The amount of information our TVs are able to receive seems to move at a relentless pace. Not only are we inundated with new channels almost daily, but also the amount of pixels seems to rise exponentially these days. It hasn’t always been that way.
On the 3 November 1936 the BBC broadcast the world’s first ‘high definition’ TV show from Alexandra Palace, London. It was deemed to be high definition due to its then staggeringly high line count of 405. The previous TV systems had as few as 12 and then 30 lines and so stepping up to 405 lines was indeed a huge leap forward.
For many years TV broadcasting technology didn’t change that much until 1964 when the 625-line system was introduced. Broadcasting of 1080HD began in January 2004 with the digital service running alongside analogue. The switch over from analogue to digital ruffled many a feather as we changed TV sets or added huge sweating boxes of maths known as scalers and up-converters to facilitate the myriad of possible signals that were on offer.
Today, of course, the video world is a simpler place (oh no it isn’t, come on we’ve only just finished pantomime season) with analogue no longer relevant; no need to convert S video to RGBHV or HDMI, no longer are we making up component cables with those wretched BNC connectors on them.
Well it may be simpler in terms of the amount of connections but the new challenge of course is to understand the latest resolutions, how to display them and, most important, how to transport them.
Integrated Systems Europe is just around the corner and I wonder what new display devices will be unveiled this year.
Displays
CES this year saw Toshiba unveil a 5K screen, is this just a stepping stone to 8K? It is commonly known that broadcaster NHK from Japan is intending on using the Tokyo Olympics to broadcast using its Super Hi-Vision 8K technology. NHK have been involved with HDTV for many years pioneering an unsuccessful system called NHK Colour in 1972, which included 1125 lines and a 5:3 aspect ratio. 2015 is almost here, 2018 will follow at a pace and I bet some of you are designing systems right now that are due for completion in 2018. Have you considered how to transmit that 8K signal around the property? The screen resolution is just one element that makes up the overall size of the TV signal. SMPTE are targeting 120fps and have suggested that a frame rate as high as 300fps may be required to finally alleviate aliasing. Chroma sub sampling which is typically 4:2:2 or 4:2:0 currently may also rise to 4:4:4. What this really means is that we may have to deal with video transmission bandwidths as high as 142Gbps for a 4320p/120fps 4:4:4 video file. I can’t believe that we’ll need to deal with such large bandwidth requirements. Surely the eggheads will work out better compression methods. In the meantime, best practice design suggests that we need to be installing source equipment local to the display using high speed HDMI cables and for longer distances Cat-6a or even fibre. Remember, for HDMI cables, the longer the length the lower the bandwidth. Cable specifications, from one manufacturer, may change in line with the cable length, so check each cable before installing it in the wall.
Matrix switching and extenders
Running 4K over any distance will mean using active HDMI extenders or possibly a matrix. The use of a matrix, for now at least, will need a careful review of the specification. The new HDMI chip sets running at 300MHz (297MHz as a minimum) are the only ones capable of supporting 4K switching. I’ll be taking a good long detailed look at the specifications of anything I buy. Using HDBaseT as a method for moving the signal around a building seems to be a great solution. Coupled with active high speed HDMI cables I can begin to build a system capable of distributing 4K from a central location.
Codecs
As sure as 4K arrived this year 8K will arrive in a year or two and with the next jump in bandwidth there begin to be real concerns about using copper to move the signal around. That is one thing I just can’t see the eggheads losing sight of. H265 is already capable of supporting 8K including chroma sampling up to 4:4:4. Whilst this codec is relatively new having only been released in 2103 it looks set to be the answer to the bandwidth problem. Compared to H264 the new codec offers a bit-rate reduction of around 64% as shown by independent tests run by the BBC and University of West Scotland—that’s a big saving.
Conclusion
We are the experts in our field, it is what sets us apart from the box shifters and the bang ‘em and hang ‘em brigade, it is also why customers come to us. Being the expert means understanding the specifications from source all the way to display inclusive of cabling, looking down the tunnel and predicting what will come out of it, gazing in to the crystal ball to gain insight in to the next technical revolution. Luckily we can see the 8K train coming, think about it now, 2018 is not far away.
Simon Buddle is CEDIA's Education Director for the EMEA region.