Academic journal article T H E Journal (Technological Horizons In Education)

Desktop Video Goes Digital with Advent of Nonlinear Editing

Academic journal article T H E Journal (Technological Horizons In Education)

Desktop Video Goes Digital with Advent of Nonlinear Editing

Article excerpt

Digital video and its promise placing all the tools needed to make videos directly on the desktop--requires powerful computers with specific hardware and software to handle tasks like capturing video, compressing and decompressing segments, and storing and manipulating them. Though much is involved, these machinations are essential for nonlinear editing, the newest catch-phrase for desktop video.

This appears in more trade magazine headlines and sidebars than any other term, with the possible exception of digital video. Being well versed in both topics is virtually mandatory for anyone interested in creating educational or training tapes via computer.

* Wouldn't It Be Great...

A popular commercial begins with the words, "Wouldn't it be great if..." The desktop videographer's version of this might be something like this: "Wouldn't it be great if I could afford a system that would create a tape from source video files located on my computer? And wouldn't it be great if I could rearrange clips at will and develop different versions by simply inserting the segment of video, special effect or graphic I wanted at the point in the tape that I wanted it to occur? And wouldn't it be great if I could view my tape on my computer, in real time, to see if I liked it, then save it to tape at 30 frames per second?"

Well, the above is the rough definition of nonlinear editing, a technique wherein the ability to randomly access images from one's hard drive, rather than dealing with the linear containment of clips on source videotape, makes all the difference in the world. Of course, digital video plays a very large role here, thus the need for digitizing and codec (compression/decompression) products. One also needs internal or external devices to display the computer version of the tape on a television or export it to a VCR or VTR (videotape recorder).

The majority of nonlinear editing programs perform off-line editing, which means that the final product is not broadcast-quality video. What these programs do generate are EDLs or edit display lists--video scenes along with instructions for transitions, split edits, music, voice-overs and other extras--that are taken to a service bureau to be transformed into a polished final product.

"Many DTV turnkey solutions are on the market.

This procedure would be followed by universities and colleges interested in developing tapes for broadcast purposes--distance learning seminars or other instances where the tape would be broadcast to a mass audience.

However, off-line editors often print to video at 60 fields per second, which is true NTSC quality. While not broadcast-quality, it will be fine for those developing instructional tapes for classroom use.

Now that nonlinear editing has been explained, let's discuss how to configure a typical desktop video system for either DOS or Mac platforms, the amount of memory needed and the other pieces of this puzzle.

* DTV Ingredients

The software necessary to input and output video and audio fall into the categories of nonlinear editors, graphics and paint systems, and digital-video-effects (DVE) systems. Packages must be supported by hardware like encoders, decoders and digital filters to transform NTSC video into pixels, which can then be edited, combined with other video images and stored on a hard disk. Obviously, large amounts of storage will be needed; 1GB storage drives and roughly 16MB of RAM memory (for DOS computers) are suggested.

To create DTV on a Mac, opt for a model that sports at least one NuBus slot to accommodate any needed cards. Heavy-horsepower models like a Centris 650 with 8MB of RAM or more and a 300MB internal hard drive should do the trick. A removable storage device will also come in handy for transporting or archiving files; keep in mind that one frame of high-resolution, fullcolor video takes up roughly 1MB.

Many DTV turnkey solutions are on the market. …

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