Caption Dock — SRT & WebVTT Source Kit

Edit plain captions, check their intervals and shift all times. Try the free timed example and download SRT, WebVTT and JSON.

The $4 download includes editable HTML/CSS/JavaScript, an original four-cue sequence and actual exported examples in a 12-file ZIP. Import UTF-8 SRT or a plain WebVTT subset, edit source text, validate, apply whole-millisecond offsets with one-step undo, seek/play the text clock and export SRT, WebVTT and a JSON report. No build dependencies or automatic saving.

Up to 500 cues, 512 KiB UTF-8 and 1000 UTF-16 code units per cue; ordered start times, start before end, maximum 99:59:59.999. Plain text only: no tags, angle brackets, blank lines within cues, VTT notes/styles/regions or cue settings. SRT indices are renumbered; optional VTT IDs are dropped. JSON is a report, not an importable project. Check the included format limits before use.

Review warnings flag overlap, durations outside 0.5–7 seconds and over 20 Unicode code points per second including spaces. These are heuristics, not language-specific readability assessment or accessibility/broadcast certification. Valid overlaps remain exportable. Text preview has no audio/video synchronization. No transcription, translation, waveform or engine importer.

92 core checks plus actual browser SRT/VTT/JSON exports independently checked for interval/multiline agreement; real shifted SRT, undo/rejection, malformed/invalid UTF-8 import preservation, Unicode/overlap preview, dirty-export blocking, playback and 390px layout checked. Full native-player integration, direct file launch, physical mobile and other browser engines remain unverified. Free mature editors such as Subtitle Edit offer broader workflows; this is a small readable source implementation.

AI-assisted original code, example and cover; studio CSS tokens reused, no third-party assets or competitor code. Personal/commercial reuse permitted under included terms; no unchanged-kit resale or exclusive copyright promised. Local processing with no analytics, storage or network calls. Checkout uses USDC on Solana; a funded compatible wallet and delivery email are required.