News: 15.03.02

Just added a bunch more stuff to the 3rd Year projects section. More on the way as I finalise the details...

Kieran McAtamney-Sanders
Rose Bruford College
Sound & Image Design BA (Hons), year 2

Brief:

Research and present to the group a 5 minute seminar explaining the concepts behind Off-line Editing and EDL’s. Include a 1,000 word report detailing your research.

Deliverables:

• A 5 Minute Seminar
• An essay of 1,000 words

Introduction:

This report is intended to accompany my presentation detailing the concepts behind Off-line Editing and EDL’s (Edit Decision Lists). I will restrict myself to exploring the principles behind off-line editing - this report and the accompanying presentation is not intended to form a user guide to any specific package.

What Is Offline Editing?

The basic principle behind off-line editing is to allow the user to edit high quality video, via a low quality preview, which can be easily edited and manipulated without placing high demands on the user’s computer system. This allows the user to experiment with various different editing techniques without the prohibitive render times which can result from attempting to manipulate full quality video.

It should be noted, that off-line it editing is not usually used when working with DV, since this format of video is already relatively low quality/file size enough to allow direct editing of the original media. Off-line editing, however becomes far more relevant when working with higher quality video, such as film or high-definition digital video, which require high-end workstations to manipulate. It is therefore important that users of DV have at least a basic understanding of off-line editing, to allow them to adapt more easily as and when they progress to higher quality formats.

What is an EDL?

An EDL (edit decision list) is created by examining the changes made to the preview video and noting which actions are performed at specific time code points. This EDL is then used to recreate the preview edit using the original full quality video. Today, this is usually achieved using an automated process, though when working with film, it is still sometimes used to produce a printed list of edit points which are then re-created manually via traditional editing techniques (razor blade and cutting block).

Whatever mechanism, manual or automated, is used to apply the EDL to the full quality video, its effect is the same-it allows the editor the freedom to make editing decisions unhampered by restrictions imposed by rendering delays.

The Offline Editing Process:

Though there are many systems used for off-line editing, with each having its own unique techniques and idiosyncrasies, the basic process remains the same regardless of the specific packages used:

1. Create a low quality preview copy of the video, retaining accurate time code information.
   
   
2. Perform editing on the preview copy using whatever package is available/most suitable.
   
   
3. Output an EDL containing the details of the edit. This is an automated process in most packages, and the user normally has some choice of output format.
   
   
4. Pass the EDL to whatever system is being used to reconstruct the edit using the full quality video. In some cases this function will be integrated into the editing package, while in others it will be performed by a separate application. The editing decisions will then be applied to the full quality video, and the final output produced.

Offline Editing History:

Although EDL’s and off-line editing are most readily associated with the editing of video on a computer, they have their roots in somewhat simpler technologies. The concept of making editing decisions before applying them to the real media is not a new one, and was perhaps even more relevant than today when it editing was exclusively performed using the traditional cutting block methods, when editing was actually destructive to the original copy. It made good sense to plan all edits with pen and paper before taking a razor blade to your original footage!

As technology progressed, editors were able to make use of VHS and other formats to preview their edits to get some idea of the overall effect before committing themselves. With the advent of computer editing, off-line editing has taken on a whole new set of advantages and complications, though the essential ideology behind it remains the same: to allow the editor to experiment by reducing the investment of time/resources needed to see whether a particular edit works.

Bibliography:

The majority of the material in this report and the accompanying presentation is the product of my own background knowledge on the subject. However, I also referred to the following sources:

Adobe Premiere 6 help files, Adobe Premiere - release 6.01, © Adobe 2000.