Remove duplicate caption builders

[natashaannn]

Remove duplicate caption builders

Objective

Ensure only one canonical caption builder exists in Remotion.

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Why this matters

Caption divergence causes subtle render mismatches across overlays.

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Parallelization metadata

Track

remotion

Depends on

• Extract shared captions utility #44

Safe to run in parallel with

• pipeline validation

Merge risk

• low/medium

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Files in scope

Primary:

• remotion/lib/captions.ts

Likely touch:

• HookOverlay.tsx
• CaptionOverlay.tsx

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Required implementation

1. Remove duplicates

Ensure all caption logic imports shared utility.

2. Normalize exports

Single API surface.

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Constraints

• no visual changes

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Acceptance criteria

Functional

• captions identical to baseline output

Regression checks

• no local caption logic remains

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Verification commands

grep -r "buildCaptions" remotion/

Expected result:

• only one implementation exists

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Explicitly out of scope

• new caption features

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Suggested branch

refactor/s7-caption-cleanup

Suggested commit slug

phase-5-step-6-captions-cleanup