All You Need to Know About 4K Ultra HD

 Although in my last blog I mentioned the different spec work currently underway at SMPTE, it’s time once more to take another look at 4K. 

4K

Current situation: HD is the new standard

High definition (HD) has reached European broadcast TV. It is now the new standard definition and considered to be mainstream. Having said that, at Belden we take into account that our professional broadcast customers may be managing two different HD formats.

The first of these is interlaced scanning with 720 to 1080 horizontal lines (e.g. 1080i). Each scan displays alternate lines in the image raster, and two complete scans are therefore required to display the entire image – also known as HD/1.5Gbps.

The other one is progressive scanning with 1080 horizontal lines (1080p). Each scan displays every line in the image raster sequentially from top to bottom – and is also known as HD/3Gbps. This format offers less jitter, with more stable and flicker-free video quality and sharpness. Because of the new 4K format, Belden uses the term 2K/3Gbps instead of HD/3Gbps.

Both HD formats are specified 2006 in the standards of SMPTE (the Society of Motion Picture and Television Engineers) under ST 292 for interlaced scanning and ST 424 for progressive scanning. These specifications are defined for 75 ohm coaxial cables and 75 ohm BNC connectors. By the way, ST 297 covers all SDI rates from 143Mbps to 3Gbps with optical fiber cabling infrastructure.

Most important for the broadcaster is to know how far he can transmit the signal over a single coax cable. Belden’s 1694A, for example, can have a minimum run of 113 meters with HD and 78 meters with 2K signals. These lengths can be improved when using our HD BNC connectors – for example 140 meter at HD or even further.  A Gennum chip produced by Semtech can extend this to 230 meters.

The future: Ultra HD,  Super H-Vision and Quad Full HD

When looking at the future, we can see two new formats. One is Ultra HD – also known as 4K/12Gbps (UHD-1) with 2160 lines and the other one is Super H-Vision – also known as 8K/24Gbps (UHD-2) with 4320 lines. Early adopters who aim to deliver UHD services in the next years may be confronted with limited capabilities in chip sets (e.g. to support higher frame rates). Therefore we can now see a third format on the horizon, called Quad Full HD – also known as QFHD/6Gbps with 2160 lines.

Learning from the past

Consumers already believed that HD was becoming mainstream as early as 2006. Four years later, the message was that 3D was rapidly becoming business as usual. But that was a misunderstanding. 3D was always a great experiment and it was certainly not ready to go mainstream. The professional broadcast market must be careful not to confuse the consumer again with a message that Ultra HD in 4K or even 8K is ready. It is still experimental. To move to these new formats, almost every bit of the production chain first has to adapt to the new format.

The near future

In principle, a good UHD service should consist of an optimum mix of increased resolution, frame rate, colorimetry and dynamic range. 4K would be the next logical step to provide a sufficient improvement over HD. Recent tests by Sony and FIFA of a 4K live production workflow at the Confederations Cup in Brazil 2013 have proven that 4K is operationally and technically feasible. To prove the capabilities of 4K Sony and FIFA deployed seven 4K Sony F55 cinema cameras  with an output of four separate 2K signals for transport at 3Gbps  (4×3=12 Gb/s) with the signals transmitted over 900m and routed through Miranda’s NVision video router. The tests demonstrated great improvements. This was the first time a multicamera production was in 4K and was run like an HD production.

4K: The cabling perspective

Looking at the market from a cabling perspective, 4K means that the bandwidth is growing, because 4K is 8 times HD and 4 times 2K. Today, the 4K signal is transmitted by using 4 independent connections, commonly called “quad-link”, in which each link is a 2K. That said, coax cable spec the same length as for 2K signals. It may be some time before broadcasters will be able to send a 4K signal down a single cable as a 12Gbps signal.  How long we will have to wait for this will depend in part on IC manufacturers, who today can only support QFHD/6Gbps signals. However, 4K signals could be supported in a “dual-link” mode (Semtech known as Gennum has such an equalizer), as broadcasters do with 3D today. It is a new technology and we will see over the next year what the market will drive, perhaps all change or we will start to see 4k as a compressed signal to make it fit into current infrastructures. All this remains to be seen at this time.

The good news is that coaxial cables can still support these high frequencies; they are physically robust and require simple connectivity. The use of single mode optical fiber cabling would also provide sufficient bandwidth to address the above applications. Although such interfaces are technically feasible, they are still very expensive to implement and require different capabilities, in terms of system design, installation, and maintenance, compared to the traditional coax and BNC infrastructure common today.

Stay Tuned! In my next blog, I will write more about coax cabling and explain how it will support 4K in the future.

For more information and samples, please contact Belden customer service at +31-77-3878-555 or drop me a line at werner.eich@belden.com










2 thoughts on “All You Need to Know About 4K Ultra HD

  1. Sergio Araujo says:

    necesito de su amable ayuda, necesito saber si Belden tiene un cable y un conector especial, para un cable BNC SDI 6gb/s, le agradezco su atención

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