Theres a lot of discussion about 4K--also known in the broadcast and consumer electronics worlds as UHDTV--production and whether it is practical for broadcasters to distribute 4K signals--it requires four times the bandwidth of current 1.5 Gbps infrastructures to get into the home. Broadcasters covering live events have utilized the technology as part of an overall HD sports telecast in order to provide viewers with captivating high-resolution, slow-motion replays and critical analysis of disputed plays.With little demand from consumers for UHDTV sets, however, it might take a while before we see activity in this space at the local OTA station level. Indeed, with 4K content now available on YouTube, its entirely possible that viewers will be watching UHDTV content via the Internet well before it can become a viable broadcast standard.
While high-resolution cameras, servers and encoders are now all readily available to produce such UHDTV projects, production switchers that support 4K natively have lagged behind, due to limited demand... until now.
At this years NAB Show, a number of companies will show new products that allow the switching of multiple 4K sources. The resulting production can then be distributed as either a single 3840 x 2160 image or a quad link (Quad Full HD, or QFHD, which is four separate HD images sent separately and then stitched together at the TV set).
Companies that offer HD video production switchers understand the current limitations and are taking a cautious approach with customers, admitting that such bandwidth-intensive signals are tough to handle with current infrastructures. These manufacturers include Blackmagic Design, FOR-A, Grass Valley, Ross Video, Snell and Sony-- all are working to develop single link methods of transporting UHDTV signals.
What is UHDTV?
According to Nigel Spratling, Marketing Product Manager for Communications, Switchers at Ross Video, these R&D activities include incorporating 4:1 compression schemes that would allow transport via conventional copper infrastructure, although this adds latency and additional processing requirements, and uncompressed transport via fiber optic link. In both scenarios, no standard has yet been established and thus current live UHDTV productions have used quad link transport techniques via existing 1080P 3Gbps interfaces.
The problem is identifying what is 4K, Spratling said. Yes, there are cameras and other pieces of gear available today in the market, but what version of 4K are they? What are the frame rates and how do they interconnect? Also, when you delve into how to create a production system beyond ISO capture and post-production tools, [how best to address UHDTV broadcasts] is very uncertain at the moment.
This scenario has made a big impact on how a production switcher made for 4K is designed and implemented. For example, using quad link means that the I/O size of a production switcher is dramatically reduced--a 96 x 48 3Gbps switcher becomes a 24 x 12 UHDTV switcher.
In addition, the current technique employed to manage signal switching, keying and layering is to combine the processing blocks of 4 MEs to create 1 ME in UHDTV. Therefore, a 4 ME 96x48 production switcher becomes a 1ME 24x12 UHDTV switcher. However, some quad link formats make it possible to also use a single link quadrant from a UHDTV input in another ME that is switching 1080p native signals.
The Ross Vision Octane 3G switcher is capable of 8 full MEs at 1080p.
The Ross Vision Octane 3G switcher is capable of 8 full MEs at 1080p. Therefore, it can be configured as a 2 ME UHDTV switcher or 1 ME of UHDTV and up to 4 more MEs of 3Gbps HD. The number of UHDTV sources connected will determine the inputs and outputs available for HD sources.
There is no doubt that a number of early adopters will implement this method of 4K production, Spratling said, however until the industry develops simplified interconnection techniques, UHDTV will remain in the future for mainstream television applications.
Low-Cost, Limited Option
Bob Caniglia, Sr. Regional Manager, Eastern North America, Blackmagic Design, said that at the NAB Show his company would show the ATEM 1 M/E Production Studio 4K at a low price of $2,500. The company said its ATEM 4K was the worlds first commercially available Ultra HD live production switcher.
Blackmagic Design began shipping the 1 RU high ATEM 1 M/E Production Studio 4K in the fall of 2013, and the ATEM Production Studio 4K in the summer of 2013. The 1 M/E version provides 4K switching through the use of 10 independent 6G-SDI inputs, each with frame sync. It also comes with built-in DVE with zoom, scale and rotate, four upstream chroma keyers, three independent aux outputs with front panel control, and a larger media pool that holds both still frame graphics as well as motion video clips.
The Blackmagic ATEM 1 M/E Production Studio 4K switcher costs $2,500.
We use 6G-SDI to connect Ultra-HD inputs to our products, Caniglia said. This new transfer protocol will let a director move between SD, HD and 4K all on the same BNC cable. You can run in 6 Gb/s and then switch them to 270 Mb/s standard definition speeds, 1.5 Gb/s regular HD-SDI speeds or 3 Gb/s 3G-SDI speeds. Broadcasters can build a system to switch from HD to 4K and back with different media with a couple of mouse clicks.
In fact, Blackmagic has built 6G-SDI capability into a whole workflow of broadcast products, including cameras, recorders, audio monitors, I/O devices, mini converters, and the Blackmagic Production Camera 4K.
Existing Workflow Integration
FOR-As HVS-4000 series of multiformat video switchers includes 2 M/E, 2.5 M/E or 3 M/E versions. These offer HD/SD mixed input, 3 Gbps support, 2.5D and 3D DVE, multiviewer, up/down converter, external device control, macro function and video file support. They also come with a
