POST PRODUCTION
Editing is the process of deciding what shots go where, what is left out and how to position the edited sequences so that they relate to each other.

TRADITIONAL EDITING SYSTEMS
Despite the advent of newer non-linear systems, there are still a good number of traditional editing systems being used, although this is changing rapidly.

The tape is edited electronically, unlike film where it is cut or spliced physically into place. Video editing involves copying one shot from a video cassette recorder (VCR) - the 'source' machine, onto a second VCR - the 'record' or 'edit' machine which provides the final or 'master' copy tape.

Usually a separate monitor is used for both source and record/edit machines. An editing system usually consists of three VCR machines - two sources (in case the editor wishes to mix shots onto the master) and a record machine. This setup is referred to as a three machine edit system.

Such systems have an edit controller for precise aligning of all tapes and perhaps an effects generator which permits various creative electronic effects to be employed such as fades, wipes, dissolves and mixes among other possibilities. There can be a 'character generator' which superimposes titles and basic graphics over the recorded material. Auxiliary sound systems may also be attached and mixed through an audio mixer in order to add audio effects, background noise, music or commentary. More complex systems can have sophisticated computers to provide 3-D graphics and animations for programmes.

Where resources are scarce often two VCRs will do, with one being the source and the other the record machine - called a two machine edit suite. Often there may not even be an edit controller, never mind any other form of editing equipment. This basic system is also known as 'crash editing'. However such systems may be all that is required in order for an editor to get a message across.

NON-LINEAR EDITING SYSTEMS
The increased use of computers in editing has brought about a revolution in the way post-production is achieved. Non-Linear Editing systems are now commonplace.

The use of VCRs as already described (see Traditional Editing) permits the laying down of video material one scene after another i.e. in a linear fashion. However computer software permits the manipulation of sound and pictures in much the same way as word processors handle words. Both sound and video elements can now be assembled in any order desired - referred to as non-linear editing (NLE).

There is the added advantage that access to material from the computer is instantaneous. There is no waiting period while VCRs spool back and forth to reach the desired footage. Traditional linear systems also require separate 'black boxes' or machines for every function i.e. one for each VCR, another for the audio mixer and another for the vision mixer and yet another for the character and graphics devices etc. However with the appropriate software one computer will carry out all these functions, thus eliminating the need and expense for all these other 'black boxes'.

Such systems are presently very expensive especially for outputting broadcast quality video in real time. Cheaper systems are available which allow very high quality output but apart from basic editing functions they tend not to operate in real time. They also tend to be restricted in other ways e.g. only able to render one video stream, making complex scenes impracticable, unless supplemented by an 'add-on' real time board.

However with the rapid pace of technological change such systems are catching up on their more expensive cousins e.g. Apple's Macintosh computer system and its Final Cut Pro software now enable a broadcast quality system to be purchased at a fraction of the cost of previous NLE systems. Systems are dropping in price and improving in quality by considerable margins, roughly every three months. The future looks exciting, especially for small production companies and lone operators.