UHDV and 4K Projectors
By Cliff Roth
With almost identical resolution to the new UHDV format, the best 4K projectors used in digital cinema movie theaters for digital projection of popular films have offered a somewhat similar experience for over a year. Sony's SRX-R110, for example, was introduced in 2004 and features 10,000 ANSI lumens brightness and 4096 x 2160 resolution. It's recommended for screens up to 40 feet wide.
So what's the difference between UHDV and 4K? Technically, on the display side, there may not be much distinction. In terms of how these technologies will be deployed, however, there are big differences.
4K is considered a strictly professional format, and Hollywood movies distributed to Texas Instruments' DLP and Sony projectors utilize proprietary high-security recording formats with minimal data compression.
UHDV is a more comprehensive format, in that it includes audio. 4K is strictly a picture format, although, of course, it's fully compatible with Dolby Digital, THX and all other audio-for-film formats.
The frame rates are different. UHDV attempts to create a simulated-reality visual experience, with a very fast refresh rate designed to make it indiscernible—60 fps progressive scan. The digital cinema systems, by contrast, maintain the same 24 fps rate of theatrical film. The goal for 4K is not so much reality as to mimic the film experience with video.
Viewing angle would also appear to be different, at least in terms of intent. In movie theaters, the rule of thumb that Hollywood requires is a minimum of 30 degrees horizontal visual angle from the very back row of the theater. While adequate, this is a far cry from the 100-degree visual field that NHK says is necessary for UHDV. Of course, how far the viewer sits from a screen is also under the viewer's control, and moviegoers who sit in the very front rows of the theater may indeed get the full 100-degree immersion.