webcvtConvert files in the browser

Browser-first, hardware-accelerated, 5-500 KB modular library. No upload required.

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Browser-first

Designed for the browser, with Node.js and Cloudflare Workers reusing the same code. Same API everywhere.

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WebCodecs first; ffmpeg.wasm fallback only when needed. Get the best performance the device can offer.

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npm i @catlabtech/webcvt-container-mp3 if you only want MP3. No 30 MB blob. 22 packages — import only what you need.

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Proper types throughout. Autocomplete works, end-to-end type safety from input format to output blob.

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Files stay on the user's device by default. No server, no upload, no data leaving the browser.

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AV containers, archives, subtitles, data-text — all self-written. No runtime npm dependencies in core.