WHAT IS IT?
A video editor that runs entirely in the browser, built on ffmpeg.wasm (FFmpeg compiled to WebAssembly). Files never leave your machine: processing happens in a Web Worker, with no upload and no backend. Despite the name, the interface exposes over 30 ready-to-use operations (conversion, trimming, GIF creation, automatic captioning...); the raw command line is just one mode among them.
WHY IS IT INTERESTING?
- Everything runs locally: FFmpeg executes in WebAssembly inside a Web Worker. No data is sent to any server, nothing is collected, and the UI stays responsive during encoding.
- 30+ operations: MP4/WebM/MKV/MOV/AVI conversion, compression, trimming, cropping, GIF creation, audio extraction, concatenation, picture-in-picture, denoise, audio normalization, among others.
- Automatic captions: Whisper transcription also runs in the browser via Transformers.js, with a choice between hard-burned subtitles or an embedded track.
- Stack mode and batch: compatible filters chain into a single encoding pass, so quality loss does not accumulate between steps. Batch mode processes several files in sequence, with per-file preview and ZIP export.
- Raw FFmpeg and offline: a free-form field gives access to the full ffmpeg command line, with live command preview and an example library. The app installs as a PWA and works offline once the ffmpeg-core binary (~31 MB) is cached.
USE CASES
- Convert or compress a video without an online converter that sends your file who knows where.
- Process confidential footage (client demos, internal recordings) without it leaving your machine.
- Produce a GIF or a short clip for a doc, a PR or a ticket.
- Caption a short video without installing anything.
- Test an ffmpeg command in the browser before putting it in a script.
The limit is the runtime itself: the WebAssembly heap caps at 2 GB, some operations (reverse, boomerang) are disabled in batch mode for that reason, and very large files remain a job for native ffmpeg.