Angshu Das, Consultant, Audio/Video Systems and Hardware Design Segment
The television industry has come a long way since black-and-white TV to color TV introduced in 1953. Digital signal processing happened in late 70s and digital transmission started in early 2000.
With the advancement of digital compression techniques, transmission of high bandwidth signals can be reduced considerably. This made the transmission of high-definition (HD) TV possible. It also led to a six-fold increase of pixels in HDTV than that of SDTV as picture became sharper. Two standards appeared: the 720p and 1080i/p. The 720p is 1280Ã—720 pixels and the 1080i/p is 1920Ã—1080 pixels. The aspect ratio for HDTV is 16:9 whereas it is 4:3 for SDTV. The 16:9 aspect ratios increased the horizontal vista enhancing viewing experince.
HDTV changed TV viewing experience for consumer and the demand for cinema-like experience in the living room increased. More pixels had to be transmitted to achieve this high resolution. UHD TV has 3840 horizontal pixels, which is twice of 1920 pixels of HDTV, and 2160 vertical pixels, which is twice of 1080 of HDTV. The aspect ratio is maintained at 16:9. On the other hand, the aspect ratio in 4K is 17:9 and it has 4096 horizontal and 2160 vertical pixels, which is perfect for digital cinema. The color space of 4K/UHD TV is about 76 percent of what the human eye can see as compared to HDTV, which is restricted to only 36 percent. This makes the picture colors lively and realistic. The frame rates of HDTV4K/UHDTV ranges from 23.976p to 120p. Such high rates provide smooth slow motion images even in fast-moving sports action.
Implication for Manufacturers and Broadcasters
4K produces high quantity of data, which needs to be stored, edited, archived, repurposed, and delivered to the consumer. Such huge storage and fast bit rates require reliable interfaces and storage devices. With the advancement of codec technology, bit rates can be reduced down to below 5 Gbps. ESata drives, SSD or Raid, arrays or USB 3, and Thunderbolt 2 interfaces are some devices which make working with 4K simpler. In the transition period from HD to 4K, 4K captured with HD delivery might have cost-cutting prospects for broadcasters. A single 4K camera is able to capture an entire scene; selective HD images can then be cut out to give a multi-camera effect. With digital zoom on a 4K image, tight HD images can be created from a single 4K camera. Similarly, with archiving and repurposing to multiple screens in different formats, it makes a lot more sense when the original content is captured in 4K. 4K is progressive and there is no irregularity encountered with de-interlacing. Progressive scanned images are being easily interlaced. Displays are progressive and so are web and mobile. No complex conversion is required except scaling.
UHDTV/4K changed the viewing experience for the viewers. Image size is bigger, pictures are sharper and lively, colors are vibrant, and watching wildlife, nature, or sports programs will never be the same now. But the real impact of these enriched improvements can only be experienced on large screen. While 4K/UHDTV is revolutionary, in India consumers are facing dilemma in the form of expenses and space they require to make it fit in their homes. Availability of 4K content is another dilemma for the success of 4K/UHDTV. With limited content offered currently, consumers are still not convinced for investing in an expensive UHD TV. Though 4K is a revolution for television viewers, Indian audience is still skeptical about making it a part of their daily lives.