Non-linear editing

Non-destructive editing is a form of audio, video or image editing where the original content is not modified in the course of editing – instead the edits themselves are specified and modified by specialized software. A pointer-based playlist – effectively an edit decision list (EDL) – for video or a directed acyclic graph for still images is used to keep track of edits. Each time the edited audio, video, or image is rendered, played back, or accessed, it is reconstructed from the original source and the specified editing steps. Although this process is more computationally intensive than directly modifying the original content, changing the edits themselves can be almost instantaneous, and it prevents further generation loss as the audio, video, or image is edited.

A non-linear editing system (NLE) is a video (NLVE) or audio editing (NLAE) digital audio workstation (DAW) system that performs non-destructive editing on source material. The name is in contrast to 20th century methods of linear video editing and film editing.

Non-linear editing is the most natural approach when all assets are available as files on video servers or hard disks, rather than recordings on reels or tapes—while linear editing is tied to the need to sequentially view film or hear tape.

When ingesting audio or video feeds, metadata are attached to the clip. Those metadata can be attached automatically (timecode, localization, take number, name of the clip) or manually (players names, characters, in sports: red card, goal...).

Non-linear editing enables direct access to any video frame in a digital video clip, without needing to play or scrub/shuttle through adjacent footage to reach it, as is necessary with video tape linear editing systems. It is now possible to access any frame by entering directly the timecode or the descriptive metadata. An editor can, for example at the end of the day in the Olympic Games, easily retrieve all the clips related to the players who received a gold medal.

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