- Written by Ofer Laor
- Published on 03 October 2012
The Darbee Darblet DVP5000 Video Processor Design
What is a Video processor?
I guess the first question that one needs to ask is what is a video processor and why would one need such a product? The purpose of a video processor is to squeeze out every bit of potential image quality from your display or projector (the processing, deinterlacing, scaling part of the processor), all the while trying to get as close as possible to imaging standards (the CMS part of the processor). VPs also have other features, such as picture in picture, switching converting and splitting HDMI connections.
The original need for video processors started in the CRT projector era. Back then, these were the best projectors money could buy. They had their problems (convergence, geometrical issues) but the contrast level was legendary. As people started getting the hang of these projectors, they started enlarging the image more and more. These projectors did not produce pixels as we know them, but had scan lines that worked their way from left to right blanked and returned back to the left. The source material was 480i, which meant that each scan line had to do 240 rounds for even lines and then 240 more for the odd. That left quite a bit of a gap when enlarged to a large (even at 50" or so) screen size. Line doublers first repeated each line twice, but that did not really improve things. Then bob/weave algorithm based doublers came but didn't really improve resolution by much.
The big breakthrough came when Yves Faroudja came up with an ingenious patent for retrieving the 3:2 telecine sequence that film content went through in order to convert it into 60Hz content. The sequence caused a minor glitch, a repeated field once every 5-field sequence. Once Faroudja's line doubler picked up on it, he could reproduce the sequence and reproduce the original 24FPS content in all its progressive 480P glory…
Add a scaler to that and you get Faroudja's original DVP5000 masterpiece processor. Unfortunately, once Yves sold the company, Faroudja slowly faded away after selling many chips to DVDs, displays and AVRs that basically reproduced these algorithms.
And then came HD.
The time between SD and HD was the golden age of Video Processors. 1080P displays were coming out in droves, but the content was still not there. Scalers were able to upscale the content and make it worthwhile to see on these large projectors and flat displays.
However, as time went by and Bluray content proliferated, the need for a dedicated processor became more and more the focus of videophiles rather than regular folks who would do just fine with the processing abilities in their projectors or AVRs.
VP manufacturers added more features, such as cleaning compression artifacts, Color Management Systems (CMS), calibration features and more. But these were focused on the niche high end videophile market.