Is the Answer 4K?
Several companies are currently working to make the 4K resolution format more accessible for both filmmakers and theaters. But will those technological breakthroughs trickle down to consumers in the not too distant future? And if so, "what is the next step in the evolution of home TV resolution?"
Let’s start with a little background. Early in the transition to digital cinema it was apparent that even the highest resolution specified for HDTV (1080p) was not really adequate to digitally project feature films in movie theaters. Both SMPTE and the Digital Cinema Initiative began work to define standards for digital cinema playback.
The specs that resulted from these efforts define both 2K, at 2048 x 1080, and 4K, at 4096 x 2160 resolutions. The actual pixel counts can vary depending on the aspect ratio in which the film is shot. The aspect ratio is typically not the same 16:9 used in HDTV. This means that a 2K projector can display 2.2 megapixels and a 4K projector can show 8.8 megapixels. At an uncompressed 24 frames per second, 2K needs 228MB/s and 4K needs 911MB/s.
Given these data rates, the DCI specifications allow for compression of the video data. Even with compression, current digital projection requires high performance fiber optic connections, heavy-duty processing power and a top-of-the-line 2K or 4K digital projector. Such a system is expensive and, as a result, there are currently only a limited number of theaters equipped to project 2K. So, at this point, why even think about moving on to 4K?
A digital photographer or audio engineer can explain that it is always easier, and usually better, to start out with more resolution than needed and then, if required, to resample downwards. It follows that a 4K source will look better sampled down to 1080p HDTV than direct 1080p HD video.
2K, and more commonly 4K, is also used as digital intermediates for post production work. A film will be digitally scanned for editing, color correction, effects work and the like. It is then transferred back to film for projection or sampled to 2K for digital projection or sampled down to make DVDs or Blu-ray discs.
With the availability of faster computers and cheaper storage, 4K is becoming progressively more practical. As a result, accessing the advantages of 4K are also becoming more practical and a transition to 4K is clearly underway. As a big example, AMC Theaters has struck a deal to convert the entire chains more than 4,500 screens to 4K capable Sony projectors.
OK, so 4K is great technology for studios and theaters. What about the at-home part?
Well, here is one item that may be indicative of a trend. RED Digital Cinema has announced a video player capable of 4K and 2K playback as well as 720 and 1080 HD formats from standard "DVDs." The feat is accomplished via wavelet compression encoding that is capable of getting 4K resolution down to as little as 10Mb/s.
This development demonstrates that technology is making real the possibility of home 4K players and network streaming of 4K resolution video. Although it is true that such video will look great down-sampled to playback on today’s HDTVs, the point is, however, that future home theaters may well be built around 4K flat panels or projectors.
It is worth noting that there is one current limitation in a transition to 4K. Today’s d-cinema projectors cannot process data fast enough to show a left and right eye images at 4K. A 4K projector can, however, project 3D at 2K resolution.
In any case, 4K may represent a way to future proof 3D content. It is likely there will eventually be projectors that can show 3D at full 4K resolution so audiences and distributors can both derive the benefits of 4K.
In conclusion, the current state of affairs has HDTV finally reaching the mainstream and Blu-ray still with a way to go before achieving mass adoption. While 3D in the home has the attention of most now, could 4K be the next wave after that? Or will NHK and its’ 8K (32 megapixel) broadcast approach become the next wave?
By Art Berman, DisplayDaily
