For the past 5 years, IP video has dominated the majority of surveillance system design, for a good reason; IP networks are the best way to provide remote access to a secured building’s video system. End users are also increasingly demanding High Definition (HD) video, and the migration to HD is now accelerating across overall surveillance equipment sales, as legacy sub-HD CCTV systems are upgraded to HD.
The HDcctv Alliance is dedicated to HD video transmission within secured buildings, typically between the cameras and a DVR/NVR that is locked inside one physically secure place. The goals for the HDcctv standard are PAL-like reliability, PAL-like convenience, and a PAL-like cost basis for high-fidelity HD video transmission. Furthermore, the Alliance recognizes that plug ‘n’ play interoperability is essential for broad-based acceptance of any technologies.
Surveillance video always begins with a television signal, and television is completely different from IP video. In order to take advantage of IP video, TV signals must be converted to Ethernet packet streams. The specialist thing that IP cameras do is convert TV signals to Ethernet packet streams inside the same box that originates the TV signal. The non-IP types of cameras get on IP networks via DVRs and IP encoders.
All cameras are designed to support IP video. The question is whether the camera converts the TV signal to an Ethernet packet stream or whether it relies on another system component to do the IP conversion. Converting TV signals to Ethernet inside the camera is handy in some cases, but it introduces certain disadvantages with respect to reliability, convenience, system cost, and live-view quality. For example, a certain degree of compression or Ethernet transmission latency is inevitable. Therefore, installers need to understand – and evaluate and adopt – IP cameras with a clear view as to what the particular application in question requires in terms of specific benefits achievable.
There are so many benefits of IP video for end-users. IP video is flexible and allows remote access to a secured building’s video surveillance resources, for example the video storage or analytics engines. Once those resources are available on IP networks, it becomes easy to integrate them with other aspects of the physical security system.
However, it’s important to recognize that IP video is not the same as IP cameras! Non-IP cameras are also capable of cost-effectively generating IP video via DVRs and IP encoders.
Within the security industry, there is a tendency to think that IP cameras are better than their non-IP counterparts. “All-IP-cameras” at first glance matches the compelling vision that the Internet eventually absorbs all electronics. Applying this idea too literally makes no more sense than doing word processing in your computer’s mouse. PCs are Internet-connected, and yet they still have HDMI ports and USB ports and analogue audio jacks; because Ethernet is not the optimum interface for every signal you need to work with.
A DVR in the secured building can be likened to your PC, and the cameras are peripherals. Such modular system architecture confers many economic benefits; you can upgrade to a better camera without losing or replacing your DVR, and you can take advantage of new compression algorithms in the DVR without having to change your still-fit-for-purpose cameras.
Nonetheless, 10 years ago the product management departments of major manufacturers were attracted to “running IP to the edge” with IP cameras. In many ways, this rush to all-things-IP was understandable, as all businesses invest strategically in IP technology and products. IP cameras became especially compelling when customers who were willing to pay extra for HD surveillance had no other viable HD alternative.
The IP camera sales expectations were supported by market research analyses, and, although those projections have not come to fruition yet, these companies’ commitment to IP cameras was significant and early. It is understandably difficult for a manufacturer to change direction, or to be open to alternatives, once the ‘IP only’ agenda has been set. Embracing a new alternative could be seen as discounting the many man-hours invested in the strategic objective of adapting Ethernet for local-site HD surveillance video transmission.
Highly integrated security systems rely heavily on IP network communications, and the industry has been adding IP video capabilities to security systems using all sorts of cameras, and DVRs and IP encoders are cost-effective IP network on-ramps. In addition, IP cameras can be a particularly good fit in a new building, where a high-reliability, high-performance surveillance LAN can be installed at the same time as other business LANs.
However, fewer than 15% of all surveillance cameras sold in 2013 were IP cameras; users of the remaining 85% also deserve the opportunity to work with the best possible images manufacturers can provide. Many of the legacy systems have been adapted to IP networking, and there are now solutions that allow a system to include all sorts of cameras – including both non-IP and IP.
There is an array of technology solutions on the market for transporting HD video within secured sites. You can break them down to three major technologies for local-site HD surveillance video transport:
- Digital Ethernet
- Digital HD-SDI
- Analogue HDCVI
Today’s HD video transmission technologies are based on Ethernet, HD-SDI, and HDCVI. Each of these technologies has advantages and limitations. Ethernet has been used by IP cameras for nearly 20 years now. HD-SDI, initially developed for broadcast TV studios, came to the surveillance market under the HDcctv 1.0 standard in 2010, and an enhanced HDcctv 2.0 is in the process of being ratified. HDcctv 2.0 NR DVRs and cameras offer the same digital perfection as HD-SDI, with plug ‘n’ play up-the-coax remote control. HDcctv 2.0 AT, based on HDCVI technology, delivers true HDTV signals over any legacy CCTV cable, with plug ‘n’ play up-the-coax remote control.
It’s important to realise that each of these technologies have advantages and disadvantages, and there is no one ‘best solution’ that fits every situation. It is extremely important for video surveillance system designers to understand each specific circumstance within their projects and choose the technology that fits their requirements accordingly.
Ethernet enables transmission of images in arbitrary formats and encodings, making Ethernet the only viable solution for capturing arbitrarily high-resolution images. In other words, IP cameras are the right choice for video with a resolution above 2 million pixels per frame (1080p25/30 formats).
With Wi-Fi being the most cost-effective wireless transmission technology, IP cameras are also the appropriate solution in situations where power can be applied to the camera but no signal cable is available.
There are various local-site transmission technologies that enhance and support IP video. Local-site transmission technologies are completely independent from IP video; IP video is used for remote access in all cases. The difference between IP cameras and non-IP cameras is the choice of where on the local site TV signals are converted to Ethernet packet streams. Separating the camera, which converts light into TV signals, from the IP conversion, is a modular approach that saves system costs and increases flexibility and scalability over the lifetime of a system. It is therefore a way of future-proofing the solution
There are many more situations where IP cameras are a good engineering choice, but it is worth remembering that the non-IP HD transmission alternatives also offer obvious advantages with respect to reliability, convenience, make-cost, and video quality. The focus should be on producing the desired results for the end user, and this means selecting the most appropriate technology on a per-case basis.
The fact remains that no resolution will be ‘enough forever’. The desired results will be achieved via whichever means is most suitable for a given project, and whichever means provides the best cost/performance trade-off for the end user. The market is going to see local-site Ethernet transmission continue to gain market share as an option suitable under certain circumstances; while HDcctv transmission methods will continue to provide a compelling alternative for a huge number of end users, based on reliability, convenience, make-cost, and real-time performance.