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The Complete Series

Technical Report: New Developments in Nonlinear Video

A three-part series on how the latest PC developments are making it possible to put video editing systems together from off-the-shelf components.

Putting High-Performance Nonlinear Systems on Personal Computers

Networking and Video Servers

System Design Issues (This article)


Technical Report
New Developments in Nonlinear Editing, Part 3
Design Issues

By Robert Lamm, CYNC Corp.

In the past, selecting a nonlinear editing system was just a question of evaluating just a few parameters. Turnkey, black-box systems were primarily bought on the basis of image quality with some simple functional criteria (like EDL support and batch digitizing) thrown in.

Now that most nonlinear systems exceed the data rate requirements needed for transparency and have more functionality than any A/B roll suite ever had, choosing a system has gotten a little more complicated:

First of all, nonlinear systems don't just edit video any more: They're compositing machines which take a variety of media: animations, stills, video, etc. and layer/edit them with considerable sophistication. And the output isn't just to videotape: Users also want interactive CD-ROMs, video and stills for web pages and even hard-copy paper output made from the same media. Finally, these systems are no longer isolated digital islands of production technology in an analog sea: They're multimedia computers which need to interface with existing applications, networks, and workflows.

Editing systems also don't come in a single box anymore. Like the radio that grew up into a stereo, nonlinear software and hardware components are mixed and matched from a dizzying array of possibilities...

Common Questions

First and foremost should be: What do you want to do?

Some users want to edit video, plain and simple. For this, the ability to play back edits immediately so that timing can be checked is critical. For those who want to load lots of footage onto the machine and make decisions during the editing process, the ability to batch digitize is important: They can load lots of low-data-rate video into the computer during the weeding-out stage, then batch digitize the stuff they need for the final edit in at a higher quality.

Another issue for video editors is what signal types the system supports. Just about all systems can handle composite and Y/C, many of them can handle component betacam. But few can handle serial digital video and none can currently input/output the new DV format in native form, although that's likely to change soon. Some users may want to be able to edit in PAL, the European TV standard.

A lot of nonlinear users want to do extensive amounts of special effects. Here, the ability to see them in real time makes the creative process a lot faster. But special hardware is required and the software has to be able to use it.

Many nonlinear system users are incorporating large amounts of animation, this introduces a number of issues. If the animations are of a technical nature, such as 3D models of machinery or buildings, a great deal of time can be saved if the animation package can use the CAD files that are often used to design these objects to create the 3D animated models. Only a limited number of packages can do this, this in turn affects nonlinear editing package selection, since it's important that the animation and nonlinear hardware be maximally compatible.

Long, complex video edits need the ability to database clips and sequences. That way, one can sort and flag clips according to various criteria as well as arrange them into storyboards. Some applications allow you to save completed sequences as clips, which you can then cut-and-paste into larger units while still retaining the ability to modify them. Database management functions which allow you to move media around (for example, to put stock footage into special folders) and to automatically delete all footage that isn't in use is very handy and goes a long way towards preventing crippling user mistakes.

Multimedia

CD-ROM and Web-site creation has a wholly different set of requirements: Image quality is much less important, the ability to export the appropriate file format is crucial. This is not just an issue of having both Video-for-Windows (.AVI) and QuickTime (.MOV), but of having the appropriate compression algorithms and the ability to set things like data rates and sector padding so they play smoothly on whatever hardware they're supposed to work on. Otherwise, you may have to go through lots of file-format acrobatics to get what you need, this can be very time and disk-space consuming.

Few nonlinear editing systems can export MPEG files. Although viewers need special MPEG playback hardware in their computers, it's currently the only way to get VHS-quality video playback off a CD-ROM. Some nonlinear applications (like Avid MCXpress for NT) have MPEG exporting built into them, others can interface with separate software encoders. But software MPEG compression is very time-consuming, a lot of users get specialized hardware that can do it in real-time...

All these multimedia files have a problem with long blanking times: There is no CRT frame to hide the black edge around the image. Nonlinear editing packages used for multimedia production need to be able to trim this off...

Reliability is a big issue with all CD-ROM's. A large proportion of them are returned, the main reason is that they don't work in the particular customer's computer. It pays to develop CD's on the same platform as it will be played on- it's easier to debug when you can constantly try it out.

A lot of nonlinear users want hard-copy paper stills of some of the material, either for packaging, user-guides, or publicity. This requires much greater image quality than is normally used for video, and the different proportions of the printed page create layout problems for artists who want to reuse video-oriented graphics on printed matter. In these situations, nonlinear systems not only need to be able to handle desktop-publishing file formats, as much of the artwork as possible needs to be made with high-quality bitmaps or vector-based object-oriented elements that can be easily rearranged for different proprortions and resized for the varying resolutions of video and print. For full-page stills, it may be neccessary to scan photographic film images into the system with a high-resolution scanner. Hi-res output is also an issue, the files are usually way too big to fit on a floppy and may need to be carried to the imaging station on special media, such as a Zip or Jaz drive.

Film

Many people are surprised to learn that the video-image-quality of film-editing nonlinear editors can be pretty poor. The reason is that the film negative will be used to make the prints and the video display is merely for editing purposes. Film runs at 24 frames/second as opposed to 30 frames/second for video, so special provision has to be made to accomodate this. In addition, film uses edge numbers rather than SMPTE timecode to keep track of frames, the editing application needs to be able to calculate these from the SMPTE timecode on the video transfer. Other neccessary features are the ability to generate a list of all footage that is used more than once (so that an internegative can be made) as well as all optical effects. A separate SMPTE timecode edit list is usually required for the audio cut.

Work Environments

Commercial Users (in other words, people who do work for hire) need to have fast turn-around: Once the edit is done, the client needs to be able to walk out with his production and the system has to be ready to accept the next user. The editor is likely to be working on it full-time and will appreciate any functionality that gives him more control or quicker execution, even if it takes longer to explore and learn all of it. In addition, the type of material he is likely to be editing is different: Multicamera dramatic shows which benefit from multicamera playback options, indexing to scripts, etc.

Rendering times, especially for common effects like effects like dissolves and keys, are anathema to the quick-in, quick-out goal and commercial facilities generally want everything as real-time as possible. This is possible with special hardware like the Truevision Targa 2000RTX board, Pinnacle Alladin, etc.

Commercial facilities are likely to set up a simple system for 'offline' rough cutting (sometimes even on-location with a portable computer) and do the final high-quality 'online' edit on a fancier system. For this they need the ability to export EDL's and batch digitize. They also want the ability to generate graphics and text from a customer's word-processing application: That way the client can bring his credits in on a floppy and the production house isn't liable for typos. Having all this on the machine in object-oriented form allows for corrections at any stage should they still be neccessary.

Larger facilities may have lots of individual workstations dedicated to tasks like logging, off-line editing, graphics/animation, on-line final cutting, and even video servers for print-to-tape and broadcast. Providing all these machines with enough storage to satisfy their needs can get expensive and doesn't solve the problem of transferring work from one station to another as productions progress. The solution is to network the systems together and pool all the storage in a single, shared location. But these systems need to be carefully configured because the data-rate requirements of video are very high and can easily bring the network down if poor design causes the streams to overlap too much. The ideal facility is as carefully laid out as a car assembly-line, with special consideration given to the workflow habits of the personnel.

Reliablility is particularly important at commercial facilities. Customers are likely to be intolerant of any crashes, especially if work is lost. At minimum, a makegood on the bill will be required. Commonly, the facility will also have to scramble to reschedule everyone around the unlucky production and have to eat lots of overtime. Continued unreliability will quickly make any system unrentable.

Industrial users have a different set of requirements: They're unlikely to be spending all their time with the nonlinear editing application and prefer an easy-to-use, intuitive interface to an unfamiliar, complicated one that they'll never fully explore. Their systems need to integrate with the company's existing networks and applications so that the video producer can exchange files with others and access corporate databases. Being able to run the same design and database applications that the company uses will allow him to use this material to generate his own text and graphics rather than having to always ask other people in the company to make them up for him and sneakernet them into his system on floppies...

Independents and hobbyists are usually on very tight budgets, they're usually willing to forego speed (and to a degree, quality) in return for economy. But they need all the whiz-bang functionality they can get: They usually don't have any other post-production tools other than the one system, so it needs to be able to do everything they need, even if it takes a while or is a bit clumsy to set up. These systems also need to be maximally compatible with off-the-shelf software: Users are very likely to add audio-editing, paint and animation applications to their system and they all need to run with each other. A larger facility can accomodate incompatible applications by running them on separate stations, this isn't an option with one-computer operation.

Platform

One common question I get is which platform I think is best. Until recently, most nonlinear packages only ran on the Mac, so there really wasn't much choice. Now, even heavily Mac-oriented companies like Avid have ported their software to other operating systems, most commonly NT, and the consensus seems to be that this is the OS of the future. I would agree with that, but I don't expect the Mac to die anytime soon and anyone buying one is still likely to get plenty of use out of it. I would generally advise users to continue with whatever platform they currently have in-house: It simplifies compatibility issues.

Proprietary vs. Open-System

I'm a big fan of open-system solutions. One can usually cobble up a system that more precisely matches the user's requirements and also costs less than any proprietary black-box. Upgrade options are usually broader too, since one has a broad variety of off-the-shelf applications to choose from, rather than the more limited functionality that a single company can come up with. But open systems take more work to assemble and debug- you're not getting the whole thing all prepacked from the manufacturer in a box. Well, that's what the integrator is for...

Representative Systems

(This list is not meant to be exhaustive, merely illustrative of what is currently available at various levels of performance.)

For the Hobbyist
Adobe Premiere

I'll say it right here: Premiere can do more than any other nonlinear program out there: More video tracks, audio tracks, effects, filters, etc. than anyone else. It's also the only fully open-system application on the market: It runs on any hardware that supports Video-for-Windows or Quicktime. But everything, absolutely everything is done in software, including playback of Video-for-Windows and QuickTime files, and this makes for some big inconveniences. Most serious is the need to render out a file of the complete program before smooth playback can take place on most hardware. This can take hours, even days, for a half-hour program! The only capture/playback card that doesn't suffer from this limitation is the Interactive Images Plum card, which I strongly recommend for anyone who wants to edit video with Premiere. A complete system (including computer) can be assembled for $7000 and up and it'll do a lot. The main limitation is that the system can only handle composite and Y/C video and is limited to data rates of about 180KB/frame.

But if you're doing multimedia production, Premiere really shines and the rendering requirement isn't as onerous: All multimedia files need to be rendered anyway and Premiere can export more file types and gives you more control over their settings than most other applications. The only filetype it can't export is MPEG. Many people with more expensive systems have a copy of Premiere on their system to handle multimedia stuff, it's that useful. And Premiere comes in both Mac and PC versions...

For the Corporate/On-Line Producer
Avid MCXpress

This little-known program is perfect for the mid-range video editor who wants high image quality and a quick, efficient interface. The NT version actually has the highest data rate capability of ALL Avid products (over 330KB/frame), and it runs on a variety of capture hardware. When used with the Truevision Targa 2000RTX, some two-channel effects like dissolves, picture-in-picture and keys can take place in real time. This is a real boon because these are the effects that typically take longest to render: dissolves because they're so common, keys and picture-in-picture because the durations tend to be longer than a second or two. MCXpress has pretty decent databasing capablities including keyword search, sequence storage, storyboarding, and unused-footage elimination. The object-based character-generator (Inscriber) is something of a standard in the industry: A very object oriented package with the ability to precisely position titles over video, etc.. The NT version of MCXpress runs on a variety of boards and even comes with an MPEG encoder. Complete systems cost from $15,000 on up.

For Real-Time Special Effects
Scitex Videosphere

Scitex makes unique nonlinear systems that have a substantial amount of special real-time effects hardware. They can do a variety of DVE, chromakey, colorcorrection and other effects in realtime with a very interactive, realtime interface that makes adjustment easy and intuitive. Midrange systems run in the $40-45,000 range.

For top-of-the-line post facilities
Avid Media Composer 8000

This is Avid's top-of-the-line machine and has all sorts of bells and whistles. Among them: full range of film, video and audio-editing tools, a real-time multicamera play option that's handy for editing TV shows, lots of interactivity, audio EQ, lots of realtime effects and more. But it's expensive, about $150,000 for a system.

Film

People are often surprised to find out that film-based nonlinear editing systems are not only cheap, they hold LOTS of media! Tha’t mainly because the image quality isn’t very important and the image can be highly compressed. There are three main systems in use, the Lightworks and Avid high-end applications, and the D-Vision PRO, which generates not only film/audio cut lists, but also video EDL’s that I have personally tested and found to be rock-solid reliable. It starts at the amazingly low price of $7000!

Other add-ons:

Today's open-system designs allow for lots of extra tools on nonlinear systems, many of which you are likely to have heard of or be familiar with:

Graphics programs:

Adobe Photoshop: Photoshop is a general-purpose paint/processing program. It's not only useful for generating graphics, it's also indispensable for color-correction of stills. There are very few prints and slides that can't do with a little improvement in PhotoShop, not only to remove dust and scratches, but also to make the colors more vibrant, reduce contrast (video can’t reproduce photo contrasts) and compensate for color differences between images.

Coreldraw: This is a vector-based drawing package. Unlike PhotoShop 'bitmap' images, which are stored as pixels and have built-in resolution, Coreldraw 'vector-based' images are stored as shape algorithms and can be enlarged indefinitely without any loss of detail or smoothness. The individual elements can be rearranged and resized as desired without any loss of quality. This makes Coreldraw ideal for graphics that will exist in multiple versions or be repurposed in print.

Coreldraw also comes with a large library of clip-art (such as models of people, animals, symbols, etc.) and an automatic chart-making function that you only need to type data into and it will automatically draw pies, bars and graphs to the appropriate dimensions.

QFX: This is a video-oriented package with the paint and image-processing capability of PhotoShop and the drawing capability of CorelDraw. But the main attraction is the queing, which allows you to have the program memorize a series of steps and then perform them over and over again. A typical application would be to take a few hundred PhotoCD images with black edges on them (a common occurence) and to automatically crop them and save the images on the computer drive. Just the savings in labor alone on a job like that is enough to pay for the program many times over...

Animation:

Animator PRO and Studio: These programs produce Bugs-Bunny-type of 2-D animations. Animator PRO is the DOS version, and has a limit of 256 colors. Animator Studio is the Windows version, can handle sound, but is a little slower. Although these programs are very simple, a surprising amount of work is being generated on them, for example, Dr. Katz, Professional Therapist, which runs on Comedy Central and is made here in Boston by Tom Snyder Productions, is made with Animator PRO and edited on Avid MCXpresses.

3D Max: This and its DOS version, 3D-Studio is the standard in 3D animation. (More people use this application than Alias, Wavefront and SoftImage combined). It's strength is the sophisticated modeling tools that allow you to make complicated shapes quickly and easily. It can also be used to animate humanoid forms as well as import designs from CAD packages like AutoCAD. It’s a complicated package, though, and takes a while to learn.

Interactive:

There are really two options on CD distribution: To make an interactive program or to use HTML and allow people to browse the CD with Netscape or similar browser. Many wordprocessors allow you to generate HTML scripts, to generate more sophisticated presentations, one needs a program like MacroMedia Director. This not only allows you to position and animate a variety of objects, one can also make all of them sensitive to mouse clicks that can send the user to another part of the CD. Interactive presentations are often the best way to present reference material or lots of information that not everyone will want (or be able to) sit through at any one time. Users can click their way through the topics that interest them and leave the rest for later.

For more information:

The Boston Film/Video Foundation offers classes in a lot of these systems. They can be reached at (617) 536-1540, bfvf@aol.com.

Bob Lamm is Manager at CYNC Corp.,a video dealership that designs, integrates and sells (among other things) nonlinear editing systems. He can be reached at (617) 277-4317, lamm@cync.com.. CYNC's website (Which has pricing info, etc.) is www.cync.com.

Posted: February 1997
Bob Lamm, SMPTE/New England Newsletter/Web Page Editor
blamm@cync.com