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v0.6.0 — Format extensions

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@SteliyanH SteliyanH released this 21 May 22:24
· 11 commits to main since this release
v0.6.0
83a09c0

Format extensions. Reopened cycle (v0.5 was marked feature-complete) to close the niche-but-real ingest gaps that have come up in downstream pipelines and bring the API in line with the modern VTT spec. Three additions, all additive — every v0.5 call site compiles unchanged.

Added — VobSub .idx parser (Tier 1)

  • VobSubIndex + VobSubCue Sendable structs — language + 16-entry palette + array of cues (start time + byte offset into the paired .sub file).
  • CaptionParser.parseVobSubIndex(_:) + pure helpers (parseVobSubLanguage, parseVobSubPalette, parseVobSubTimestamp). Timestamp uses HH:MM:SS:mmm colon format — strictly rejects SRT-comma / VTT-dot variants.
  • Caption.fromVobSubIndex(_:placeholderText:trailingDuration:) — bridge that renders the index as [Caption] with placeholder text. Cue duration inferred from gap to next cue; last cue uses caller-supplied trailing duration (the format has no end-time field).
  • Bitmap extraction from the paired .sub file is a v0.7 follow-up — v0.6 surfaces the index timing only so consumers can mark subtitle existence in the timeline.

Added — WebVTT cue regions (Tier 2)

  • CaptionRegion + RegionScrollMode types — id, widthPercent, lines, region/viewport anchors (normalized 0...1 per axis), scroll mode. Defaults align with WebVTT spec.
  • StyledCaption.region: CaptionRegion? — additive, default nil. v0.5 styled-caption call sites compile unchanged.
  • parseStyledVTT(_:) now collects REGION blocks (instead of skipping) and resolves region:NAME cue references. Unknown ids resolve to nil — tolerates authoring tools that strip regions mid-pipeline.
  • Pure helpers: parseStyledVTTRegionBlock(_:) + parseVTTRegionID(_:).
  • Plain parseVTT(_:) unchanged — regions stay styled-only.

Added — EBU-TT-D parser (Tier 3)

  • CaptionParser.parseEBUTTD(_:) + Caption.load(ebuTTD:) — string + disk parsers for the European broadcast TTML profile (EBU Tech 3380).
  • CaptionParser.parseEBUTTDTime(_:) pure time helper. Accepts HH:MM:SS and HH:MM:SS.mmm only; rejects iTT's frame-count form (HH:MM:SS:FF) and TTML's suffix forms (1.5s, 1500ms). EBU profile mandates clock-form timing.
  • Plain text only — styled EBU-TT-D's region-nested layout is a future-cycle candidate. <br/> inserts newlines; <ebuttm:documentMetadata> and <ebutts:style> head blocks silently skipped.
  • No Caption.load(_:) extension switch entry — .xml / .ttml are ambiguous with other TTML profiles. Consumers call load(ebuTTD:) directly.

Tests

39 new tests across the cycle. Highlights: cross-format strictness pins (VobSub rejects SRT-comma timing; EBU-TT-D rejects iTT frame-count timing), region resolution edge cases (referenced / unreferenced / ghost id / multi-region), <br/> newline insertion, head metadata skipping. XCTest suite: 43 → 82.

Dependencies

No floor bumps. Still requires kadr ≥ 0.9.2.

Assets 2
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