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What is MPEG-4?

MPEG-4 is an ISO/IEC standard developed by the Moving Picture Experts Group (MPEG), the group that also developed the MPEG-1 and MPEG-2 standards. These standards have made applications such as CD-ROM interactive video and digital TV possible. MPEG-4, otherwise known as ISO/IEC 14496, became an International Standard in 1999. The fully backward compatible extensions under the title of MPEG-4 Version 2 were frozen at the end of 1999, in order to acquire the formal International Standard Status early in 2000.

MPEG-4 provides standard components enabling the integration of the production, distribution and content access for digital television, interactive graphics applications and interactive multimedia.

IP Video Oliver Vellacott, CEO of IndigoVision, presents an overview of IP Video and discusses some new developments The IP Video market is growing rapidly, having been accepted as a mature technology with a field proven record. IP Networking of security systems will eventually penetrate the majority of the market – it has too many cost and performance advantages not to do so. Why IP Video? The advantages of IP Video can best be highlighted by looking at the disadvantages of analog CCTV. In many ways traditional coax or fiber based video systems are limited. Installation costs over large areas are prohibitive and the number of monitoring stations is limited due to the investment required to replicate costly switching infrastructure. The analog matrix is the component that provides control room flexibility for analog CCTV systems, but this too cannot be easily expanded without adding new hardware and it is location dependent. Therefore overall scalability, i.e. the cost of expansion, is poor. Even though the introduction of DVRs has improved the recording capabilities of analog CCTV, these too are limited. They have to be physically installed near the analog matrix, and frame rate and image quality is often compromised. Businesses want a single, scaleable, integrated solution which provides high-quality video surveillance across any number of their offices or sites – this is what IP Video delivers. For enterprise systems IP Video also offers a high level of redundancy. In the event of an emergency the control and monitoring capability can be easily transferred to any other point on the network either on or off site. Redundant networks allow the system to keep operating even if one link or switch goes down and redundant NVRs allow recordings to survive even if one recorder fails or is destroyed. These features allow IP Video systems to deliver a level of integrity far higher than is possible with analog CCTV systems. Having everything based around a network allows system wide diagnostics to ensure everything is running smoothly. Every device can be continuously monitored and an alarm raised if anything fails. This is not possible with an analog system where camera feeds have to be manually monitored to ensure trouble-free operation and the potential exists for a fault to go unnoticed for a long period of time. This is particularly an issue with DVRs, as a fault will not necessarily be flagged and recordings for all cameras could be lost, again for a long period of time. Analog systems can implement limited diagnostics but this depends on the different components used and is not an integral part of the system. Building an IP System - The Virtual Matrix The key component in an analog CCTV system is the matrix. In an IP system, the network and the software controlling it becomes the so called ‘virtual matrix’. IP Video systems operate over standard corporate networks. As these typically span entire organizations, so can IP Video systems connected to them. As the traditional control room equipment can be replaced by a PC it is possible, and often desirable, to be able to monitor live and recorded video from any camera from any point on the network. Each camera is connected to the network via a transmitter/receiver unit that compresses the analog video into DVD quality MPEG-4 digital video for transmission over the network (see sidebar - What is MPEG-4?). The digital video can then be viewed, analyzed and recorded. This is achieved with Windows based PCs running video and alarm management software and Networked Video Recorders (NVRs) that are installed around the network (see Video Recording below). As access to the system is available from any PC connected to the network, IP Video systems implement sophisticated ‘User Profiles’ to manage this. These restrict or enable access for users on a camera by camera basis.

The transmitter/receiver units allow any type of CCTV camera to be connected to the network, ensuring existing equipment can be fully utilized. However, for new installations one option is an IP Camera or Dome. These combine a professional full-function high-quality CCTV color camera with an IP Video transmitter/receiver in one unit, which can be connected directly to the network. Significant cost savings can be achieved by employing the integrated camera units in place of traditional analog video cameras and a separate IP transmitter/receiver unit. There are now many different IP-ready products available from different manufacturers, including IP cameras and DVRs with network connections. However, the only way to ensure compatibility and to get the most from the advanced features that IP Video has to offer is to use a single integrated system from one manufacturer.

Designing a System - Network Requirements Manufacturers of IP Video equipment provide excellent tools for helping security and IT professionals design digital CCTV systems and in particular compute the bandwidth requirements of the network. It’s fundamentally a very simple process; decide how many cameras are required, decide what video quality for viewing and recording is required and decide how many days of recording are needed. These can then be used to calculate how much bandwidth and recording storage is required. Each device connected to the network is then assigned an IP address, ensuring they are all on the same sub-net and can therefore ‘see’ each other. The ‘Site Builder’ software tools provided then interrogate the network and discover all the appropriate devices and automatically build a site database and recording schedule. In many cases the bandwidth requirements can be easily accommodated on the existing corporate LAN/WAN, giving the proposed IP Video system another significant advantage over analog CCTV by removing the need for additional cabling. This also means the network can be shared with the normal IT traffic and facilities such as Voice-over-IP. IP Video has many clever features which ensure that the bandwidth impact is kept to a minimum. Positioning NVRs locally to relevant camera clusters can reduce network traffic and improve redundancy. The compressed video can be transmitted across the network using TCP, UDP Unicast or UDP Multicast protocols. The advantage of Multicast is that it uses the same amount of network traffic for 1000 operators to view a camera as it would for one operator. Activity Controlled Framerate (ACF) is another feature designed to reduce network traffic. This facility relies on processing data at the camera IP transmitter/receiver unit. If no movement is detected in the camera scene then the bandwidth used is dramatically reduced. This feature is most effective in places where low activity occurs, such as in corridors, on fire escapes, or in buildings which are unoccupied at night. Searching recorded video can be a time-consuming activity with a corresponding increase in network traffic. However, clever thumbnail search facilities can be provided by the video and alarm management

The typical NVR solution simply requires a PC platform and hard disk storage. However, for more demanding fault tolerant applications NVRs can be packaged in stand-alone units with removable hard disk drives.

Transmitter/receiver modules transmit MPEG-4 quality digital video, audio and control data over the IP Network.

software. The system can analyze movement in a scene and display thumbnail images that represent frames from recordings containing the specified movement. Clicking on one of the thumbnails then replays that section of video. This feature can search 24 hours of recorded video and display the thumbnails in just a few seconds. Changing the search variables allows the operator to sift through vast quantities of recorded material quickly and efficiently. The use of thumbnails allows a vast amount of video to be analysed with little extra impact on the network. Don’t Throw Out the Old Cameras – Handling Legacy Systems It is clear to see the advantages of IP Video for large enterprise systems, with its underlying flexibility and scalability. However, it is also an ideal solution for smaller CCTV systems and in particular for upgrades to existing installations. When upgrading from an existing analog system the obsolete equipment such as the matrix and DVRs can be replaced, but all the cameras, domes, monitors and keyboards can be kept. Using IP transmitter/receiver units, all existing cameras and monitors can be interconnected; in fact existing control room configurations can largely remain unchanged. With the addition of a PC or two, all the advanced features of IP CCTV can be made available without the need to change the familiar surroundings of the control room. Once the migration is complete it’s very easy to expand the system in the future. It is now becoming common practice for IP Video systems to be used to expand existing analog CCTV systems based on cost alone – it’s often just too costly to cable in new cameras from remote locations. IP Video allows potential end users to easily trial the system at first-hand without commitment to large scale change from day one. Even though IP Video is an established technology, users will always want to convert to new technology at their own pace. The integration with intruder alarm and access control systems is also providing advantages as they are now moving to IP networks as well. These systems are also seeing the benefits and flexibility of replacing cable with a network. The CCTV video and data from these systems can share the network without any problems, in fact this level of integration provides some interesting features. For example, a security alarm can provide an input to the IP Video system, which automatically moves a camera to cover the incident and displays the video feed on a monitor in the control room together with a map of the location providing multiple perspectives on the incident. Digital Video Recording – the NVR It is important to differentiate between Digital Video Recorders (DVRs) and Networked Video recorders (NVRs), as both are often termed ‘digital’. A DVR digitally compresses analog video feeds and stores them on a hard-drive, the term ‘digital’ referring to the compression and storage technology, not the transmitted video images. The DVR therefore has to be located near the analog feeds. In contrast an NVR stores digital images directly from the IP Network. Therefore the most obvious difference between the DVR and NVR is that the DVR records analog streams from analog cameras, whereas the NVR records video streams that have already been encoded at the cameras. Thus you find no video connectors anywhere on a NVR; its inputs and outputs are IP data, comprising of compressed and encoded video. NVRs can be either PC software based or dedicated stand-alone units. The huge advantage of an architecture based on NVRs is that they can be located anywhere on a network – at the monitoring centre, adjacent to camera clusters, on the edge of a network or collected together in a hardened environment. In use their location is transparent to an operator; the recorded video stream from any camera can be viewed by any operator at any point on the network. NVRs record and replay simultaneously and recordings on any one machine can be remotely viewed by a number of authorized operators spread across the network simultaneously, all totally independently and without affecting each other. The independence of physical location is an important factor. By calculating the required network traffic and strategically placing NVRs accordingly, the impact of video streaming on bandwidth usage can be minimized. Typically an NVR might be placed near (in network terms, not necessarily physically) a camera cluster so that the load is carried by the local LAN capable of absorbing it easily, thus saving capacity on other, perhaps more restricted, parts of the network. “Mirroring” techniques are now often used to duplicate the recording of video streams on additional NVRs located at different parts of the network, which provides a high level of protection against network

failure; if one part goes down the other is there as a backup. You can have as many NVRs across a system as you like - there is no requirement for additional video cabling. Evidence from the NVR can be exported in the standard MPEG-4 format allowing it to be viewed by any 3rd party viewer such as QuickTime or Windows Media Player. However, the exported video includes encryption and watermarking to allow extremely secure detection of tampering such as frame removal, reordering or modification. Advanced Analytics – The Future Analytics is the processing of video images to detect such events as congestion, stolen objects, cars parked too long outside a building, people moving the wrong way through security checkpoints, etc. Analytics are available as an add-on to analog systems which makes it difficult to realise the true benefits of this technology. In IP systems however, analytics can be completely integrated so their full benefits can be realized. IP-based analytics can be run in two modes: real time within the IP transmitter/receiver at the camera, and post-processing, on any operator’s PC. The real time mode allows the system to automatically identify events as they occur. Post processing allows operators to run many different scenarios on recorded video, e.g. look for cars parked for more than 2 minutes. These two modes offer the best of both worlds, using analytics to identify events as they occur, and also providing advanced search tools for operators to analyze previous situations. Human operators are particularly poor at watching video monitors for long periods of time, but are generally very good at confirming whether something is an incident or not, once it has been flagged automatically by the system. Many of the latest developments in IP Video are centered on these types of features; here are just some of the analytics algorithms that are appearing on the market:

• Congestion Detection - too many people in too small a space • Motion Detection - person or vehicle moving, say, from left to right across a scene • Abandoned Object Detection - suitcase abandoned in an airport terminal • Counter Flow - person moving against an immigration route • Virtual Tripwire - detection and alarm upon breach of a defined line • Shape-Based Detection – e.g. vehicle detection • Object Tracking and Theft Detection - object removed from a busy scene

Advanced analytics is one of the outstanding applications of IP Video that simply cannot be matched by traditional analog CCTV systems and offers so many advantages that this feature alone can often justify the IP solution. It can be expected that huge productivity improvements will result from using analytics software during the searching of recorded material in post-event analysis - and for this, the NVR is the key.

About the Author Oliver Vellacott founded IndigoVision in 1994. He was previously a product manager with a background in intelligent camera products. Oliver studied piano at the Guildhall School of Music before gaining his first degree in Software Engineering from Imperial College London and then a PhD in Electrical Engineering from Edinburgh University. Dr Oliver Vellacott, CEO, IndigoVision Group plc, The Edinburgh Technopole, Bush Loan Edinburgh EH26 0PJ Tel: 0131 475 7200 Fax: 0131 475 7201 www.indigovision.com