fix(subtitles): drop ASS furigana from published cues (#224)

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

@@ -1442,7 +1442,7 @@ const eventsHeader = [
   'Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text',
 ];
 
-test('parseSubtitleCues keeps a tall CC-style dialogue block publishable, not a fragment grid', () => {
+test('parseSubtitleCues keeps tall CC-style base dialogue publishable after removing furigana', () => {
   const content = [
     ...eventsHeader,
     'Dialogue: 0,0:00:06.11,0:00:10.11,Default,,0,0,0,,{\\pos(212,383)\\fscx50\\fscy50}たき',
@@ -1451,9 +1451,94 @@ test('parseSubtitleCues keeps a tall CC-style dialogue block publishable, not a
     'Dialogue: 0,0:00:06.11,0:00:10.11,Default,,0,0,0,,{\\pos(192,497)}お前…{\\fscx50}　{\\fscx100}燈をバンドに誘ったの？',
   ].join('\n');
 
-  const cue = parseSubtitleCues(content, 'test.ass')[0];
-  assert.equal(cue?.text, 'たき（立希）ともりお前…　燈をバンドに誘ったの？');
-  assert.equal(cue?.assLayout?.kind, 'positioned');
+  const cues = parseSubtitleCues(content, 'test.ass');
+  assert.deepEqual(
+    cues.map((cue) => cue.text),
+    ['（立希）', 'お前…　燈をバンドに誘ったの？'],
+  );
+  assert.deepEqual(cues[0]?.assFurigana, ['たき']);
+  assert.deepEqual(cues[1]?.assFurigana, ['ともり']);
+  assert.ok(cues.every((cue) => cue.assLayout?.kind === 'positioned'));
+});
+
+test('parseSubtitleCues removes half-size positioned furigana from broadcast captions', () => {
+  const content = [
+    '[Script Info]',
+    'PlayResY: 540',
+    '',
+    ...eventsHeader,
+    'Dialogue: 0,0:02:38.20,0:02:41.87,Default,,0,0,0,,{\\pos(192,77)\\fscx50}（{\\fscx100}山田{\\fscx50}）{\\fscx100}ごめん{\\fscx50}　{\\fscx100}結局{\\fscx50}　{\\fscx100}ぬれたな{\\fscx50}。',
+    'Dialogue: 0,0:02:38.20,0:02:41.87,Default,,0,0,0,,{\\pos(552,113)\\fscx50\\fscy50}だいじょうぶ',
+    'Dialogue: 0,0:02:38.20,0:02:41.87,Default,,0,0,0,,{\\pos(552,167)}大丈夫{\\fscx50}。',
+    'Dialogue: 0,0:03:51.34,0:03:53.68,Default,,0,0,0,,{\\pos(232,407)\\fscx50}（{\\fscx100}山田の母{\\fscx50}）{\\fscx100}ほんなら',
+    'Dialogue: 0,0:03:51.34,0:03:53.68,Default,,0,0,0,,{\\pos(232,443)\\fscx50\\fscy50}かく',
+    'Dialogue: 0,0:03:51.34,0:03:53.68,Default,,0,0,0,,{\\pos(312,443)\\fscx50\\fscy50}ちょぞう',
+    'Dialogue: 0,0:03:51.34,0:03:53.68,Default,,0,0,0,,{\\pos(232,497)}隠し貯蔵のミルクまんじゅう➡',
+    'Dialogue: 0,0:04:00.00,0:04:03.00,Default,,0,0,0,,{\\pos(232,443)\\fscx50\\fscy50}ぜったい　ちが',
+    'Dialogue: 0,0:04:00.00,0:04:03.00,Default,,0,0,0,,{\\pos(232,497)}絶対違う',
+  ].join('\n');
+
+  const cues = parseSubtitleCues(content, 'polar-opposites-s02e08.ass');
+
+  assert.deepEqual(
+    cues.map((cue) => cue.text),
+    [
+      '（山田）ごめん　結局　ぬれたな。',
+      '大丈夫。',
+      '（山田の母）ほんなら',
+      '隠し貯蔵のミルクまんじゅう➡',
+      '絶対違う',
+    ],
+  );
+  assert.deepEqual(cues[1]?.assFurigana, ['だいじょうぶ']);
+  assert.deepEqual(cues[3]?.assFurigana, ['かく', 'ちょぞう']);
+  assert.deepEqual(cues[4]?.assFurigana, ['ぜったい　ちが']);
+});
+
+test('parseSubtitleCues scales furigana geometry by PlayResY', () => {
+  const content = [
+    '[Script Info]',
+    'PlayResY: 1080',
+    '',
+    ...eventsHeader,
+    'Dialogue: 0,0:02:38.20,0:02:41.87,Default,,0,0,0,,{\\pos(1104,226)\\fscx50\\fscy50}だいじょうぶ',
+    'Dialogue: 0,0:02:38.20,0:02:41.87,Default,,0,0,0,,{\\pos(1104,334)}大丈夫{\\fscx50}。',
+  ].join('\n');
+
+  const cues = parseSubtitleCues(content, 'test.ass');
+  assert.deepEqual(
+    cues.map((cue) => cue.text),
+    ['大丈夫。'],
+  );
+  assert.deepEqual(cues[0]?.assFurigana, ['だいじょうぶ']);
+});
+
+test('parseSubtitleCues preserves small kana without a matching kanji base caption', () => {
+  const content = [
+    ...eventsHeader,
+    'Dialogue: 0,0:00:01.00,0:00:04.00,Default,,0,0,0,,{\\pos(200,200)\\fscx50\\fscy50}ひそひそ',
+    'Dialogue: 0,0:00:01.00,0:00:04.00,Default,,0,0,0,,{\\pos(200,254)}ordinary dialogue',
+  ].join('\n');
+
+  assert.deepEqual(
+    parseSubtitleCues(content, 'test.ass').map((cue) => cue.text),
+    ['ひそひそ', 'ordinary dialogue'],
+  );
+});
+
+test('parseSubtitleCues preserves small kana horizontally separated from a kanji caption', () => {
+  const content = [
+    ...eventsHeader,
+    'Dialogue: 0,0:00:01.00,0:00:04.00,Default,,0,0,0,,{\\pos(800,200)\\fscx50\\fscy50}ひそひそ',
+    'Dialogue: 0,0:00:01.00,0:00:04.00,Default,,0,0,0,,{\\pos(200,254)}漢字',
+  ].join('\n');
+
+  const cues = parseSubtitleCues(content, 'test.ass');
+  assert.match(cues.map((cue) => cue.text).join('\n'), /ひそひそ/);
+  assert.deepEqual(
+    cues.flatMap((cue) => cue.assFurigana ?? []),
+    [],
+  );
 });
 
 test('parseSubtitleCues marks re-shown countdown frames as a fragment grid', () => {

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

@@ -14,7 +14,13 @@ import { hasAssAnimationEvidence, mergeDuplicateCues } from './subtitle-cue-dedu
 export type AssVerticalBand = 'top' | 'middle' | 'bottom';
 
 export type AssCueLayout =
-  | { kind: 'positioned'; sourceOrder: number; y: number; verticalBand?: AssVerticalBand }
+  | {
+      kind: 'positioned';
+      sourceOrder: number;
+      x?: number;
+      y: number;
+      verticalBand?: AssVerticalBand;
+    }
   | { kind: 'fragment-grid'; sourceOrder: number; verticalBand?: AssVerticalBand }
   | { kind: 'source-order'; sourceOrder: number; verticalBand?: AssVerticalBand };
 
@@ -22,6 +28,11 @@ export interface SubtitleCue {
   startTime: number;
   endTime: number;
   text: string;
+  /**
+   * ASS ruby text removed from the published cue. Kept only so live `sub-text` matching
+   * can account for the extra lines mpv still reports from the source track.
+   */
+  assFurigana?: readonly string[];
   /** How a complete line was recovered from generated ASS animation events. */
   source?: 'canonical-ass' | 'reconstructed-ass';
   /**
@@ -100,10 +111,17 @@ function sanitizeAssCueText(text: string): string {
   return removeAssControlDebrisLines(decodeSubtitleCueText(text)).trim();
 }
 
-function attachAssLayout<T extends SubtitleCue>(cue: T, assLayout: AssCueLayout | undefined): T {
+function attachAssMetadata<T extends SubtitleCue>(
+  cue: T,
+  assLayout: AssCueLayout | undefined,
+  assFurigana: readonly string[] | undefined,
+): T {
   if (assLayout) {
     Object.defineProperty(cue, 'assLayout', { value: assLayout, enumerable: false });
   }
+  if (assFurigana?.length) {
+    Object.defineProperty(cue, 'assFurigana', { value: assFurigana, enumerable: false });
+  }
   return cue;
 }
 
@@ -118,6 +136,7 @@ function toPublicCues(cues: AnnotatedSubtitleCue[]): SubtitleCue[] {
       animationEndTime,
       style,
       assLayout,
+      assFurigana,
     }) => {
       const common = {
         startTime,
@@ -125,7 +144,7 @@ function toPublicCues(cues: AnnotatedSubtitleCue[]): SubtitleCue[] {
         text,
       };
       if (source === 'reconstructed-ass') {
-        return attachAssLayout(
+        return attachAssMetadata(
           {
             ...common,
             source,
@@ -134,11 +153,13 @@ function toPublicCues(cues: AnnotatedSubtitleCue[]): SubtitleCue[] {
             assStyle: style,
           },
           assLayout,
+          assFurigana,
         );
       }
-      return attachAssLayout(
+      return attachAssMetadata(
         source ? { ...common, source, animationStartTime, animationEndTime } : common,
         assLayout,
+        assFurigana,
       );
     },
   );
@@ -2019,6 +2040,9 @@ function recoverCanonicalAssEvents({
     const animationEndTime = latestEndTime(generatedEvents, candidate.endTime);
     const startTime = kind === 'comment' ? candidate.startTime : animationStartTime;
     const endTime = kind === 'comment' ? candidate.endTime : animationEndTime;
+    const assFurigana = [
+      ...new Set([candidate, ...generatedEvents].flatMap((cue) => cue.assFurigana ?? [])),
+    ];
     const recoveredCue: AnnotatedSubtitleCue = {
       ...candidate,
       startTime,
@@ -2026,6 +2050,7 @@ function recoverCanonicalAssEvents({
       animationStartTime,
       animationEndTime,
       source: 'canonical-ass',
+      ...(assFurigana.length === 0 ? {} : { assFurigana }),
     };
     recovered.push(recoveredCue);
     recoveredByOwner.set(candidate, recoveredCue);
@@ -2170,34 +2195,156 @@ function buildAssCueLayout(
   style: string,
   placement: AssPlacementContext,
 ): AssCueLayout {
+  let x: number | null = null;
   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') {
+      x = parseAssCoordinate(args[0]) ?? x;
       y = parseAssCoordinate(args[1]) ?? y;
       continue;
     }
     if (name !== 'move') continue;
+    const startX = parseAssCoordinate(args[0]);
     const startY = parseAssCoordinate(args[1]);
+    const endX = parseAssCoordinate(args[2]);
     const endY = parseAssCoordinate(args[3]);
+    if (startX !== null && endX !== null) {
+      x = (startX + endX) / 2;
+    }
     if (startY !== null && endY !== null) {
       y = (startY + endY) / 2;
     }
   }
   const verticalBand = resolveVerticalBand(overrides, y, style, placement);
   const base: AssCueLayout =
-    y === null ? { kind: 'source-order', sourceOrder } : { kind: 'positioned', sourceOrder, y };
+    y === null
+      ? { kind: 'source-order', sourceOrder }
+      : { kind: 'positioned', sourceOrder, ...(x === null ? {} : { x }), y };
   return verticalBand ? { ...base, verticalBand } : base;
 }
 
-function parseAnnotatedAssEvents(content: string): ParsedAssEvents {
+const ASS_FURIGANA_TEXT_PATTERN = /^[\p{Script=Hiragana}\p{Script=Katakana}ー・ \t\u3000]+$/u;
+const ASS_KANJI_PATTERN = /\p{Script=Han}/u;
+const MAX_ASS_FURIGANA_SCALE_PERCENT = 60;
+// The pixel geometry below is authored in the 540-line coordinate space Caption2Ass-style
+// broadcast CC converters emit, and is multiplied by PlayResY/540 so the same on-screen
+// window applies to scripts declaring other resolutions. Without a declaration the tuned
+// space is assumed.
+const ASS_FURIGANA_REFERENCE_PLAY_RES_Y = 540;
+const MIN_ASS_FURIGANA_BASE_GAP = 40;
+const MAX_ASS_FURIGANA_BASE_GAP = 68;
+const MIN_ASS_FURIGANA_HORIZONTAL_TOLERANCE = 80;
+const ASS_BASE_CHARACTER_WIDTH_ESTIMATE = 40;
+
+function assFuriganaGeometryScale(playResY: number | null): number {
+  return playResY && playResY > 0 ? playResY / ASS_FURIGANA_REFERENCE_PLAY_RES_Y : 1;
+}
+
+function staticAssScalePercent(cue: AnnotatedSubtitleCue, axis: 'fscx' | 'fscy'): number | null {
+  let scale: number | null = null;
+  for (const command of cue.overrides) {
+    if (command.animated || command.name.toLowerCase() !== axis) continue;
+    const value = Number(command.args.trim());
+    if (Number.isFinite(value) && value > 0) {
+      scale = value;
+    }
+  }
+  return scale;
+}
+
+function isAssFuriganaCandidate(cue: AnnotatedSubtitleCue): boolean {
+  const scaleX = staticAssScalePercent(cue, 'fscx');
+  const scaleY = staticAssScalePercent(cue, 'fscy');
+  return (
+    cue.assLayout?.kind === 'positioned' &&
+    ASS_FURIGANA_TEXT_PATTERN.test(cue.text) &&
+    scaleX !== null &&
+    scaleX <= MAX_ASS_FURIGANA_SCALE_PERCENT &&
+    scaleY !== null &&
+    scaleY <= MAX_ASS_FURIGANA_SCALE_PERCENT
+  );
+}
+
+function findAssFuriganaBase(
+  furigana: AnnotatedSubtitleCue,
+  cues: readonly AnnotatedSubtitleCue[],
+  geometryScale: number,
+): AnnotatedSubtitleCue | null {
+  if (furigana.assLayout?.kind !== 'positioned' || furigana.assLayout.x === undefined) {
+    return null;
+  }
+
+  let nearest: { cue: AnnotatedSubtitleCue; gap: number } | null = null;
+  for (const cue of cues) {
+    if (
+      cue === furigana ||
+      cue.startTime !== furigana.startTime ||
+      cue.endTime !== furigana.endTime ||
+      cue.style !== furigana.style ||
+      cue.layer !== furigana.layer ||
+      cue.name !== furigana.name ||
+      cue.assLayout?.kind !== 'positioned' ||
+      !ASS_KANJI_PATTERN.test(cue.text)
+    ) {
+      continue;
+    }
+    const scaleY = staticAssScalePercent(cue, 'fscy');
+    if (scaleY !== null && scaleY <= MAX_ASS_FURIGANA_SCALE_PERCENT) continue;
+
+    const gap = cue.assLayout.y - furigana.assLayout.y;
+    if (
+      gap < MIN_ASS_FURIGANA_BASE_GAP * geometryScale ||
+      gap > MAX_ASS_FURIGANA_BASE_GAP * geometryScale
+    ) {
+      continue;
+    }
+    if (cue.assLayout.x === undefined) continue;
+    const baseCharacterCount = [...cue.text.replace(/[ \t\u3000]/g, '')].length;
+    const horizontalTolerance =
+      Math.max(
+        MIN_ASS_FURIGANA_HORIZONTAL_TOLERANCE,
+        baseCharacterCount * ASS_BASE_CHARACTER_WIDTH_ESTIMATE,
+      ) * geometryScale;
+    if (Math.abs(cue.assLayout.x - furigana.assLayout.x) > horizontalTolerance) continue;
+    if (!nearest || gap < nearest.gap || (gap === nearest.gap && cue.order < nearest.cue.order)) {
+      nearest = { cue, gap };
+    }
+  }
+  return nearest?.cue ?? null;
+}
+
+function removeAssFuriganaFromCueList(
+  cues: AnnotatedSubtitleCue[],
+  geometryScale: number,
+): AnnotatedSubtitleCue[] {
+  const removed = new Set<AnnotatedSubtitleCue>();
+  for (const cue of cues) {
+    if (!isAssFuriganaCandidate(cue)) continue;
+    const base = findAssFuriganaBase(cue, cues, geometryScale);
+    if (!base) continue;
+    base.assFurigana = [...new Set([...(base.assFurigana ?? []), cue.text])];
+    removed.add(cue);
+  }
+  return removed.size === 0 ? cues : cues.filter((cue) => !removed.has(cue));
+}
+
+function removeAssFuriganaEvents(
+  events: ParsedAssEvents,
+  playResY: number | null,
+): ParsedAssEvents {
+  const geometryScale = assFuriganaGeometryScale(playResY);
+  return {
+    dialogue: removeAssFuriganaFromCueList(events.dialogue, geometryScale),
+    comments: removeAssFuriganaFromCueList(events.comments, geometryScale),
+  };
+}
+
+function parseAnnotatedAssEvents(content: string, placement: AssPlacementContext): ParsedAssEvents {
   const cues: AnnotatedSubtitleCue[] = [];
   const comments: AnnotatedSubtitleCue[] = [];
-  const placement = content.includes('[')
-    ? parseAssPlacementContext(content)
-    : EMPTY_PLACEMENT_CONTEXT;
   const lines = content.split(/\r?\n/);
   let inEventsSection = false;
   let eventOrder = 0;
@@ -2322,7 +2469,13 @@ function parseAnnotatedAssEvents(content: string): ParsedAssEvents {
 }
 
 function parseAnnotatedAssCues(content: string): AnnotatedSubtitleCue[] {
-  const events = removeAssFontTextureEvents(parseAnnotatedAssEvents(content));
+  const placement = content.includes('[')
+    ? parseAssPlacementContext(content)
+    : EMPTY_PLACEMENT_CONTEXT;
+  const events = removeAssFuriganaEvents(
+    removeAssFontTextureEvents(parseAnnotatedAssEvents(content, placement)),
+    placement.playResY,
+  );
   return recoverFragmentOnlyAssLines(recoverCanonicalAssEvents(events));
 }