In this white paper Tim Cocks of distributor CCTV Center explains the reality behind 20 of today’s most common IP CCTV myths.
Introduction
There is now no question that IP network-based CCTV systems have proved their reliability – and their operational advantages – in installation after installation. There is now also widespread agreement that the future of CCTV will be IP-based. As high profile, successful installations show what can be achieved with IP, the balance of the market is steadily tipping away from traditional, analogue solutions.
However, some of the old myths about the supposed limitations of IP die hard. While there originally may have been truth in some of them, the facts on the ground have changed. In this white paper we will blow open some of these myths. We will explain the old misconceptions surrounding IP and, most importantly, look at the technology as it really is today.
Among our 20 key points we will explain the facts about:
? Image quality
? Bandwidth & transmission
? Reliability
? Security
? Price & Scaleability
? Plus more, including IP’s simpler installation and maintenance features
The most important fact of all is that whatever your role in the industry – whether you are an installer, buyer or system designer – gaining a full understanding of IP means you will be better equipped to take advantage of the more flexible, secure and affordable future that this technology offers. By Tim Cocks, Technical Director, CCTV Center.
Myth number 1
‘IP CCTV systems only produce poor quality images’
The reality
Today’s truth is that properly designed IP surveillance systems will produce images which are every bit as sharp and clear as older, analogue set-ups.
Good quality IP cameras (or network cameras) have exactly the same high quality image sensors and optics as analogue cameras. Of course these high quality, professional products should not be confused with lower-spec models, or with PC webcams which cannot deliver the same results. The more demanding the conditions, the bigger the performance gap will be between the professional IP cameras and the cheaper models – so it’s important to chose the right camera.
IP systems allow you to take full advantage of mega-pixel technology, whereas analogue systems do not. Analogue cameras are in fact limited to 0.4 mega-pixel resolution because of the PAL standard that they operate on. By contrast, mega-pixel network cameras can deliver 1.3 mega-pixel images or more.
Image quality degrades less with digital systems. With all analogue systems the CCTV images have to be converted between analogue and digital formats, typically three or four times (for transmission via coaxial cable; for compression and processing; for display on the monitor etc). Each time this happens the image quality degrades. By contrast, when IP-based digital signals are transmitted directly via the network to a Network Video Recorder (NVR) and digital LCD monitor they do not have to be converted at all, so there is no loss of quality. Not surprisingly, this can result in vastly superior images.
Myth number 2
‘IP CCTV uses up all my bandwidth’
The reality
High quality transmission of data for several CCTV cameras can be comfortably handled by typical office networks. Where more cameras are needed, it’s easy to establish separate networks. Today there are easy and affordable data-carrying solutions for all IP surveilance applications.
A typical single network camera will have a video feed ranging from 0.2 to 2.0 Mbps, depending on compression, image size and frame rate. Therefore, a typical office network of 100 Mbit will be able to easily cope with the transmission demands of several cameras.
As soon as you have more than a few cameras, put in a separate camera network. It’s easy to separate networks with readily available network switches and routers. Existing structured cable, where available, can be used, but all the cameras should feed into Layer 2 Managed Switches. For enterprise solutions using large numbers of cameras, an Ethernet backbone is recommended.
When setting up a network it’s important to ensure that it has enough capacity to cope with the worst-case-scenario – that is, plan for the maximum demand occasions, when all cameras are recording.
There are some useful techniques that installers can use to allow CCTV to be integrated into an organization’s network without overloading it. For example, with ‘schedule recording’ users can chose not to have all cameras recording all of the time. This means that less data will need to be transferred.
Technical considerations – in brief
The amount of bandwidth that a camera uses is determined by the image quality and frame rate set for the camera, and the compression algorithm used. The compression technology is pre-determined by the camera manufacturer but good quality cameras will allow the image quality and the number of images per second to be set for each camera. For corporate security applications, cameras with M-PEG4 compression set to high image quality and 12-15 ips give good quality images in almost real-time with fluid movement and without using excessive bandwidth. Cameras set this way will use approximately 1.5Mbps of bandwidth.
For high security and specialist applications we recommend that a bandwidth calculator is used. These should be available from all good manufacturers.
Although most network cameras currently use a 10 Base-T/100 Base-TX Network Interface, and consequently only require a 100Mbit network, we recommend the use Gigabit (1000 Mbit) Network Switches for professional systems. The price of Gigabit switches is now low enough for them to be the network switch of choice to both ensure the free flow of data over the camera network, and enable future system expansion.
Myth number 3
‘IP CCTV systems are unreliable’
The reality
In fact modern networks are extremely reliable.
Modern networks can include multiple IP routes connecting to the network switches. This provides back-up paths in the event of a failure of either equipment or a cable. So it is possible to build a network that can continue working even in extreme conditions – in fact, much more so than with analogue.
A more proactive approach to system management is possible with IP-based systems. For example, environmental monitoring devices can warn users if there are problems on site (flood, fire, temperature rise etc), meaning that systems can be better protected from damage and down-time. Similarly, the overall health and performance of the network can be continually monitored, making IP more reliable than older un-checked analogue systems.
By their nature, networked systems feature more built-in redundancy and resilience than the older, less flexible analogue set-ups. It’s also worth remembering that proprietory operating systems are less vulnerable to attack by hackers and virus writers, unlike PC-based systems that require regular patching for security vulnerabilities.
IP-based NVR recording offers key benefits over PC-based solutions: with purpose built hardware it is reliable, scaleable, easy-to-use and can be located anywhere on the network. IP CCTV can either be recorded onto a PC with video recording software or a Network Video Recorder (NVR). Where necessary, analogue cameras can also be recorded onto a Digital Video Recorder (DVR) connected to the network. NVRs are more network efficient than DVRs and offer better image quality, a requisite of any CCTV system.
Myth number 4
‘IP CCTV systems have slow transmission’
The reality
Dedicated camera networks can easily cope and deliver excellent video streaming. Wireless networks are a bit slower but are delivering increasingly useful results where cable can’t be used. Currently broadband internet viewing is limited to a few frames per second, but upload speeds will certainly continue to increase.
In IP CCTV, bandwidth refers to the data transmission rate of a signal, measured in bits per sec.Local Area Networks typically have speeds of 100Mbps (Fast Networks) or 1000Mbps (Gigabit Networks). This means that dedicated camera networks, particularly those using an Ethernet backbone will easily cope with multiple camera locations each streaming less than 2Mbps.
Wi-Fi Networks have maximum data speeds of 11Mbps (802.11b) or 54Mbps (802.11g). Wireless can be very useful where cable cannot be easily or cost-effectively installed, but specialist help should be sought for multi-camera links.
Broadband Internet download speeds typically range from 1Mbps to 20Mbps. Upload is different, and maximum ADSL upload speed where data is sent from a local system (e.g. CCTV system) to a remote system (eg remote viewing PC) is 512Kbps. With SDSL broadband, upload and download speeds are the same and are typically up to 2Mbps.
ADSL broadband is useful for remote viewing of images, but as can be seen from the above figures upload speeds are limited to only a few frames per second. Until ADSL upload speeds are improved, the only ways to increase remote viewing speeds is to bond multiple ADSL lines together, subscribe to an SDSL line (where available) or subscribe to a leased line.
Myth number 5
‘IP CCTV systems have high storage costs’
The reality
Storage costs are now very affordable and are decreasing all the time, with HDD storage relatively inexpensive and NVRs allowing flexible, tailored recording schedules.
IP CCTV systems store video recordings on Hard Disk Drives (HDDs). HDDs were originally developed for use in the computer industry, and the cost per Gigabyte of storage continues to go down year on year. This trend is almost certain to continue, irrespective of whether the hard disk is contained within a PC, Network Video Recorder or other storage device.
Although Hard Disk Drive Storage costs continue to go down, it is worth having an archiving plan to ensure that vital information is retained, whilst unwanted information is neither recorded nor retained. A RAID5 system can be used to provide essential back-up in case of HDD failure. This is especially useful as we move to larger and larger drives (1Tbyte) and beyond, as fewer drives are used in the system. It’s possible to implement RAID5 by adding one extra drive.
Modern NVRs can record to a schedule, against an alarm trigger or against Video Motion Detection (VMD), and the recording quality and frame rate set accordingly. Many modern security systems for corporate applications record high quality images in real time against VMD during the day, and high quality images at 13 images per second (ips) continually out of operating hours.
As HDD storage is relatively inexpensive, the main criteria should be to ensure that the storage is reliable. Many industry pundits consider that purpose-built professional Network Video Recorders and expansion bays offer the most reliable hardware for IP CCTV system image storage.
Myth number 6
‘Real time recording can’t be achieved with IP’
The reality
With IP we can chose exactly what sort of ‘real time’ recording we want, tailoring the system to the application.
What do we mean by real time recording? According to the theory of persistence of vision, the human eye retains an image for a brief moment. When a series of still video images is displayed in quick succession we get an illusion of movement (that is, we do not see the individual frames in the series).
When is real time recording important?
It is considered vital in high security applications and also when monitoring financial transactions. Any process where it is critical not to miss any information, such as at a casino gaming table should also use real time recording. For most general security and surveillance applications however, 24 hour real time recording is not required, and generally means massive amounts of irrelevant information are being needlessly recorded and archived. It is far better in these instances to record in real time against an alarm or Video Motion Detection.
It is essential that we don’t miss any critical information, but recording irrelevant and redundant information is a waste of money and clutters up systems. So how do we balance the two? We recommend that for high security and high speed transactions, video cameras are recorded at 25ips, and for general applications images are recorded at 6 or 12 ips, jumping to up to 25ips against alarm or activity.
Technical considerations – in brief
In the PAL television system used in Europe ‘real time’ video records at 25 frames per second. A technique called interlace uses persistence of vision to combine two consecutive images (or fields) to create one frame with higher detail in non-moving areas. Because the fields are exposed and displayed separately, a single TV ‘frame’ can potentially contain motion or even two distinct images, with ‘combi-artifacts’ being seen on a still image where a recording system has combined the two fields. Modern IP cameras now use non-interlaced or progressive scanning for transmitting moving images in which all the lines of each frame are drawn in sequence. Real time recording however is still considered to be 25 ips.
Myth number 7
‘Remote monitoring of IP CCTV is not possible’
The reality
IP systems are designed to allow both active monitoring and passive viewing. In fact IP is making remote surveillance more feasible for all levels of application.
Remote monitoring is different from remote viewing. Remote viewing is the observation of live and recorded images on a PC, usually over the internet, and usually through the PC browser. Some devices may require FOC software downloaded on the PC for remote viewing. Open standard and proprietary software is also available for purchase with enhanced features and the facility to look at multiple remote devices on the same screen.
With IP so many more things are possible. Although upload speeds are still limited over the internet, the ability to view images remotely is a fantastic facility made possible by IP. It allows business owners to check the security of their premises remotely, and allows business managers to confirm that remote branches are operating as they should without the need to continually travel in person.
Remote monitoring is done at a remote central station using specialist software by companies geared up to both receive images against an alarm, and to respond accordingly. Images are generally uploaded to the monitoring station against an alarm that an operator can review and record and then act on by contacting the police, a private security company or the business owner as appropriate.
Because the monitoring station is continually monitoring its remote sites, it is often the first place where CCTV system faults are spotted, for example if a camera is down and not transmitting images. Also with advent of IP it is possible to check camera and recorder settings, and perform fixes and upgrades remotely. Is this respect partnering a forward thinking monitoring station can not only allow your CCTV system to be monitored cost effectively, but can also help with the maintenance of the system.
Myth number 8
‘IP CCTV systems are not secure’
The reality
With all their data encrypted, secure IP networks are more robustly protected than analogue systems ever were.
It is important to ensure that the correct security measures are in place. So long the right protection is used (including firewalls, VPNs and password protection) the Internet can safely transfer all kinds of sensitive information. Any system is only as strong as its weakest link so anyone using a public network for video transmission should secure their data traffic using VPN technology.
Banks and financial institutions have paved the way in using the Internet as a medium for global money transactions, helping it to develop as a proven medium for other secure applications including IP CCTV.
Analogue surveillance systems are less secure than the new digital technology, because they have have no encryption or authentication of information. It is very easy for third parties to tap into the cables of an analogue system and gain access to supposedly secure video transmissions. This cannot be done with secure IP networks.
Myth number 9
‘I will get data loss if an IP product fails’
The reality
Network-based systems can offer greater protection against failure than old analogue technology, so long as systems are built using reliable components from reputable manufacturers.
The essential facts
Analogue systems can go down too if a camera, recorder or other key component fails. The way to minimise this risk is to choose reliable equipment from a leading brand, and to consider some duplication of equipment in critical positions. IP CCTV systems are no different and the same principles apply. IP systems are more readily viewed in multiple locations including remotely, and consequently any equipment failures may be more easily spotted.
It is important to use reliable network components. Those with experience of home PC networks will know how ‘flaky’ some domestic equipment, particularly wireless equipment, can be, often needing a re-boot to come back into operation. In most domestic situations this can be frustrating but not critical. Security systems are of course a different matter, and care should be taken to choose professional, ruggedised equipment, particularly for sensitive applications. In short, the equipment should be selected for the environment – for example, use field-hardened products for non air-conditioned areas.
IP also has some other tricks up its sleeve including network cameras with the capability of recording a loop of back-up information to an SD card or similar removeable media. This means that if there is a temporary problem at the recorder, backup information is also recorded at the camera.
Myth number 10
‘There is no complete IP CCTV system available’
The reality
The market has developed rapidly, with manufacturers racing to develop the best IP CCTV equipment. All the hardware and software you need is now available.
Facts
Over recent years a number of system gaps have been identified. PTZ cameras, particularly for external use have not been readily available, and the control of PTZ cameras by joystick controller has not been possible. Transmission distances have been limited to the 100m achievable over Cat 5 cable, and video matrices with multiple monitor outputs have not been available. However, as IP systems develop at a frantic pace, all these limitations are being overcome.
Excellent PTZ cameras for internal use are available now, and fully functional cameras for external use are being launched at all the main CCTV shows. Video Servers can also be used to provide high quality IP images from good existing analogue PTZ cameras.
The leading manufacturers now offer joystick control of their PTZ cameras, where the joystick is connected to the network like all other devices.
Fibre is leading the way in extending transmission distances, and because optical fibre is electrically transparent, fibre optic transmission can be used even in the vicinity of heavy electrical plant. This means that Ethernet signals sent over fibre can be used where traditional coaxial cables could not, both as a means of extending transmission distances, and as a means of overcoming electromagnetic interference. Video and data can be sent up to 4km using multimode equipment, and 30km plus using single mode equipment!
Good software enhances IP systems, and well priced software is now available to view live and recorded images from multiple devices. Advanced features such as mapping allow camera locations to be easily seen, and the images from those locations quickly brought to screen by clicking on the camera item on the map.
