Serious Magic's ULTRA 2, like the original package ULTRA, is remarkable for the ease with which a quality chromakey can be created. Imported DV—and now HDV—footage, graphic overlays, and even 3D animation files can be arranged with a few simple mouse clicks.
Most simple chromakeys are just four or five steps (including administrative or housekeeping issues like naming a file) from raw background and foreground images to a saved clip ready for output.
It can be just that simple.
But, if you love to tweak, ULTRA 2 will let you fine-tune to your heart's content. Keying parameters such as threshold, transparency, and alpha threshold can be modified with sliders and numerical input. Colors can be selected from a new color wheel and adjusted for saturation, hue, contrast, and more. Shadows and reflections can be placed with precision. Camera moves and virtual backgrounds can be incorporated.
All this and more can be seen in real time using the Live Preview function (using DV camera, PC, and a live input source). The right laptop will even preview ULTRA 2 chromakeys in the field.
ULTRA 2 is a standalone keying application; it's not a plug-in, and not a video editor. It is designed to work with existing editing tools (PC and Mac users can take advantage of all it has to offer) and it is compatible with a wide variety of video formats.
It's especially designed to deal with DV, of course, and the challenges that DV—even poorly lit DV—can pose to good chromakeys.
DV—Losing 2 to 1
Let's start with a little historical perspective: anyone remember those little buttons worn at industry events several years ago? Printed on the face were the numbers 4:1:1. Cutting diagonally across the front was the dreaded red slash. When DV was first introduced, waves of horror swept across the video production landscape, owing to the drastically reduced chroma (color saturation) content of the new format's video signal.
Until DV, most video was known as 4:2:2; green, red, and blue colors were sampled in that ratio. With DV, half the color information is tossed out the window—hence, 4:1:1. Now, with HDV, we are at a rate of 4:2:0!
Video folks said the DV codec would be brutal on colors, especially the keying techniques that depend on color, like green- and blue-screen chromakey. And for the most part, they were right.
Not just the reduced color information, but also other characteristics of the DV format were troubling: DV is compressed at a 5:1 ratio, using DCT compression. That means more challenges for effects-based production. DV cameras are light and inexpensive, but many are also rather lo-res, using CCDs with fewer pixels than in the past. That's tough on effects and compositing. Digital video processing, like pixel shift and edging, can do terrible things to video, from a keyer's perspective.
To counter these issues, Serious Magic ULTRA uses what it calls Vector Keying technology, a trademarked concept that uses special algorithms to analyze elements of a video scene, especially the background. Uneven lighting (hot spots, unwanted shadows or wrinkles affecting light reflection and therefore, key quality) is identified and compensated for during the actual key process. Spatial, chromatic, and temporal image information is assessed for artifacts and anomalies, and a range of key controls and image adjustments are applied as required.
Technicalities aside, what results is a nice, clean, tight key—even with poorly lit footage.