Linear editing? What's that? In recent years, most new video editing equipment installations have consisted of non-linear editing tools. Non-linear editors came into being when mass produced computer technology became powerful enough to store, record and play video of reasonably good quality. Until then, video was stored only on tape. It was termed "linear" because to find a particular scene, the tape would have to be played, or at least fast-forwarded, from wherever it was parked, to wherever the scene was recorded. And when you were editing, which was the process of copying selected material from source tapes to an edited master tape, if you wanted to add change, lengthen or shorten a piece at the beginning of the edited master, you would have to re-record everything that followed your change.

The term "non-linear" became widely used because video media is stored on disk, and to locate and view a particular scene is immediate - all you need is some kind of directory that tells you where on the disk it is stored, and you can access it with the click of a mouse button. Also, with a non-linear system, you can work on an edited master from any direction - you can first place shots at the end, then do the beginning and come back later and finish the middle. Wherever you place a new shot, or make any other kind of change, it is done as fast as you enter the command, because computer disks can play out material in any sequence; it doesn't matter where on the disk it is physically located.

Not only do you get the speed of direct access to any clip and the flexibility to make changes anywhere in the master with non-linear editing, you also get a very powerful user interface, with high resolution graphic displays showing a representation of your show on your computer screen. You can look at the timeline on a scale that fits your whole show on the screen, or you can expand the timeline to show all the detail of only a few seconds filling your screen. You can point with a mouse and quickly pull the end of a scene, making it longer or shorter.

It is true that for many video editing tasks, non-linear equipment is ideal. But in spite of the general trend toward non-linear, there are still many linear editing systems in use in our industry. Not only are they still in use, but they continue to be upgraded with new equipment and more linear editing rooms are being built all the time. It turns out that for many editing applications, linear systems have compelling advantages.

Let's look at the capabilities of a linear system that are usually missing from non-linear systems.

1. Simultaneous control of multiple sources: This includes VTRs, ATRs, Disk-based media, and effects channels. The model for non-linear is hard to stretch to cover more than one or two things happening at once.

2. Real-time, highest-quality multiple channel video switcher and digital effects. Does anyone watch "Entertainment Tonight" or "Access Hollywood?" Those are examples of shows that are edited with linear equipment, and probably always will be. There are 7, 8 or 9 separate video sources rolling during some shots - this requires the resources of a powerful digital switcher, a critical component of a linear edit bay. When you see the fancy effects with moving pictures being wrapped around a solid shape, or being flown around the screen, those are generated in real time on a linear system. If they can be generated at all on a non-linear system, it may take minutes or hours to render a few seconds of effects.

3. The ability to use source footage for editing immediately, without need to digitize, whether from a tape or camera or feed. There are many applications that have just minutes to finish the show before going to air. Last-minute shots have to be incorporated quickly, and there just isn't the time to go through the preliminary steps to do the job in a non-linear way. In the non-linear world, all the source material has to be copied onto a dedicated computer. 20 hours of raw footage equals 20 hours of copying (at least).

Up until now, the choice has been black or white: linear or non-linear. Except for a few attempts to extend the capabilities of a linear system to add some disk handling or the addition of a few real time effects to a nonlinear system, there has not been an editing system available that includes all the best features of both linear and nonlinear editing systems.

At Editware, we have been hearing for years that what the industry needs is a true hybrid system - a system that really offers the best of both. If only a non-linear system could incorporate a dedicated video switcher! This has been difficult to do because of the nature of non-linear systems. Virtually all non-linear systems require that the media, the raw footage that goes into the editing process, must reside in the disk storage, dedicated for that purpose. This means that external, real time video processing equipment, like video switchers and digital effects cannot be used. Any actual video processing is done completely inside the non-linear system. It can do some effects, but generally these are limited to one or two video channels, and usually need to be rendered, a process which can take much longer than real time. There is just no substitute for a video switcher; no computer has the power to provide real-time multiple channel, multiple-effects video processing.

To respond to this need, Editware offers two hybrid editing controllers that make full use of the power of disk-based video. Our systems are based on shared video server technology. Video servers are networked, multi-channel storage devices incorporating multiple hard disk drives, some of the fastest, highest-capacity disk drives available - servers have capacity measured in hundreds of Gigabytes or even Terabytes. They provide the storage for many hours of video, and allow multiple users to have access to the same material simultaneously - for multiple purposes. That means, for example, that as media is being recorded on one or more channels, the same material can be accessed by other channels to build an finished program, at the same time, other channels can be used to edit a promo or trailer piece, and yet another staffer may have access to log descriptions of the material for an archival system, and as any of these jobs, or even a piece of a job, are completed, another application can play it out, to be recorded to tape, or to feed the transmitter or a satellite uplink. All this can be done without ever copying the underlying media source files.

Editware's DPE-500 series editing controller with the NLE option, provides all of the advantages of linear editing, along with non-linear speed, when used with the Grass Valley Group Profile® video server. The DPE uses a traditional linear user interface with extensions that support its non-linear functions. Any experienced linear editor will be comfortable with the user interface.

Also, brand-new at NAB 2001, the Editware Fastrack VS, is designed for use with a choice of video servers, including GVG Profile, Sony MAV and Accom servers. It provides much of the power of a linear editing systems, along with the key elements of a non-linear system:

1. Immediate access to any frame of any source clip.
2. Ability to insert or delete or change material at any point of an edited master.
3. An intuitive, convenient graphical user interface.

It does this through the use of video servers for direct access to source material and for non-linear editing. And it does this with a graphical user interface that works equally well in the linear and non-linear realms.

By adding video servers to post-production, the result is much more than the sum of the parts. Not satisfied with the compromises of either a fully linear or fully non-linear editing system? Consider a hybrid solution.

 

Jay Coley is one of the founders and is CEO of Editware. Before Editware, Jay was Product Manager for editors at the Grass Valley Group. He holds a BS in Engineering from UCLA. Editware was started in 1996.