Desktop Video: The DTV Edit Controller
Every beginning editor dreams of a totally automatic system that assembles every shot of a video--without the help of human hands. Today's PC-based edit controllers can do this, and for prices that start at less than $200.
In this month's column, we'll survey DTV computers as edit controllers. Some of the least expensive DTV products are edit controllers, notably Abbate Video Toolkit and Gold Disk Video Director. They perform analog linear tape-based editing, as opposed to digital nonlinear disk-based editing.
Digital nonlinear enthusiasts will tell you, "Tape is dead!" Don't believe them. Videotape is cheaper; 10 cents a minute compared to $100 for disk storage of one minute of high-quality digital video. Videotape is higher quality; going straight from tape to tape keeps you free of artifacts from digital video compression. And camcorder videotape itself may soon become digital, with the new DVC (digital video cassette) coming next year. So there will probably be a videotape edit controller in your future.
Here's how to use the DTV kind.
What It Does
When you use the DTV computer as an edit controller, it directs the videotape machines, making the source deck play and the recorder record. The source deck searches for an exact frame 150 frames before the edit in-point, pauses and then "prerolls."
This gives the deck the five seconds needed for the video signal to stabilize. When the source deck reaches the edit in-point, the DTV edit controller puts the record deck into record mode. Low-cost edit controllers simply release the record deck from "record pause" mode a few frames before the source deck reaches the in-point. Pro decks also preroll the record deck.
The video signals themselves, composite or S-video, bypass the DTV edit controller and go from the source deck to the record deck; they might pass through an external switcher like a Panasonic WJ-AVE7 or Videonics MX-1 on the way. You only connect the control signals--Sony's LANC or Control-L, Panasonic's five-pin Control-M, RS-232, or nine-pin serial RS-422--to the computer. Your video remains an analog signal. It is not digitized. Only control signals and time code go through the computer.
Some DTV computers are more than just DTV edit controllers; they pass the video through the computer for titling and graphics overlays, for switching and special effects, or for digital storage and hard disk. (We'll address those in future columns.)
Computer vs. Stand-alone
There are four basic reasons why a DTV computer is a much better edit controller than dedicated hardware or "stand-alone" edit controllers: 1) the graphics screen; 2) the mouse; 3) the enormous computer memory; and 4) the computer's database functionality. (For more on stand-alone edit controllers, see the SEG and TBC Buyer's Guides in the July 1994 Videomaker.)
Onscreen graphics simulate expensive physical elements like buttons for play, rewind, fast forward and so on. Numeric displays for time codes (hours:minutes:seconds:frames) can be made any size and color, unlike small monochrome LED or LCD displays. Some pricey software packages mimic the arrangement of front-panel controls of well-known controllers; this helps editors adjust to computer equipment more easily. Unlike mechanical buttons, which will wear out, soil and eventually fail, on-screen buttons stay shiny and functional.
The mouse can model the actions of a complicated jog/shuttle wheel for transporting the tapes as you select and log your shots. Jog (single-frame forward and reverse) and shuttle (variable speed forward and reverse) are standard on high-end pro edit decks. You can click and drag the mouse to the right or left, signaling the computer to change the speed of even consumer-level recorders. A mouse costs a fraction of what a jog/shuttle wheel would set you back, given its complex switches and optical angle encoders.
The computer memory can store a nearly unlimited number of edit in- and out- points of your edit decision list (EDL). Dedicated stand-alone controllers, like Sony's RM-E700 for example, usually stop at 99 edits. Since you can save the list on a floppy or hard disk, you can start a second list while the computer saves the first. This means you can manage many editing projects at the same time.
Finally, computers are great for databases. Say good-bye to your loose sheets of paper, notebooks and high-tech index cards. With a DTV computer, you can type in comments for each scene, setup and shot (or take or clip). With a mouse click, you can search and sort your shots in a number of ways.
For example: you can arrange them in scene and shot order, while also requiring the word "good" or "best take" to appear in the comments field. You can enter any key words in these comment areas, even dialogue. Some editors like to classify shots as indoor or outdoor, or as close-up, medium shot, long shot and so on. The database fields can capture this info for you, and later reorganize your material with a few keystrokes.
How do you choose a DTV computer and edit controller? There are software and hardware combos for all the platforms: Amiga, Macintosh and PC. (See the March 1994 issue of Videomaker and check the DTV Buyer's Guide table of video editors for a list of products, company names and phone numbers.)
Let's look at the performance you can expect from products costing $200 or $300. While we're at it, we'll consider some of the added features you'll find in edit controllers costing $1000 to $2000.
Low-cost products like Abbate's Video Toolkit and Gold Disk Video Director are "cuts-only" editors. They include software and a simple set of cables to control a single source deck and the recorder. They exercise a minimal degree of control over the recorder compared to more professional systems; they can still achieve near-frame accurate editing.
Most consumer recorders have no time code. (The new Sony EV-S7000 Hi8 is an exception.) Consequently, these low-end editors don't expect any time code to come from the recorder. They use one-way Control-S type protocols on the record side, rather than two-way Control-L. Some even use an infrared remote control signal that simply pauses and unpauses the recorder.
It may be hard to appreciate the importance of time code for your source decks. Suppose your edit controller memorized the in- and out-points for a number of shots from the "counter" numbers of a deck counting control-track pulses, one for each frame. Now suppose you take that tape out of the source deck and put it back in. The counter resets to zero automatically. The only way you can reestablish the relationship between edit-point numbers and video frames is to rewind the tape, set the counter back to zero and then proceed. You must do this for each and every tape you put in. If you didn't properly zero the counter when you initially marked your edit points, you have a problem.
With time code, every frame of your tape has a unique address number recorded right on the videotape. When you insert the tape--even somewhere in the middle--those unique numbers appear. Your edit lists are ready to go to work immediately.
Insert Mode and Time Code
More sophisticated editing packages from Interactive Microsystems, Future Video and RGB Computer products can take full advantage of time code, even in decks not technically equipped for it. Future Video and others make a time-code generator-reader that puts SMPTE time code on an audio track of a deck. Now the edit recorder operates in "insert" mode instead of the simpler "assemble" mode. The edit controller moves the recorder to a specific frame and records over or inserts new video or audio material over the old, separately if the deck supports independent audio/video dubbing.
Most low-cost packages are event list editors or EDL editors, rather than timeline-based editors. In EDL editing, every scene gets one line in the vertically arranged edit decision list, regardless of its length.
The latest trend: using the graphics capability of the computer screen to represent a video clip by a rectangle whose length is proportional to the duration of the clip. These clips fall along a horizontal "timeline" that lets you visualize the pacing of the video. Short shots appear short; longer are clearly longer.
A variation on event list editing is "storyboard" editing. The presentation is horizontal, but every clip is now represented by a picture icon and label. Gold Disk has redesigned Video Director's 2.0 interface to this storyboard look. (See the April 1994 Desktop Video column "Computer-based Editing" for more on true timeline-based editing.)
One enhancement on the low-cost editors: capturing a frame of video at the start of each clip, to provide a picture icon. Remember, this requires you to invest in a video capture card like the Supermac Video Spigot or Intel Smart Video Recorder, which could cost more than the edit controller itself.
A/B Roll Controllers
More sophisticated and expensive edit controllers--ETC Ensemble Pro, RGB Amilink, Sundance Q-Cut, TAO Editizer, United Media, Videomedia OZ--can control two (or more) source decks simultaneously. With two video sources, you can "mix" their signals to perform wipes, dissolves and even digital video effects (DVEs)--if you have a switcher. To take full advantage of the computer as edit controller, you need a switcher your computer can control.
There are basically two levels of control for a switcher. The simpler one uses a GPI trigger (WJ-AVE7 and MX-1). The switcher starts a wipe or dissolve when cued on the GPI (general purpose interface) line from the edit controller. More sophisticated control uses the RS-232 or serial port of the computer to send (and possible receive) info. Now the computer can send the specific wipe code along with the start time and duration; this code specifies the type of wipe, such as a horizontal "barn door" wipe.
Compatible Wipe Codes
Wipe codes are a problem. Every switcher manufacturer has devised unique codes for their many wipes. The Society of Motion Picture and Television Engineers (SMPTE) has recommended a set of standardized wipe codes; still, SMPTE could never provide wipe code numbers for the incredible variety of wipes available with digital special effects generators. Good software, like that from Future Video, simply includes huge tables of wipe codes for a number of well-known switchers.
If the switcher is inside the computer, compatibility problems disappear. RGB Computer's Amilink has complete control of all the NewTek Video Toaster wipes, dissolves, DVEs and unique organic effects. The Fast Video Machine is a complete DTV editing computer, thanks to the integration of its software with its own hardware--including the time base correctors (TBCs), audio mixer and full-blown production switcher.
Now that you've looked over the field of available edit controllers, ask yourself if you'll want more than just videotape control someday. Some of these edit controllers can expand to include new capabilities more easily than others.
You'll surely want titling, for example. Gold Disk's Video Director 2.0 has added titling capability to its software. To take advantage of it, you must invest in a genlock/overlay card. Integrating a switcher for A/B-roll editing is probably the priciest step. Check the list of switchers supported by the edit controller before you buy; also ask what other equipment you might need, like TBCs.
A good edit controller can make the difference between video dubbing (editing that consists of dubbing or copying occasional clips or whole tapes) and real video editing. Why not try a DTV computer as your controller? You won't be sorry.
Coming next month...the computer as a source of titles (CG) and graphic overlays. This has been a popular DTV use for computers, with add-in video cards like ADDA AVer, Matrox Illuminator and the Truevision VideoVGA, Targa and NuVista.
Videomaker contributing editor Bob Doyle directs a DTV group and a camcorder users group.