Not All 4K is created Equal

I was at IFSEC 2014, where Ultra HD / 4K cameras made their first major public appearance in the UK, There was a lack of knowledge and misinformation when I approached multiple manufacturers’ and distributors' stands.

All I got was conflicting opinions and it was obvious the majority didn’t know what their product could do – in a lot of cases this was probably because they were talking about products that didn’t even exist; or even worse, they didn’t know the differences themselves. CCTV security has adopted various technology standards and formats over the last 20 years, analogue being one of the first with 640 x 480 pixel VGA format as the most common. This is where technology was at that time – then meg pixel cameras started appearing in the market ten years ago starting at 1 Megapixel quickly going to 3 Megapixel and now we have 29-plus Megapixels cameras readily available with prototype cameras with gargantuan Mega and Giga pixel capability. Megapixel and the multiple options of sensors formats and lens sizes did much to confuse the majority of end users not to mention installers and consultants alike; giving them a glimpse of what could be, but not clearly outlining any of the pitfalls.

 

Picture quality in some specific cases can undoubtedly be excellent with all these technologies, even old analogue. But there are a number of factors that affect picture quality besides the image sensor (as there are multiple sizes for megapixel sensors), other issues such as lens type, zoom capability, available light and weather; all have a major bearing on picture quality and need to be considered. All these factors together can make it hard to identify from what type of camera a picture or image originally came from. A lot of the technology for the security and CCTV marketplace came from two distinct areas: the photographic (cameras) and the broadcasting industry (TV), which has caused some confusion, especially in screen formats. The photographic industry uses multiple size megapixel chips, to suit camera market segments from compacts to high end DSLRs [digital single-lens reflex]. They use different size chips but of the same megapixel rating – size of the sensor is a major differentiator. Megapixel size might purport to be the same across all cameras such as a range of 10-18 megapixel cameras but with vastly different pricing and image quality; the critical consideration is sensor size. Aspect ratios are different from HD / Ultra HD (broadcast standards 16:9- widescreen TV) and Megapixel 4:3 being the most common used in the photographic industry.

Camera sensors come in different sizes all with the same Megapixel rating! Putting it in simple terms the major difference is the size of the sensor, which affects light sensitivity and is reflected in quality of image produced; this in turn is reflected in the price. Megapixel cameras come in different flavours; all have the same megapixel rating but quality of image can vary radically. The size of sensor has a direct correlation to the amount of light gathered and quality of image produced all the above have the same megapixel size and can use a 4:3 image format.

World after HD


Then HD exploded onto the scene! On your widescreen TV (Full HD 1920 x 1080) – All of a sudden everybody got it: “I want THAT picture quality”! Excellent picture quality in their own home that mirrored what they were already getting from their phone or iPad; pictures from most existing old analogue cameras looked inferior and dated – for some it was a revelation and an expectation was set of the minimum level of picture quality that was now always expected from their CCTV as a default! So the market had spoken with their feet; a broadcast standard rather than one of the multiple CCTV standards was the yardstick for everyone to follow this has become. A plethora of HD CCTV cameras manufacturers followed on the market at cost effective pricing all following the broadcast standards and driving pricing down. Then came Ultra HD 4K (3820 x 2160) following the HD broadcast standard with something better than HD! Ultra HD/4K: basically it is a 12 megapixel image (4072 x 3076) cropped down to 8.3 megapixels (3820 x 2160) to fit on all wide TV 16:9 display formats.

 

 

Another broadcasting standard, I hear you say that is already in place; yes! And there is also an 8K standard (Super Ultra HD?) a massive 7680 × 4320 – or 33.2 megapixels per frame broadcast standard already available and 16K to follow. These are too expensive for mass adoption within the CCTV marketplace and could easily choke up network infrastructure if multiple cameras were on the network. So we now have 2K, 4K 8K and 16K broadcast standards already in place and because of the size of the broadcast industry compared to the security industry a question you should ask yourself … is the security industry going to follow? CCTV standards reminds me of the great VHS standards battle of the 1970’s where we had: Phillips N1500 standard of 1972; VHS (JVC); and Sony’s Betamax standard. Once the industry chose VHS it was immaterial what was the best; a standard had been se,t the rest as they say is history. In unison with these changes within the CCTV industry Ultra HD/4K developments the costs of PC servers, processors, RAM memory and hard drives has been plummeting with 1-4 terabyte disk drives and quad core processors becoming cost effective so making the move to ‘high quality video’ even more appealing and affordable. One major consideration is if you run these cameras on your corporate network what impact will it have on bandwidth?

More confusion?
The 4k Ultra HD CCTV camera standard has created a bit more confusion because of how all CCTV manufacturers address these new broadcast standards, and the inherited amounts of data that these images create. If implemented incorrectly it can have an enormous impact on bandwidth and network traffic, not to mention required storage. Each manufacturer follows the H.264 data compression standards but sometimes not fully or they strip out some of the features of H.264 which makes them ‘slightly non-standard’ and this can impact on options available and communications with the Video Management System (VMS). A question you need to ask any prospective camera supplier is: what is the file size of an individual frame or picture coming from their megapixel (8-12MP) camera at maximum frame rates? This file size can vary dramatically camera to camera and depending on how the manufacturer encodes and follows the H-264 standard. This could have a major impact on storage and network traffic. File size is the major issue on storage and bandwidth needs especially when you are looking at one to 30 frames per second and with many cameras – the answers you get from individual suppliers is varied and sometime guarded, so as not to highlight major storage or communications issues in large deployments. Remember, more storage and bandwidth directly equate to more money or need for potential network upgrades to manage additional network traffic.

Other major issues to consider are: lens type, which image sensor is being used and the need for it to be specific to Ultra HD 4K! How many streams of data are coming out of the individual camera – one, two, three or four – is another consideration that on face value look unimportant as does what format, that is, D1, 720,1080 or Ultra HD 4k for each stream. This could have an impact on operational bandwidth usage and network traffic. Why do you need multiple streams? Correct lenses maximise image quality and range, multiple streams give you the ability to reduce network traffic by sending smaller images to fit in a non-Ultra HD/4K device or screen or into just part of the Ultra HD 4K monitor rather than sending the FULL Ultra HD / 4K image file when it is not needed, thus helping to stop unnecessary network traffic at its source. This is most useful when you have a video wall scenario and are viewing multiple cameras. This is important in control rooms where you need to view multiple cameras at the same time and you have a HD or Ultra HD /4K screen to view all the cameras on the screen at the same time – the screen has to handle, say, multiple Ultra HD 4K cameras so it reduces the format down so as to fit in that tile. If cameras can send this information other than at full format you are helping to avoid creating unnecessary network traffic and will increase speeds across your network. There is no point sending a huge image across your network or to your servers when the target device may not need it.

Some Video Management (VMS) systems are smart; they work out which stream you need on the fly to fully optimise your network and storage usage; thus no unnecessary network traffic increasing speed and reducing overall storage requirements.

What’s the difference?

What’s the difference between HD and Ultra HD? A picture as they say is a thousand words. For evidentiary purposes Ultra HD/ 4K footage can make a difference in identification when compared to HD observational quality and should increase conviction rates. As no one has ever been convicted on live footage – recorded Ultra HD 4K footage gives greater and more detailed picture quality when matched up with the right lens – as storage becomes cheaper it make more business sense to go with the highest quality image system.