    }
+  }
+  return y === null
+    ? { kind: 'source-order', sourceOrder }
+    : { kind: 'positioned', sourceOrder, y };
+}
+
 function parseAnnotatedAssEvents(content: string): ParsedAssEvents {
   const cues: AnnotatedSubtitleCue[] = [];
   const comments: AnnotatedSubtitleCue[] = [];
@@ -615,6 +906,7 @@ function parseAnnotatedAssEvents(content: string): ParsedAssEvents {
       overrides,
       overrideSignature: assOverrideSignature(overrides),
       order: eventOrder,
+      assLayout: buildAssCueLayout(overrides, eventOrder),
     };
     eventOrder += 1;
     if (eventPrefix === ASS_COMMENT_PREFIX) {
@@ -628,7 +920,7 @@ function parseAnnotatedAssEvents(content: string): ParsedAssEvents {
 }
 
 function parseAnnotatedAssCues(content: string): AnnotatedSubtitleCue[] {
-  return recoverCanonicalAssEvents(parseAnnotatedAssEvents(content));
+  return recoverFragmentOnlyAssLines(recoverCanonicalAssEvents(parseAnnotatedAssEvents(content)));
 }
 
 export function parseAssCues(content: string): SubtitleCue[] {

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

@@ -1,5 +1,6 @@
 import assert from 'node:assert/strict';
 import test from 'node:test';
+import { parseSubtitleCues } from '../../core/services/subtitle-cue-parser';
 import { createSubtitleProcessingController } from '../../core/services/subtitle-processing-controller';
 import type { SubtitleData } from '../../types';
 import {
@@ -211,6 +212,69 @@ test('primeCurrentSubtitleForAutoplay emits raw first paint on cache miss before
   ]);
 });
 
+test('parsed cues replace a duplicate raw autoplay subtitle that was already primed', async () => {
+  const rawText = 'ジグザグな道を抜け\nジグザグな道を抜け';
+  const correctedText = 'ジグザグな道を抜け';
+  const mediaPath = '/media/video.mkv';
+  let currentSubText = '';
+  const emitted: string[] = [];
+  const client = {
+    connected: true,
+    currentVideoPath: mediaPath,
+    currentTimePos: 90,
+    currentSubText: rawText,
+    requestProperty: async (name: string) => {
+      if (name === 'sub-text') return rawText;
+      if (name === 'time-pos') return 90;
+      return null;
+    },
+  };
+  const cues = parseSubtitleCues(
+    [
+      '[Events]',
+      'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
+      `Dialogue: 1,0:01:29.00,0:01:32.00,EDJP,,0,0,0,,${correctedText}`,
+      `Dialogue: 0,0:01:29.00,0:01:32.00,EDJP,,0,0,0,,${correctedText}`,
+    ].join('\n'),
+    'startup-ending.ass',
+  );
+  let activeCues = cues.slice(0, 0);
+  const runtime = createAutoplaySubtitlePrimingRuntime({
+    getCurrentMediaPath: () => mediaPath,
+    getMpvClient: () => client,
+    setCurrentSubText: (text) => {
+      currentSubText = text;
+    },
+    getCurrentSubText: () => currentSubText,
+    getCurrentSubtitleData: () => null,
+    getActiveParsedSubtitleCues: () => activeCues,
+    setActiveParsedSubtitleMediaPath: () => {},
+    subtitleProcessingController: {
+      consumeCachedSubtitle: () => null,
+      onSubtitleChange: () => true,
+      refreshCurrentSubtitle: () => true,
+      notePlainSubtitleEmitted: () => {},
+    },
+    emitSubtitlePayload: (payload) => emitted.push(payload.text),
+    getSubtitlePrefetchService: () => null,
+    getLastObservedTimePos: () => 90,
+    getVisibleOverlayVisible: () => true,
+    emitSecondarySubtitle: () => {},
+    initSubtitlePrefetch: async () => {},
+    refreshSubtitlePrefetchFromActiveTrack: async () => {},
+    logDebug: () => {},
+  });
+
+  await runtime.primeCurrentSubtitleForAutoplay(mediaPath);
+  assert.equal(currentSubText, rawText);
+
+  activeCues = cues;
+  await runtime.primeAutoplaySubtitleFromParsedCues(mediaPath, cues);
+
+  assert.equal(currentSubText, correctedText);
+  assert.deepEqual(emitted, [rawText, correctedText]);
+});
+
 // Driven by the real processing controller rather than a stub: the failure this
 // covers is a disagreement between the priming path and the controller's own
 // staleness rules, which a hand-written stub cannot reproduce.

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

@@ -12,6 +12,7 @@ type AutoplaySubtitlePrimingMpvClient = {
   requestProperty: (name: string) => Promise<unknown>;
   currentVideoPath?: string;
   currentTimePos?: number;
+  currentSubText?: string;
   currentSecondarySubText?: string;
   setCurrentSecondarySubText?: (text: string) => void;
 };
@@ -107,11 +108,19 @@ export function createAutoplaySubtitlePrimingRuntime(deps: AutoplaySubtitlePrimi
     autoplaySubtitlePrimedMediaPath = null;
   }
 
-  function emitAutoplayPrimedSubtitle(mediaPath: string, text: string): boolean {
+  function emitAutoplayPrimedSubtitle(
+    mediaPath: string,
+    text: string,
+    options: { replaceExisting?: boolean } = {},
+  ): boolean {
     if (!text.trim() || !isCurrentAutoplayMediaPath(mediaPath)) {
       return false;
     }
-    if (!markAutoplaySubtitlePrimeConsumed(mediaPath)) {
+    if (autoplaySubtitlePrimedMediaPath === mediaPath) {
+      if (!options.replaceExisting || deps.getCurrentSubText() === text) {
+        return false;
+      }
+    } else if (!markAutoplaySubtitlePrimeConsumed(mediaPath)) {
       return false;
     }
 
@@ -252,11 +261,7 @@ export function createAutoplaySubtitlePrimingRuntime(deps: AutoplaySubtitlePrimi
     mediaPath: string,
     cues: SubtitleCue[],
   ): Promise<void> {
-    if (
-      cues.length === 0 ||
-      autoplaySubtitlePrimedMediaPath === mediaPath ||
-      !isCurrentAutoplayMediaPath(mediaPath)
-    ) {
+    if (cues.length === 0 || !isCurrentAutoplayMediaPath(mediaPath)) {
       return;
     }
 
@@ -265,16 +270,21 @@ export function createAutoplaySubtitlePrimingRuntime(deps: AutoplaySubtitlePrimi
     const currentTimeSeconds = Number(
       timePosRaw ?? client?.currentTimePos ?? deps.getLastObservedTimePos() ?? 0,
     );
+    const resolvedTimeSeconds = Number.isFinite(currentTimeSeconds) ? currentTimeSeconds : 0;
     const cue = selectAutoplayStartupCue(
       cues,
-      Number.isFinite(currentTimeSeconds) ? currentTimeSeconds : 0,
+      resolvedTimeSeconds,
       AUTOPLAY_SUBTITLE_PRIME_LOOKAHEAD_SECONDS,
     );
-    if (!cue) {
+    const liveText = client?.currentSubText ?? '';
+    const text = liveText.trim()
+      ? resolvePrimarySubtitleText({ liveText, currentTimeSec: resolvedTimeSeconds, cues })
+      : (cue?.text ?? '');
+    if (!text) {
       return;
     }
 
-    emitAutoplayPrimedSubtitle(mediaPath, cue.text);
+    emitAutoplayPrimedSubtitle(mediaPath, text, { replaceExisting: true });
   }
 
   function clearScheduledSubtitlePrefetchRefresh(): void {

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

@@ -4,6 +4,8 @@ type AnilistPostWatchRunOptions = {
   watchedSeconds?: number;
 };
 
+type TimePosUpdateKind = 'initial' | 'playback' | 'seek';
+
 /** Jump size that marks a time-pos change as a seek rather than normal playback. */
 export const SEEK_LIKE_TIME_DELTA_SECONDS = 2.5;
 
@@ -138,12 +140,18 @@ export function createHandleMpvTimePosChangeHandler(deps: {
   refreshDiscordPresence: () => void;
   maybeRunAnilistPostWatchUpdate?: (options?: AnilistPostWatchRunOptions) => Promise<void>;
   logError?: (message: string, error: unknown) => void;
-  onTimePosUpdate?: (time: number) => void;
+  onTimePosUpdate?: (time: number, kind: TimePosUpdateKind) => void;
 }) {
   let lastObservedTime: number | null = null;
 
   return ({ time }: { time: number }): void => {
-    const forceImmediate = isSeekLikeTimeChange(lastObservedTime, time);
+    const updateKind: TimePosUpdateKind =
+      lastObservedTime === null
+        ? 'initial'
+        : isSeekLikeTimeChange(lastObservedTime, time)
+          ? 'seek'
+          : 'playback';
+    const forceImmediate = updateKind === 'seek';
     if (Number.isFinite(time)) {
       lastObservedTime = time;
     }
@@ -153,7 +161,7 @@ export function createHandleMpvTimePosChangeHandler(deps: {
     void deps.maybeRunAnilistPostWatchUpdate?.({ watchedSeconds: time }).catch((error) => {
       deps.logError?.('AniList post-watch update failed unexpectedly', error);
     });
-    deps.onTimePosUpdate?.(time);
+    deps.onTimePosUpdate?.(time, updateKind);
   };
 }
 

src/main/runtime/mpv-main-event-bindings.test.ts

@@ -1,10 +1,23 @@
 import assert from 'node:assert/strict';
 import test from 'node:test';
+import { parseSubtitleCues } from '../../core/services/subtitle-cue-parser';
 import { createBindMpvMainEventHandlersHandler } from './mpv-main-event-bindings';
+import { resolvePrimarySubtitleText } from './primary-subtitle-text';
 
 test('main mpv event binder wires callbacks through to runtime deps', () => {
   const handlers = new Map<string, (payload: unknown) => void>();
   const calls: string[] = [];
+  let currentTime = 0;
+  const seekLiveText = '少しだけ好きになる\n少しだけ好きになる';
+  const seekCues = parseSubtitleCues(
+    [
+      '[Events]',
+      'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
+      'Dialogue: 1,0:01:29.00,0:01:32.00,EDJP,,0,0,0,,少しだけ好きになる',
+      'Dialogue: 0,0:01:29.00,0:01:32.00,EDJP,,0,0,0,,少しだけ好きになる',
+    ].join('\n'),
+    'seek-ending.ass',
+  );
 
   const bind = createBindMpvMainEventHandlersHandler({
     reportJellyfinRemoteStopped: () => calls.push('remote-stopped'),
@@ -27,6 +40,9 @@ test('main mpv event binder wires callbacks through to runtime deps', () => {
       calls.push(`post-watch:${options?.watchedSeconds ?? 'none'}`);
     },
     logSubtitleTimingError: () => calls.push('subtitle-error'),
+    resolveSubtitleText: (liveText) =>
+      resolvePrimarySubtitleText({ liveText, currentTimeSec: currentTime, cues: seekCues }),
+    getCurrentLiveSubtitleText: () => seekLiveText,
     setCurrentSubText: (text) => calls.push(`set-sub:${text}`),
     getImmediateSubtitlePayload: (text) => ({ text, tokens: [] }),
     broadcastSubtitle: (payload) => calls.push(`broadcast-sub:${payload.text}`),
@@ -60,6 +76,9 @@ test('main mpv event binder wires callbacks through to runtime deps', () => {
     recordMediaDuration: (duration) => calls.push(`duration:${duration}`),
     reportJellyfinRemoteProgress: (forceImmediate) =>
       calls.push(`progress:${forceImmediate ? 'force' : 'normal'}`),
+    onTimePosUpdate: (time) => {
+      currentTime = time;
+    },
     recordPauseState: (paused) => calls.push(`pause:${paused ? 'yes' : 'no'}`),
 
     updateSubtitleRenderMetrics: () => calls.push('subtitle-metrics'),
@@ -83,7 +102,13 @@ test('main mpv event binder wires callbacks through to runtime deps', () => {
   handlers.get('media-path-change')?.({ path: '' });
   handlers.get('media-title-change')?.({ title: 'Episode 1' });
   handlers.get('subtitle-timing')?.({ text: 'timed line', start: 899, end: 901 });
+  handlers.get('subtitle-change')?.({ text: seekLiveText });
+  handlers.get('time-pos-change')?.({ time: 90 });
+  assert.ok(calls.includes('set-sub:少しだけ好きになる'));
+
   handlers.get('time-pos-change')?.({ time: 2.5 });
+  handlers.get('subtitle-change')?.({ text: seekLiveText });
+  handlers.get('time-pos-change')?.({ time: 90 });
   handlers.get('pause-change')?.({ paused: true });
 
   assert.ok(calls.includes('set-sub:line'));

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

@@ -44,6 +44,7 @@ export function createBindMpvMainEventHandlersHandler(deps: {
 
   setCurrentSubText: (text: string) => void;
   resolveSubtitleText?: (text: string) => string;
+  getCurrentLiveSubtitleText?: () => string;
   getImmediateSubtitlePayload?: (text: string) => SubtitleData | null;
   emitImmediateSubtitle?: (payload: SubtitleData) => void;
   broadcastSubtitle: (payload: SubtitleData) => void;
@@ -171,7 +172,14 @@ export function createBindMpvMainEventHandlersHandler(deps: {
       refreshDiscordPresence: () => deps.refreshDiscordPresence(),
       maybeRunAnilistPostWatchUpdate: (options) => deps.maybeRunAnilistPostWatchUpdate(options),
       logError: (message, error) => deps.logSubtitleTimingError(message, error),
-      onTimePosUpdate: (time) => deps.onTimePosUpdate?.(time),
+      onTimePosUpdate: (time, updateKind) => {
+        deps.onTimePosUpdate?.(time);
+        if (updateKind === 'playback') return;
+        const liveText = deps.getCurrentLiveSubtitleText?.();
+        if (liveText !== undefined) {
+          handleMpvSubtitleChange({ text: liveText });
+        }
+      },
     });
     const handleMpvPauseChange = createHandleMpvPauseChangeHandler({
       recordPauseState: (paused) => deps.recordPauseState(paused),

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

@@ -21,6 +21,7 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
     overlayRuntimeInitialized: boolean;
     mpvClient: {
       connected?: boolean;
+      currentSubText?: string;
       currentSecondarySubText?: string;
       currentTimePos?: number;
       requestProperty?: (name: string) => Promise<unknown>;
@@ -160,6 +161,7 @@ export function createBuildBindMpvMainEventHandlersMainDepsHandler(deps: {
         currentTimeSec: Number(deps.appState.mpvClient?.currentTimePos),
         cues: deps.appState.activeParsedSubtitleCues,
       }),
+    getCurrentLiveSubtitleText: () => deps.appState.mpvClient?.currentSubText ?? '',
     recordImmersionSubtitleLine: (text: string, start: number, end: number) => {
       deps.ensureImmersionTrackerInitialized();
       const tracker = deps.appState.immersionTracker;

src/main/runtime/primary-subtitle-text.test.ts

@@ -64,6 +64,30 @@ test('resolvePrimarySubtitleText combines unique simultaneous parsed cues', () =
   );
 });
 
+test('resolvePrimarySubtitleText collapses whitespace variants of one ASS lyric', () => {
+  const ass = [
+    '[Events]',
+    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
+    'Dialogue: 2,0:00:01.00,0:00:03.00,EDJP,,0,0,0,,少しだけ好きになる',
+    'Dialogue: 1,0:00:01.00,0:00:03.00,EDJP,,0,0,0,,少しだけ\\h好きになる',
+    'Dialogue: 0,0:00:01.00,0:00:03.00,EDJP,,0,0,0,,少しだけ　好きになる',
+  ].join('\n');
+  const cues = parseSubtitleCues(ass, 'polar-opposites-s01e10.ass');
+
+  assert.deepEqual(
+    cues.map((cue) => cue.text),
+    ['少しだけ好きになる', '少しだけ 好きになる', '少しだけ　好きになる'],
+  );
+  assert.equal(
+    resolvePrimarySubtitleText({
+      liveText: ['少しだけ好きになる', '少しだけ 好きになる', '少しだけ　好きになる'].join('\n'),
+      currentTimeSec: 2,
+      cues,
+    }),
+    '少しだけ好きになる',
+  );
+});
+
 test('resolvePrimarySubtitleText tolerates stale time-pos at a parsed cue edge', () => {
   assert.equal(
     resolvePrimarySubtitleText({
@@ -184,6 +208,20 @@ test('resolvePrimarySubtitleText combines simultaneous canonical cues in source
   assert.equal(text, 'first\nsecond');
 });
 
+test('resolvePrimarySubtitleText collapses whitespace variants of a canonical lyric', () => {
+  assert.equal(
+    resolvePrimarySubtitleText({
+      liveText: '少しだけ好きになる\n少しだけ　好きになる',
+      currentTimeSec: 2,
+      cues: [
+        { startTime: 1, endTime: 3, text: '少しだけ好きになる', source: 'canonical-ass' },
+        { startTime: 1, endTime: 3, text: '少しだけ　好きになる', source: 'canonical-ass' },
+      ],
+    }),
+    '少しだけ好きになる',
+  );
+});
+
 test('resolveCanonicalPrimarySubtitle covers a nearby generated animation edge', () => {
   const cue = {
     startTime: 1.2,

src/main/runtime/primary-subtitle-text.ts

@@ -25,7 +25,7 @@ function nearbyCanonicalCues(
   currentTimeSec: number,
 ): SubtitleCue[] {
   return (cues ?? []).filter((cue) => {
-    if (cue.source !== 'canonical-ass') {
+    if (cue.source !== 'canonical-ass' && cue.source !== 'reconstructed-ass') {
       return false;
     }
     const span = animationSpan(cue);
@@ -40,6 +40,21 @@ function compactWhitespace(text: string): string {
   return text.replace(/\s+/gu, '');
 }
 
+// ASS layers can encode the same visible spacing with ordinary, hard, or
+// ideographic spaces. Matching and emission must use the same identity or each
+// layer reappears as a copy.
+function uniqueCueTexts(cues: readonly SubtitleCue[]): string[] {
+  const texts: string[] = [];
+  const seen = new Set<string>();
+  for (const cue of cues) {
+    const compactText = compactWhitespace(cue.text);
+    if (seen.has(compactText)) continue;
+    seen.add(compactText);
+    texts.push(cue.text);
+  }
+  return texts;
+}
+
 function compactLineSegments(text: string): string[] {
   return text.split('\n').map(compactWhitespace).filter(Boolean);
 }
@@ -83,14 +98,7 @@ function resolveActiveParsedPrimarySubtitle(options: {
     return null;
   }
 
-  const texts: string[] = [];
-  const seen = new Set<string>();
-  for (const cue of selected) {
-    if (!seen.has(cue.text)) {
-      seen.add(cue.text);
-      texts.push(cue.text);
-    }
-  }
+  const texts = uniqueCueTexts(selected);
   return {
     text: texts.join('\n'),
     startTime: Math.min(...selected.map((cue) => cue.startTime)),
@@ -159,14 +167,7 @@ export function resolveCanonicalPrimarySubtitle(options: {
     return null;
   }
 
-  const texts: string[] = [];
-  const seen = new Set<string>();
-  for (const cue of selected) {
-    if (!seen.has(cue.text)) {
-      seen.add(cue.text);
-      texts.push(cue.text);
-    }
-  }
+  const texts = uniqueCueTexts(selected);
   return {
     text: texts.join('\n'),
     startTime: Math.min(...selected.map((cue) => cue.startTime)),

src/main/runtime/secondary-subtitle-track.test.ts

@@ -20,6 +20,156 @@ test('findActiveSubtitleText combines unique simultaneous parsed cues', () => {
   );
 });
 
+test('findActiveSubtitleText collapses whitespace variants of one ASS lyric', () => {
+  assert.equal(
+    findActiveSubtitleText(
+      [
+        { startTime: 1, endTime: 3, text: '少しだけ好きになる' },
+        { startTime: 1, endTime: 3, text: '少しだけ 好きになる' },
+        { startTime: 1, endTime: 3, text: '少しだけ　好きになる' },
+      ],
+      2,
+    ),
+    '少しだけ好きになる',
+  );
+});
+
+test('parsed secondary lyrics keep explicit ASS vertical order when durations alternate', () => {
+  const lyric = (options: { start: string; end: string; style: string; y: number; text: string }) =>
+    `Dialogue: 0,0:00:${options.start},0:00:${options.end},${options.style},,0,0,0,fx,{\\move(100,${options.y},120,${options.y})\\t(0,200,\\fscx110)}${options.text}\\N{\\p1}m 0 0 l 0 5`;
+  const ass = [
+    '[Events]',
+    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
+    lyric({
+      start: '01.00',
+      end: '02.20',
+      style: 'ed_romaji',
+      y: 66,
+      text: 'ima wo kakusarechau mae ni',
+    }),
+    lyric({
+      start: '01.00',
+      end: '02.00',
+      style: 'ed_english',
+      y: 1020,
+      text: 'Before the present moment gets hidden away.',
+    }),
+    lyric({
+      start: '03.00',
+      end: '04.00',
+      style: 'ed_romaji',
+      y: 66,
+      text: 'ame mitai ni hikatteru',
+    }),
+    lyric({
+      start: '03.00',
+      end: '04.20',
+      style: 'ed_english',
+      y: 1020,
+      text: 'Is shining like rain.',
+    }),
+  ].join('\n');
+  const cues = parseSubtitleCues(ass, 'polar-opposites-s01e08.ass');
+
+  assert.equal(
+    findActiveSubtitleText(cues, 1.5),
+    'ima wo kakusarechau mae ni\nBefore the present moment gets hidden away.',
+  );
+  assert.equal(findActiveSubtitleText(cues, 3.5), 'ame mitai ni hikatteru\nIs shining like rain.');
+});
+
+test('unpositioned secondary lyrics fall back to ASS source order', () => {
+  const ass = [
+    '[Events]',
+    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
+    'Dialogue: 0,0:00:01.00,0:00:02.20,ED Romaji,,0,0,0,,ima wo kakusarechau mae ni',
+    'Dialogue: 0,0:00:01.00,0:00:02.00,ED English,,0,0,0,,Before the present moment gets hidden away.',
+  ].join('\n');
+
+  assert.equal(
+    findActiveSubtitleText(parseSubtitleCues(ass, 'ending.ass'), 1.5),
+    'ima wo kakusarechau mae ni\nBefore the present moment gets hidden away.',
+  );
+});
+
+test('findActiveSubtitleText keeps a canonical ASS cue for its generated animation span', () => {
+  const poof = {
+    startTime: 1110.67,
+    endTime: 1110.71,
+    text: 'POOF',
+    source: 'canonical-ass' as const,
+    animationStartTime: 1110.67,
+    animationEndTime: 1111.59,
+  };
+
+  assert.equal(findActiveSubtitleText([poof], 1111.58), 'POOF');
+  assert.equal(findActiveSubtitleText([poof], 1111.59), '');
+});
+
+test('ASS fragment karaoke stays separated by style with authored word spacing', () => {
+  const lineEvents = (
+    style: string,
+    fragments: readonly string[],
+    y: number,
+    baseTime = 1,
+  ): string[] => {
+    const events: string[] = [];
+    for (const layer of [0, 1]) {
+      fragments.forEach((fragment, index) => {
+        const x = 100 + index * 40;
+        const start = (baseTime + index * 0.25).toFixed(2).padStart(5, '0');
+        const end = (baseTime + 3 + index * 0.2).toFixed(2).padStart(5, '0');
+        events.push(
+          `Dialogue: ${layer},0:00:${start},0:00:${end},${style},,0,0,0,,{\\pos(${x},${y})\\t(0,200,\\fscx110)}${fragment}\\N{\\p1}m 0 0 l 0 10`,
+        );
+      });
+    }
+    return events;
+  };
+  const ass = [
+    '[Events]',
+    'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
+    ...lineEvents('ed_romaji', ['ji', 'gu', 'za', 'gu ', 'na', 'mi'], 70),
+    ...lineEvents('ed_english', ['Pas', 'si', 'ng ', 'thro', 'u', 'gh '], 110),
+    ...lineEvents('op_english', ['I', 'want', 'to', 'go'], 110, 7),
+  ].join('\n');
+
+  assert.equal(
+    findActiveSubtitleText(parseSubtitleCues(ass, 'ending.ass'), 2.5),
+    'jiguzagu nami\nPassing through',
+  );
+  // Some generated scripts discard spaces and retain only positioned chunks. Joining
+  // without invented separators avoids turning one word into spaced syllables.
+  assert.equal(findActiveSubtitleText(parseSubtitleCues(ass, 'ending.ass'), 8.5), 'Iwanttogo');
+});
+
+test('findActiveSubtitleText keeps a complete reconstructed line over entrance fragments', () => {
+  const current = {
+    startTime: 1,
+    endTime: 4,
+    text: 'Complete current line',
+    source: 'reconstructed-ass' as const,
+    assStyle: 'op_english',
+  };
+  const nextEntrance = {
+    startTime: 3.8,
+    endTime: 4.2,
+    text: 'Ne',
+    source: 'reconstructed-ass' as const,
+    assStyle: 'op_english',
+  };
+  const nextLine = {
+    startTime: 4,
+    endTime: 7,
+    text: 'Next complete line',
+    source: 'reconstructed-ass' as const,
+    assStyle: 'op_english',
+  };
+
+  assert.equal(findActiveSubtitleText([current, nextEntrance], 3.9), current.text);
+  assert.equal(findActiveSubtitleText([current, nextEntrance, nextLine], 4.1), nextLine.text);
+});
+
 test('secondary track controller parses the selected ASS file before publishing', async () => {
   const broadcasts: string[] = [];
   let currentText = '';

src/main/runtime/secondary-subtitle-track.ts

@@ -58,16 +58,102 @@ function buildSelectedTrackIdentity(
   ]);
 }
 
+type IndexedSubtitleCue = { cue: SubtitleCue; index: number };
+
+function compareAuthoredSubtitleOrder(left: IndexedSubtitleCue, right: IndexedSubtitleCue): number {
+  const leftLayout = left.cue.assLayout;
+  const rightLayout = right.cue.assLayout;
+  if (leftLayout?.kind === 'positioned' && rightLayout?.kind === 'positioned') {
+    const verticalOrder = leftLayout.y - rightLayout.y;
+    if (verticalOrder !== 0) return verticalOrder;
+  }
+  if (leftLayout && rightLayout) {
+    const sourceOrder = leftLayout.sourceOrder - rightLayout.sourceOrder;
+    if (sourceOrder !== 0) return sourceOrder;
+  }
+  return left.index - right.index;
+}
+
 export function findActiveSubtitleText(cues: readonly SubtitleCue[], timeSeconds: number): string {
   if (!Number.isFinite(timeSeconds)) return '';
 
+  const authoredCanonical = cues.filter(
+    (cue) =>
+      cue.source === 'canonical-ass' && cue.startTime <= timeSeconds && cue.endTime > timeSeconds,
+  );
+  const selectedCanonical = new Set<SubtitleCue>(authoredCanonical);
+  if (selectedCanonical.size === 0) {
+    const animatedCanonical = cues.filter(
+      (cue) =>
+        cue.source === 'canonical-ass' &&
+        (cue.animationStartTime ?? cue.startTime) <= timeSeconds &&
+        (cue.animationEndTime ?? cue.endTime) > timeSeconds,
+    );
+    const nearestDistance = animatedCanonical.reduce((nearest, cue) => {
+      const distance =
+        timeSeconds < cue.startTime
+          ? cue.startTime - timeSeconds
+          : Math.max(0, timeSeconds - cue.endTime);
+      return Math.min(nearest, distance);
+    }, Infinity);
+    for (const cue of animatedCanonical) {
+      const distance =
+        timeSeconds < cue.startTime
+          ? cue.startTime - timeSeconds
+          : Math.max(0, timeSeconds - cue.endTime);
+      if (distance === nearestDistance) {
+        selectedCanonical.add(cue);
+      }
+    }
+  }
+
+  const activeReconstructed = cues.filter(
+    (cue) =>
+      cue.source === 'reconstructed-ass' &&
+      cue.startTime <= timeSeconds &&
+      cue.endTime > timeSeconds,
+  );
+  const reconstructedByStyle = new Map<string, SubtitleCue>();
+  for (const cue of activeReconstructed) {
+    const style = cue.assStyle ?? '';
+    const existing = reconstructedByStyle.get(style);
+    if (!existing) {
+      reconstructedByStyle.set(style, cue);
+      continue;
+    }
+    const duration = cue.endTime - cue.startTime;
+    const existingDuration = existing.endTime - existing.startTime;
+    if (
+      duration > existingDuration ||
+      (duration === existingDuration && cue.text.length > existing.text.length) ||
+      (duration === existingDuration &&
+        cue.text.length === existing.text.length &&
+        cue.startTime > existing.startTime)
+    ) {
+      reconstructedByStyle.set(style, cue);
+    }
+  }
+  const selectedReconstructed = new Set(reconstructedByStyle.values());
+
   const seen = new Set<string>();
   const activeText: string[] = [];
-  for (const cue of cues) {
-    if (cue.startTime > timeSeconds || cue.endTime <= timeSeconds) continue;
+  const activeCues: IndexedSubtitleCue[] = [];
+  cues.forEach((cue, index) => {
+    const active =
+      cue.source === 'canonical-ass'
+        ? selectedCanonical.has(cue)
+        : cue.source === 'reconstructed-ass'
+          ? selectedReconstructed.has(cue)
+          : cue.startTime <= timeSeconds && cue.endTime > timeSeconds;
+    if (active) activeCues.push({ cue, index });
+  });
+  activeCues.sort(compareAuthoredSubtitleOrder);
+
+  for (const { cue } of activeCues) {
     const text = cue.text.trim();
-    if (!text || seen.has(text)) continue;
-    seen.add(text);
+    const compactText = text.replace(/\s+/gu, '');
+    if (!compactText || seen.has(compactText)) continue;
+    seen.add(compactText);
     activeText.push(text);
   }
   return activeText.join('\n');