What is pre-recording, and how to enable it?
Pre-Recording sets how long your DVR or NVR (network video recorder) will record before an event occurs. Among those events are motion, sound, video loss, and events detected in AI mode. At the same time, Post recording determines how long your recorder will record after an event occurs.
For pre-recording on your Camius Digital or Network Video Recorder, move the mouse cursor to the bottom left, click the main menu button Setup >> Record >> Record >> tick the PreRecord checkbox >> Apply.
Pre-recording default time is 5 seconds.

You can also enable prerecording on your recording while accessing it via the browser.
