X-Banned_Bob
Imported Account
Jan 22, 2004, 9:07 AM
Post #4 of 4
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Hey, no problem.
You know that composite video transmits all the sync, color and brightness signals through one wire (actually one set, including the ground).
YC is also known as S-Video and even incorrectly called SuperVHS at times. It's simply where the video signal is transmitted separately via two mini-coaxial cables combined in one cable. One set of wires carries the brightness signal (called "Y" or Luminance) and the other carries the color signal (called "C" or Chroma).
Component is where each of the signals from the Red, Green and Blue chips of the camera are transmitted on each of their own wires. This give the best separation of colors and definition.
The problem with Composite and YC is that there is still some bleeding of colors and mismatching between the the channels when the signals are combined. This makes it difficult for the software (or hardware) to determine exactly where the background color ends, and the foreground begins. Thus, many times the edges appear to have strange artifacts of the background color in them.
DV is better at the separation, since the digital signal does define the red, green and blue data separately in the digital code. The problem with DV is that the video is compressed via thousands of "blocks" within the pictures. Each block is larger than the individual pixels making up the image, but the colors and brightness are defined in such a way that our eyes see a sharp image. However, when the chromakey (or bluebox) effect is applied, these compromises to gain the 5:1 compression show up as the same garbage around the edges. Typically not as bad as Comp & YC.
All that said ... if you're getting paid for quality chroma key work and it needs to be perfect, the Casablanca series is incapable -- it just doesn't have the component I/O to make it possible. However, if it's just for fun, or low budget and a little garbage around the edges that's OK with a client, then go ahead and knock yourself out. In that case, the best would be to shoot some video like what you want to produce (both foreground and background) and rent or borrow a system for a few hours and check it out.
I hope this helps.
bb
: Alright, Banned Bob... I'm an ignorant sod; Would you be so kind as to define "component video system"..? Er, YC as well. Hey, you have to start SOMEWHERE, right?
: Thank you.
: : If you're gonna do serious chromakey work, you need to use a component video system of some sort. Composite, YC, and even DV still leave a ghost around the edges of the foreground subject at best.
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