Linear Video Editing
Linear video editing is the process of assembling segments of video from one or more
video sources (usually
VTPs or video tape players) to a single video source (usually a
VTR or video tape recorder). The process typically involves a computer (called an
editor) which controls the various tape machines. The computer saves the video source and
time-code information in an
EDL (
edit decision list) for later archival or in case the job is botched at some point. The EDL can then be used to reconstruct (painstakingly) the edit up to the point where the error occurred.
The problem with linear editing is that each piece of video must be laid down to the recorder in real time and once you start, you cannot go back and make a
change without
re-editing everything after the change.
Non-linear editing differs from linear editing in several fundamental ways.
First, video from the field tapes (or whatever the source is) is recorded to the editing computer's hard drive or RAID array prior to the edit session.
Next, rather than laying video to the recorder in sequential shots, the segments are assembled using a video-editing software program like Adobe Premier or Macromedia Director. The segments can be moved around at will in a drag-and-drop fashion.
Transitions (such as dissolves or wipes) can be placed between the segments. Also, most of these programs have some sort of CG or character generator feature built in for lower-thirds or titles.
The work-in-progress can be viewed at any time during the edit in real time. Once the edit is complete, it is finally laid to video.
Non-linear video editing removes the need to lay down video in real time. It also allows the individual doing the editing to make changes at any point without affecting the rest of the edit.