The other “big thing” at InfoComm 2004 is projector manufacturers are finally delivering “widescreen projection” by actually shipping native resolution widescreen digital projectors. For the past 6 years, the projection industry has moved from analog projectors to digital projectors (the difference between your old TV and the computer screen you are reading this blog post on). Digital displays, driven by computers, use pixels as the smallest addressable display element. With the exception of workstation resolutions, computers and TVs have a display ratio of 4 units wide by 3 units tall; workstations have a ratio of 5 by 4. This gave us an SVGA ratio of 800 pixels wide by 600 pixels high, an XGA ratio of 1024 by 768, etc.
This all changed when HDTV ratio finally made it to the market. HDTV aspect ratio is 16 units wide by 9 units high. So what should the pixel ratio be? As you might expect, no one can agree. VESA (Video Electronics Standards Association) is still developing a standard. In the meantime we see projector manufacturers with the following pixel counts and ratios:
2080w by 1080h (16:8.43)
1920w by 1080h (16:9)
1366w by 768h (16:9)
1280w by 720h (16:9)
1024w by 576h (16:9)
964w by 544h (16:9)
Different resolutions arise from how manufacturers define “widescreen.” Which, in turn, is driven by the need to display Digital HDTV broadcasts and its inherent compromise due to the two different horizontal refresh rates. The two most common methods are 720p (scanning each line in progression) and 1080i (scanning every other line or interlaced). Computer manufacturers selling laptops with a whole other set of aspect ratios and resolutions further muck up the issue:
1024w by 768h (4:3) or (16:12)
1280w by 1024h (5:4) or (16:12.8)
1280w by 800h (16:10)
1440w by 900h (16:10)
1920w by 1200h (16:10)
By adding computer resolutions to the mix it is no wonder there are a wide range (pardon the pun) of solutions. And they keep changing — by the time you read this all of this may just be out of date! So how do projector manufacturers compensate for this apparent lack of coordination? Many up-convert or down-convert the signal to match the resolution of their projector. Christie Digital, for example, uses Digital Interpolation Technology (DIT) to manipulate HDTV signals from 720p to 768 (WXGA).
Since the FCC’s mandate for digital television has moved forward and stimulated interest in widescreen formats, many audiovisual systems are being designed and installed with widescreen display systems. Using a standard definition (4 by 3) projector on a widescreen results in black “pillars” on each side of the image. When widescreen material is presented on standard definition screens, black bars are located above and below the image. The problem arises when widescreen material is displayed on a standard 4 by 3 screen -with black bars at the top and bottom, the image is too “small” for the furthest viewer in the room. (Please see our January 2004 eNewsletter, “Presenting the Perfect Picture”, for more information.)
With new widescreen format projectors emerging, conventional wisdom has been that black bars and pillars would be a thing of the past. But different computer resolutions are making that virtually impossible. With all of these options, there may never be a widescreen standard. Manufacturers have been making progressive scan DVD players that can output 720p and are starting to produce DVD players that have an internal up-converter resulting in a 1080i output. If laptop manufacturers were to start producing laptops with a 1920 x 1080 resolution, we might obtain uniformity between the industries.