Browser-based processing can be private because the file does not need to leave the device. Video Rotation Fixer reads the selected file into browser memory, runs the FFmpeg WebAssembly engine locally, and creates a download from the local result.
What stays local
The selected video is not posted to WordPress or a cloud conversion API. Network activity may still occur for normal website files, analytics or advertising where enabled, but the video bytes remain in the browser session.
Why large files are difficult
A browser may need memory for the source, processing workspace and output at the same time. A one-gigabyte input can therefore require considerably more than one gigabyte of free memory. Mobile browsers are especially likely to stop a long job.
When to use the desktop build
Use a desktop FFmpeg workflow for multi-gigabyte recordings, batch jobs, uncommon codecs, very long videos or exports that must use hardware acceleration. The browser version is best for short-to-medium clips on a reasonably modern computer.