Computer Graphics World

June 2009 34 n n n n Trends & Technologies but it is the film industry's adoption that has spurred development and expansion of a more cost-effective and interoperable 30-bit color ecosystem. Championed by high-profile studios, with support from the computer graphics and display indus- tries, momentum for 30-bit color has been building along three fronts: the establish- ment of standards to improve interoper- ability, the dramatic improvement in the availability and pricing of 30-bit displays, and the emergence of comprehensive high- precision support in graphics hardware. Emerging as broad-based unifying stan- dards for the storage and transmission of 10-bit image data, OpenEXR and Display- Port, among others, are providing the glue that allows heterogeneous, multi-vendor 10-bit solutions to take hold. In the ab- sence of a formal 10-bit image format from the computer industry's de-facto standard, Windows, Industrial Light & Magic's (ILM's) OpenEXR standard volunteered to fill the gap. Adopted from the "half " data type of Nvidia's Cg shading language, OpenEXR's 16-bit floating-point format provides high dynamic range in a compact format, with a 10-bit mantissa to sustain 10-bit fidelity throughout the rendering and postprocessing workflow. With 24-bit color as the de-facto stan- dard for most display markets, video in- terfaces haven't formally supported 30-bit pixel formats. Yes, vendors can and do build 30-bit display systems around DVI, yet DVI has never officially specified a 10- bit-per-channel format, forcing providers to specify their own formats. e emergence of Video Electronics Standards Associations' (VESA's) Dis- playPort should improve the status quo. Showing promise as a unifying video in- terface not only to replace both VGA and DVI, but also to provide a cleaner path to HDMI, DisplayPort formally specifies a 10- bit standard format (as well as 12- and 16-bit formats shared with HDMI 1.3). DVI, on the other hand, did not. With a breadth of support across markets, DisplayPort should provide a lower-cost 10-bit alternative to SDI (and HD-SDI), an existing standard (ITU and SMPTE) confined today to high-end professional video applications. LCDs, Projectors, and GPUs Until recently, CRTs ruled the 10-bit dis- play world. Early LCDs couldn't match the CRT's affordability, nor did they measure up on critical metrics, such as luminance and contrast. Yet, just as the LCD has supplant- ed the CRT in virtually every other arena, it has done so, too, in the most demanding professional spaces and for both 10-bit gray- scale and 30-bit color applications. LCD technology, display quality, and volume manufacturing have improved to the point where CRTs are typically no longer considered for medical imaging applications. e LCD has even dethroned the CRT in its role as the de-facto standard for broadcast-reference monitors. Barco, a longtime leader in professional display products, recently introduced the first LCD monitor to achieve Grade 1 (EBU), a set of demanding specifications for bright- ness, contrast, and blackness. Similar to its rise in the consumer space, the LCD's momentum in professional mar- kets stems from its superior form factor and the dramatic reduction in price over time. Witness Hewlett-Packard's DreamColor LP2480zx display, a 24-inch, "color-criti- cal" LCD monitor designed in partner- ship with DreamWorks Animation. e LP2480zx not only displays 30-bit color images (10-bit per channel), but it can do so with custom presets calibrating the dis- play to the gamuts of seven-color spaces, including sRGB, ITU Rec. 709, and Ado- be RGB. With that image fidelity now available at approximately $2000, an LCD monitor like HP's will not only allow studios to real- ize that color-consistent, end-to-end digital vision, but it will open a lot of eyes in spac- es that haven't historically employed 30-bit color technology. And it's not just the ad- vent of high-quality, 30-bit capable LCD monitors on the desktop that promises to change the playing field for higher-preci- sion imaging. Rather, it is—perhaps even more so—the emergence of the high-reso- lution, 30-bit LCD projector, engineered to deliver better-than-film quality to the movie house. Of course, the display is only half the equation; 10-bit capabilities also must be up to snuff in graphics hardware. Fortu- nately, advancements in GPU technology in recent years have delivered just that, starting with the adoption of top-to-bot- tom 32-bit floating-point pipelines. Work- ing off the 32-bit architectural foundation, Nvidia and AMD have both extended pre- cision—10-, 12-, and 16-bit integer, as well as floating-point formats like OpenEXR's— through the GPU's back-end paths and out to the display. Early support focused on true 3x10-bit DACs and dual dual-link DVI ports, but today's GPUs are not only capable of driv- ing 30-bit digital display streams across A 24-inch, color-space calibrated, 30-bit color LCD monitor from HP, created in partnership with DreamWorks, makes color differences apparent.

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