How AetherCut Edits Video Entirely in Your Browser — Zero Server Uploads

Most video editors upload your footage the moment you start. Your raw clips move to a server you don't control, processed by infrastructure you can't audit. AetherCut works differently — and you can verify it yourself in under 60 seconds.
Here's the full technical breakdown.

The Architecture: Why Nothing Leaves Your Device
AetherCut runs inside a browser tab. No install. No account required to start. Every processing operation — cutting, captioning, chroma key, export — executes locally using three browser APIs that have quietly made client-side video processing viable.
HTML5 Canvas API
The Canvas API is the rendering layer. Every frame you see in the AetherCut timeline is drawn to an off-screen canvas. Compositing, overlays, text, and visual effects are applied directly in-memory on your device. No frame data is serialized and sent over the wire.
WebCodecs API — H.264 Hardware-Accelerated Export
The WebCodecs API is what makes 5x realtime export possible. It gives JavaScript direct access to the browser's hardware video encoder — the same H.264 acceleration your GPU uses for everything else.
Before WebCodecs, browser-based video export had to go through software encoders, which were slow and CPU-heavy. WebCodecs bypasses that entirely.
The practical result: a 60-second 1080p clip exports in roughly 10–12 seconds on a mid-range machine. The encoded output never touches a server — it writes directly to your local filesystem.