Getting started with local video compression

LocalVideoZip is a browser tool for shrinking a video file you already have on your device. Compression is designed to run in the page (ffmpeg.wasm / WebCodecs when wired). Your file is not uploaded to our servers.

Before you start

• Prefer a desktop browser for long or 4K clips — phones often run out of memory.
• Have the source file on disk (Downloads, camera roll export, etc.).
• Know your target: messaging, email/LMS (~25 MB), a strict form (~8 MB), or a quality (CRF) preset.

Steps

1. Open the compressor.
2. Drop an MP4, WebM, or MOV onto the drop zone (or click to choose).
3. Confirm the filename and size shown in the meta line.
4. Pick a target preset.
5. Click Compress on this device. Wait for the local encode to finish (engine may still be stubbed in early builds).
6. Download the result and attach it where you need it.

How to verify nothing uploaded

Open DevTools → Network before you choose a file. After you compress, you should not see a multipart upload of your media to our origin. Static assets (CSS/JS) may load as usual; your video payload should not.

Common issues

• Unsupported format: convert or remux to MP4/WebM/MOV first on your machine.
• Tab crashes: try a shorter clip or lower resolution source on a machine with more RAM.
• Still too large: use a stricter preset or trim the clip length before compressing.

Next: messaging-friendly compression or 25 MB email/LMS caps.