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A SCENARIA FOR VIDEO



                                               A SCENARIA FOR VIDEO

                                                             by

                                                    DEAN WINKLER
                                             President, Post Perfect NY


It's that time of year again, and I've just completed my annual spring
ritual: off to Las Vegas to attend NAB, a stop in Utah afterwards for a
few precious turns on my monoski, and back to New York. While Vegas is
always somewhat surreal, NAB was particularly odd this year; a type of
collective insanity seemed to overrun the convention. If you will permit
me a little humorous exaggeration, numerous manufacturers were claiming
that "in six months they will have full resolution component digital
video, real time compositing and a Jumbotron running on an Apple
Newton." What I found bizarre was that so many people believed it.

What was driving this? The revolution in off line editing made
practical by Avid and other manufacturers of computer/disk based
nonlinear off line systems does not yet have an equivalent for online
editing. That so many attendees were salivating over "vaporware" 
demonstrates just how strong the demand for this is. 
Over the past fifteen years the changes in online editing systems 
have been evolutionary, not revolutionary. Although the signal quality 
of online editing systems has improved dramatically and
the image and sound quality of a component digital online system is
truly astonishing, the basic configuration of these systems has remained
the same. Online editing systems are still assembled from individual,
hardware based machines. Typically, this includes a video switcher, a
few channels of digital video effects devices, an audio mixer, a
character generator, an editing control computer, a signal router, 
and several video tape recorders and digital disk recorders. 
There are several disadvantages to building an editing system this way: 
The system does not have true random access capability. 
Each machine runs under it's own individual "operatingsystem", 
with the edit control computer functioning as little more than
a master synchronizer (as opposed to having one integrated control
structure for all of the system's functions). There is a high degree of 
operational complexity and the system is expensive to purchase and
maintain.

Given these disadvantages, why build an online editing system this way?
Beyond maximizing signal quality, a conventional online editing system
has one capability that outweighs all of the disadvantages listed above:
the ability to perform real time previews. By this I mean that the
system can playback several full resolution sources simultaneously, 
and while these sources are rolling, multiple parameters can be adjusted
with the results viewed in real time. For example, repositioning, edge
softness, transparency and color saturation of an image can all be
adjusted in real time, while viewing the relationship between that image
and other images in a scene. This real time preview capability is 
particularly essential when compositing images for visual effects
sequences. 

Clearly, it would be wonderful to have a new type of online editing
system that combined the signal quality and real time preview capability
of existing systems, with true random access and a totally integrated
control architecture. Ideally, such a system should also be simpler to
operate and less expensive to build and maintain than current online
editing systems.

Unfortunately, none of the computer/disk based systems currently being
touted by manufacturers as replacements for the existing online editing
systems will be able to meet these criteria. Even if, for the sake of
argument, these computer/disk based systems could offer signal quality
equal to the quality of existing component digital online editing
systems (a big assumption, particularly with regard to digital video
effects), and these systems were capable of performing all of their
"rendering" operations in real time, they still would not be able to
offer a sufficient level of real time preview capability. 
There are three reasons for this:

First, the bandwidth required to simultaneously play back several
sources of uncompressed, real time component digital video and audio is
too large for any single computer/disk system that currently exists.
Second, the computing power required to execute all of the real time
functions of an on line editing system in software is far beyond the
capabilities of even the fastest existing supercomputer. 
And third, pull down menus or similar CRT based controls will never 
be ergonomically fast enough. Some type of physical controls 
(e.g., switches, shaft encoders, lever arms,  etc.) will continue to be
required. 

"Ah," I imagine you're saying, "if this is true, why has the film
community thoroughly embraced computer/disk based systems for
compositing visual effects sequences for movies?". Bear in mind that 
their point of comparison is not online video editing systems, 
as these systems are not capable of working with the high resolution 
images required for motion picture scenes. The film community has 
adopted computer/disk based systems as an alternative to optical
printers. By comparison to optical printers, computer/disk based systems
are a godsend. If, however, a high resolution equivalent of current
online video editing systems was readily available, I'm willing to bet
that California would be littered with them. Lest you think I'm merely
whining about the direction I see the manufacturers in our industry
heading in, allow me to propose a solution.

An excellent model for a new type of online video editing system
already exists in the audio world: The "Scenaria", manufactured by 
Solid State Logic (SSL). We have three of these remarkable machines at 
Mixed Nuts (Post Perfect's audio division), and I have spent a
considerable amount of time using them. The Scenaria is a complete, 
"on line" post production system for audio. It integrates all of the
functions traditionally executed by individual pieces of hardware in
audio postproduction environment. For the purpose of it as a model 
for a new online video editing system, the following capabilities of 
Scenaria should be emulated:

1. The signal quality of the system is excellent. 

2. It is a true random access system, with multiple disks that can be
assigned to different projects. 

3. It provides complete real time preview capabilities: Up to 32
channels of full resolution digital audio and one channel of reference
quality video can be played and modified simultaneously. The results of
adjusting any of the signal parameters (e.g., channel levels,
equalization, dynamics, etc.) can be heard in real time, 
as the controls are adjusted.

4. It uses a combination of CRT based menus and assignable, physical
controls. All of the functions of the machine are accessible from the
CRT menus, and in addition, functions which need to be adjusted in real
time can be assigned to physical shaft encoders, switches and faders. 

5. It is a completely integrated system, with one master "timeline". 
All of the functions of the machine are controlled from this one
timeline and are fully automated. 

6. Signal routing between the Scenaria and the external world is fully
integrated into the control architecture. Even its patchbays are under
system control. SSL accomplished this by building a "hybrid" system.
They used standard computer components (e.g., microprocessors, disk
drives, etc.) augmented with dedicated hardware to execute specific
functions (e.g., signal routing, A/D D/A converters, etc.). The software
they developed integrated all of these separate components together into
a unified system, so that the Scenaria operates as if it were one
machine. This same approach could be used to develop a revolutionary on
line video editing system. I believe that such a system should sell for
$650,000 or less, including everything except the video tape recorders.
In the hope of getting this developed, Post Perfect is offering the
following: 

First, I will personally give an extended Scenaria demonstration to any
interested video manufacturer (engineers from Avid have already taken me
up on this). Second, hanging on the wall of my office, directly below
one of my ceramic "Elvis" plates, is Post Perfect purchase order number
18042, for an on line video editing system that meets all of the above
specifications. Hopefully, there is a manufacturer willing to take it
off of my wall.