How the Video Rotator Works
AnyTool rotates and flips video entirely in the browser using a self-hosted single-threaded ffmpeg.wasm engine — the core (ffmpeg-core.js + the 32 MB wasm) is bundled from npm and served as a same-origin asset, so nothing is fetched from a CDN. A live CSS-transform preview shows the orientation before export. On apply, the clip is written to ffmpeg's virtual filesystem (MEMFS) and the transpose filter is used (transpose=1 for 90° clockwise, transpose=2 for 270°, two chained passes for 180°), with hflip and vflip available for mirroring. The result is re-encoded to H.264/AAC with +faststart and read back as an MP4 blob. Single-threaded is deliberate: the multi-threaded core needs SharedArrayBuffer + cross-origin isolation (COOP/COEP), which would block cross-origin ad iframes.
- Runs client-side — the video is never uploaded
- Self-hosted ffmpeg core (bundled) — no CDN
- transpose filter: 90° / 180° / 270° rotation
- hflip / vflip mirroring
- Live CSS-transform preview before export
- Re-encoded H.264/AAC MP4 (+faststart); no cap
