Is 4K video a valid surveillance tool?
The video surveillance sector has largely adopted HD video as its de facto standard, and many installers and integrators are seeing user demand for anything of a lower quality fall off a cliff! Just as consumer sector trends meant that customers were understanding of the benefits of HD video, so the emergence of 4K TVs and video sources is pushing forward demand for UltraHD resolutions. Benchmark considers how 4K video will impact on the security and surveillance sectors.
If you think back to a few years ago, the video surveillance sector was heading towards a megapixel future. In an approach that seemed almost oblivious to developments in the consumer sector, manufacturers of devices and systems were predominantly focused on the delivery of solutions which generated and managed 4:3 megapixel video streams.
At the time, it could have been argued that the move made some sense. The majority of monitors suited to security applications (those designed for heavy duty cycles) used the 4:3 aspect ratio, most NVRs recorded 4:3 video, and the HD format was viewed by some as a consumer market option. Additionally, with a 4:3 legacy across the surveillance sector, even some leading manufacturers declared that HD could be a limitation rather than an advance in terms of performance.
History shows a large number of technology advances which were influenced more by public demand than by potential performance. The most glaring example was the VHS versus Betamax battle. Technologists will always acknowledge that the superior system, in terms of performance, lost out due to marketing reasons. Once companies in the VHS camp secured the rights to the back-catalogues of some of the most prominent film studios, the format war was over. This isn’t to imply that 4:3 video was superior to 16:9, but to acknowledge that once the public psyche had accepted HD as the future for video, nothing was going to persuade them otherwise.
Public appreciation of HD, and demand for the format, steered the security sector towards the proliferation of HD systems we see today. While some users were unimpressed with 1.3 and 3 megapixel devices – after all, their phones had better quality cameras – they accepted HD720p and HD1080p, despite these being less than 1 megapixel and 2 megapixels respectively! HD video had become so much more – in their minds – than a resolution.
HD video has become well-established in the surveillance sector, and this has allowed the security industry to leverage economies of scale with regard to peripherals such as displays, codecs, etc.. It has also brought security into line with public expectations.
When looking towards the next ‘big thing’ to migrate from the consumer world to the security arena, some declared 3D would have a significant impact. Such claims represented little more than clutching at straws. There was never any benefit to be realised from 3D surveillance. Of course, 3D technology has even struggled to become established in the mass market.
The current next-step technology is 4K video, or ultra-HD. This technology does offer a number of benefits to surveillance users, and will definitely change the way many solutions are delivered.
The 4K charge
In the world of consumer video, 4K isn’t about to become the next big thing. It isn’t a future technology awaiting delivery. It is here. Not only has 4K video arrived, but it is being embraced by the public, by businesses and organisations, and by a growing number of manufacturers in the surveillance sector.
Like HD before it, ultra-HD encompasses more than just resolution. In reality, ultra-HD is much more than 4K; it is a common grouping that includes 4K UHDTV. Streams of 4K UHDTV deliver resolutions of 2160p (3840 × 2160 pixels).
A note for the purists: 4K UHDTV is referred to as UHD-1, because the simpler 4K designation is used for a DCI standard in digital projection which has a different resolution and aspect ratio. In truth, it’s unlikely you’ll see DCI 4K outside of the cinematographic world, so confusion won’t be an issue!
Like HD, 4K UHDTV is a standard. However, it’s an evolving standard. In terms of frame rate and colour fidelity, installers and integrators can expect the same specs as HD as a basic minimum. Manufacturers are using the step to 4K to reconsider many aspects of video performance, and high on the wishlist are increased frame rates, wider colour spectrums and enhanced contrast.
This will also have an impact on connectivity. Whilst HDMI 1.4 will support 4K video at 25fps, HDMI 2.0 will be required to deliver 4K video at 50fps. As monitors and recorders become more prevalent in the security industry, it will be vital to ensure that the latest HDMI variant is supported!
A better view?
There is an inherent truth when designing any video surveillance solution, regardless of the technology employed. Whether analogue or digital, 4CIF or HD or even 4K, the system will only be as good as its lowest performance element. Taking a short cut at any stage of the solution will limit what is possible.
With that said, it is unlikely that many systems will switch to using 4K technology in the same way that they currently use HD video. Whilst the first 4K NVRs and surveillance-grade monitors are being shipped, choices are still limited.
An HD-to-4K transition would require new cameras and lenses, new recording hardware, enhanced storage facilities, replacement (often larger) monitors, better bitrate management via advanced compression algorithms, etc.. This isn’t to say that the issues will be addressed, but the situation does restrict the potential for end-to-end 4K systems today.
Before moving on to how the surveillance sector can utilise 4K video, it is worth commenting further on the statement that larger monitors would be required. A brief look at the availability of 4K displays will highlight one issue: sizes tend to be 48 inches and upwards. There is a simple reason for this: the Lechner distance.
Research has established that when a screen is either too small or too far away, the human eye cannot appreciate the additional quality which is realised by 4K video. Therefore it is possible to create a system which is 4K throughout, but which does not deliver enhanced quality to the operator!
There are some in the security industry who question the role of 4K video at present. There are even some who question its place in surveillance in the future. It is true that 4K video presents a number of challenges. With a resultant image approaching 8.3 megapixels, and a standard that may end up pushing towards 50fps, it will undoubtedly challenge thinking on streaming and archiving video.
Work on H.265 is well underway, and advanced intelligent bandwidth management technologies are emerging both in the security and IT sectors. Storage costs are decreasing while options are increasing, so the predicted technology gulf is shrinking.
However, 4K video can add benefits today, in spite of the restrictions that currently exist. The key lies in the increased resolution.
When HD first arrived, many manufacturers highlighted the ability to digitally zoom an image without losing detail. It was, at best, something of a mediocre feature because once zoom went beyond x2, you were viewing images below the quality of an analogue system. Where 4K makes more sense is that the amount of available digital zoom is increased.
However, whilst digital zoom will inevitably be mentioned by manufacturers, the real benefit with a 4K video stream is the ability to generate an overview of a large area, whilst also creating ‘virtual cameras’ using regions of interest. For example, high risk elements of a scene – entry and exit points, cash handling facilities, no admittance areas, etc. – can be selected and individually streamed at high resolutions and at required frame rates.
Increasingly, the use of multi-streaming technology could also allow these regions of interest to be managed and recorded by a VMS as different and distinct cameras, thus allowing resources to be adjusted according to risk levels.
There will be the inevitable claims that a single 4K camera can replace more than 20 4CIF units. Such assumptions are misleading, and would require the cameras to be installed in a block, thus creating a larger image area. This is, of course, ludicrous in reality. However, by isolating specific areas of a scene, there is certainly a good case for a 4K camera to replace a number of cameras with regions of interest whilst also delivering an overview of the full area.
There is no doubt that visually, 4K delivers increased detail, often to a higher level than many will anticipate. There have been claims made – admittedly from outside of the security sector – that 4K video streams, recorded as 4K but downsampled to 2K (HD1080p), show increases in image detail and clarity.
At Benchmark we don’t believe anything until we’ve tried it ourselves, but it is true that 4K video does capture some of the finer details that even HD video struggles with.
A brief look at products and systems on offer shows that 4K cameras currently outweigh recorders and monitors in terms of supply. Even lenses are slightly behind the curve. That said, the situation reflects the early days of HD adoption in the surveillance sector when cameras arrived long before other devices.
Despite this imbalance, it doesn’t mean that the benefits of 4K video are out of reach for now. If anything, there are many applications that could benefit from the technology today, and would also be moving towards a more future-proofed situation.
To exploit the added value of 4K may require a different way of thinking, but that in itself is no bad thing if enhanced security can be realised as a result.