NLE

NLE stands for Non-Linear Editing. Non-linear editing is an offline editing format for audio, video and image editing. In offline editing, the original content is not modified during editing. In non-linear editing, the arrangements are determined and modified by special software.

In this case, the NLE performs predominantly on videos (NLVE) and audio (NLAE). Its name is in contrast to the linear video editing and movie editing methods of the 20th century. 

NLE

A marker-based playlist is used to track edits, an active edit decision list (EDL) for video and audio, or a directed acyclic graph for still images. Every time the edited audio, video, or image is created, played, or accessed, it will be recreated from the original source and the specified editing steps.

While this process is more computationally intensive than directly modifying the original content, changing edits can be almost instantaneous, avoiding further generational loss when editing audio, video or image.

Basic Techniques

A non-linear editing approach can be used when all assets are available as files on video servers or local solid state drives or hard disks rather than recordings on reels or tapes.

Whereas linear editing depends on the need to view the movie sequentially or listen to the tape, non-linear editing provides direct access to any video frame in a digital video clip, as it stands, without having to play or scroll/shuttle adjacent images.

For more information about video editing and editing programmes;

https://cinema8.com/blog/top-15-video-editing-software