But even the largest of the studio-grade CRT-based direct-view HDTV monitors, Sony's BVMA32, measures only 32 inches diagonally, far smaller than a great many of the HDTV fixed-pixel displays already in homes. And while the image it can generate when reproducing HD video can be gloriously realistic — like looking through an open window — its relatively small size can hide defects in the image that may become obvious when enlarged in a home theater. Furthermore, since the BVMA32 costs $42,850, not all studios working on DVDs or HD video can afford one, with the result that many video-quality decisions are made using far less capable devices, all CRT monitors.

The research and development of all the major video-codec systems (MPEG-2, MPEG-4/H.264, and VC-1) used in DVD or high-definition media were conducted with images monitored on CRTs. Crucial decisions as to how these systems work, especially in how they're structured to minimize the visibility of encoding artifacts, were made using CRTs. So while it's hard to find an explicit expression of CRT technology in these video codec systems, their very architectures and operation were influenced by CRT characteristics, for good or ill.

This only starts to become a problem when you watch media at home. To the extent that your monitor or TV deviates from CRT-like size and visual behavior, you may see increasing problems with an image that looked fine when it left the mastering studio. I've found encoding artifacts such as mosquito noise and blocking to be more visible with fixed-pixel technologies than they are with CRTs of the same size, at least with material of DVD resolution.

What the pro-video folks desperately need is a fixed-pixel technology that produces very large, CRT-like images. Zworykin seems to have been prescient when he wrote 66 years ago: "Today, owing largely to the advent of cathode-ray television systems, a recognizable picture can be taken for granted, and the problem is one of obtaining a high-definition picture."

Back to Tech Talk Main
Back to Homepage
What's New on S&V

Print

Stumble It