io.github.Ishaan-Gpt/captionseasy

What it does

Drop a video, get word-timed animated captions in a couple of minutes, fix any word, pick a look, export an MP4.

• Runs in your browser. Speech recognition is Whisper running on WebGPU / WASM in your tab (transformers.js). Rendering is the same Remotion composition the preview uses, encoded with WebCodecs. Your video is never uploaded.
• 20+ looks — Hormozi box, karaoke fill, neon, glow, comic, retro 3D, serif accents and more. Every look renders identically in the preview and the export.
• Edit everything — words, timing, line breaks, key words, position, fonts (400+ Google fonts or your own), colours, motion.
• Hindi / Hinglish in Roman script with a fine-tuned Whisper model (Oriserve Whisper-Hindi2Hinglish-Swift, converted to ONNX with word timestamps).
• Exports: MP4 with burned-in captions, SRT. The optional desktop helper adds transparent overlays (ProRes 4444 / WebM alpha) for Premiere, Resolve and CapCut.
• No signup to try, no watermark.

Tech stack

Web app + API	Next.js 16, React 19, Tailwind 4 (apps/frontend)
Captions rendering	Remotion — @remotion/player for preview, @remotion/web-renderer for in-browser MP4
Speech to text	Whisper via transformers.js (WebGPU, WASM fallback)
Media	Mediabunny for probing, decoding and converting in the browser
Data & auth	Supabase (Postgres + RLS, Auth)
Hosting	Vercel

Repository layout

apps/frontend            Next.js app: landing, studio, API routes (/api/v1)
packages/shared          zod contracts shared by app, engine and helper
packages/caption-engine  pure TypeScript: normalize ASR words, segment into cards, SRT/VTT/ASS export
packages/templates       caption layouts, looks, motion library, fonts
packages/compositions    the Remotion composition used by both preview and export
packages/companion       optional desktop helper (local whisper.cpp + Remotion renderer)
supabase/migrations      database migrations

Run it locally

Requirements: Node 20+, pnpm, a free Supabase project.

git clone https://github.com/Ishaan-Gpt/Captions-Easy.git
cd Captions-Easy
pnpm install
cp apps/frontend/.env.example apps/frontend/.env.local   # fill in your Supabase keys
pnpm dev                                                 # http://localhost:3000

Checks:

pnpm typecheck
pnpm test
pnpm build

Database: supabase/migrations currently holds the later migrations only; a full schema snapshot is on the way. Until then, open an issue if you want to self-host and we'll help.

Licensing

CaptionsEasy's own code is MIT.

It is built on Remotion, which has its own license: free for individuals and small teams, but companies above Remotion's free tier need a Remotion company license to use it. If you fork CaptionsEasy for a business, check Remotion's terms.

Fonts and speech models keep their own licenses (Google Fonts: OFL / Apache; Whisper models: MIT / Apache-2.0).

Contributing

Issues and PRs are welcome — see CONTRIBUTING.md. Good first areas: new caption looks, language support, editor polish.

If CaptionsEasy saved you time, a ⭐ helps a lot.

Made by Ishaan Gupta.