What the Difference between IP Cameras and CCTV Cameras ?

Many have speculated that the area of CCTV (closed-circuit television) cameras is coming to an end. These multi-purpose video cassette recorders and all their T-160 tapes are quickly being replaced by capture cards, embedded processors, codec, and more advanced devices. IP cameras have played a major role in phasing out CCTV cameras, as they offer many of the same benefits, yet provide much more. What’s the difference? Plenty! Let’s delve into some of the details and find out how IP cameras tower over their analog CCTV counterparts.

Remote Viewing

The major benefit of IP cameras is the luxury to view live video via the internet from any location in the world. While CCTV cameras can enable viewing over the internet, they require additional software and hardware components to function properly. An IP camera is integrated with all the necessary tools and doesn’t require any additional installations. Some of the newer models are even able to view live video on a cell phone or other mobile device over a 3G network.

Remote Recording

The primary function of a surveillance camera is to monitor a certain area when security and staff are unable to do so. While it serves its purpose for the most part, CCTV cameras are susceptible to security breaches, and the tapes they contain can be stolen. IP cameras enable recording to remote locations, which virtually eliminates such a scenario. Even if security is breached, the intruder will not be able to steal the tape or recording device because it is physically stationed at a remote location.

Wireless Capability

Because IP cameras leverage standard IP (Internet Protocol) networks, many of them are available in wireless variations to provide the ultimate in portability. All the device requires is a single cable for a power supply, which results in less work when installing the camera in the recording location.

Video Analytic

More IP cameras are being implemented with video analytics to provide advanced tracking and motion detection capability. This technology is so sophisticated that it has the ability to distinguish between the movement of a person, a car driving down the road, or a tree merely swaying in the wind.

More Advancements to Come

CCTV cameras aren’t completely obsolete, but are light-years behind in comparison to IP cameras. IP technology allows individuals and businesses to effectively monitor their home or office premises with little to no security risks. Evolving rapidly, it’s almost certain that you will be able to do much more with an IP camera in the very near future.

What is IP camera ?

Network IP Cameras have been around for at over a decade now. Only recently have cabling installers began to pay attention to the technology because surveillance cameras have traditionally run on separate coaxial cable. Around 10 years ago, the first digital IP camera connected directly to a data network which changed the future of the surveillance camera industry.

During the early stages, the technology was not as professional as analog cameras. Most cameras were seen as ‘web cameras’, which were used to view objects or events over the internet or a LAN.

Today IP network cameras meet the same requirements and specifications as analog counterparts and in many areas surpass analog camera performance and features . Forecasts show that the network IP camera market share is growing at a much faster rate than its analog competitor and has surpassed the analog camera in market share.

An IP Camera is a networked digital video camera that transmits data over a Fast Ethernet link. IP Cameras (also called “network cameras”) are most often used for IP surveillance, a digitized and networked version of closed-circuit television (CCTV).

Benefits of IP camera over analog technology include:

• Remote administration from any location.
• Digital zoom.
• The ability to easily send images and video anywhere with an Internet connection.
• Progressive scanning, which enables better quality images extracted from the video, especially for moving targets.
• Adjustable frame rates and resolution to meet specific needs.
• Two-way communication.
• The ability to send alerts if suspicious activity is detected.
• Lower cabling requirements.
• Support for intelligent video.

Disadvantages of IP surveillance include greater complexity and bandwidth demands. One alternative for organizations with substantial investment in analog technology is to use a video server to, in effect, turn analog CCTV cameras to IP cameras. A video server is a small standalone server that converts analog signals to a digital format and provides the analog cameras with IP addresses.

Nevertheless, because it offers much more sophisticated capabilities, IP surveillance is increasingly replacing analog CCTV. An industry report from International Data Corporation (IDC) predicts that shipments of IP cameras and related products will increase 75% between 2012 and 2015.

IP CCTV transmission methods

There are essentially three ways of transmitting video streams over the network from the source to the destination: broadcast, unicast and multicast.

Broadcast
Broadcast is defined as a one-to-all communication between the source and the destinations. In IP video surveillance, the source refers usually to the IP camera and the destination refers to the monitoring station or the recording server. In this case, broadcasting would mean that the IP camera would send the video stream to all monitoring stations and recording servers, but also to any IP devices on the network, even though only a few specific destination sources had actually requested the stream. Typically, this method of transmission is not commonly used in IP video surveillance applications, but can be seen more often in the TV broadcasting industry where TV signals are switched at the destination level.

Unicast
Unicast is defined as a one-to-one communication between the source and the destination. Unicast transmissions are usually done in TCP or UDP and require a direct connection between the source and the destination. In this scenario, the IP camera (source) needs to have the capabilities to accept many concurrent connections when many destinations want to view or record that same video at the same time.
In terms of video streaming in unicast transmission, the IP camera will stream as many copies of the video feed requested by the destinations. In figure 1 below, three copies of the same video stream are sent over the network; one copy for each of the three destinations requesting the stream. If each video stream is 4 Mbps, this transmission will produce 12 Mbps (3x4Mbps) of data on multiple network segments.

As a result, many destinations connected in unicast to a video source can result in high network traffic. In other words, if we imagine a large system with 200 destinations requesting the same video stream, we would end up having 800 Mbps (200x4Mbps) of data travelling over the network, which is realistically unmanageable. Although this method of transmission is widely used over the Internet where most routers are not multicast-enabled, within a corporate LAN, unicast transmission is not necessarily the best practice as it can quickly increase the bandwidth needed for viewing and recording camera streams.

Multicast
In multicast transmission, there is no direct connection between the source and the destinations. The connection to the video stream of the IP camera is done by joining a multicast group, which in simple terms means actually connecting to the multicast IP address of the video stream. So the IP camera only sends a single copy of the video stream to its designated IP address and the destination simply connects to the stream available over the network with no additional overhead on the source. In other words, the destinations share the same video stream. In figure 2 below, the same three destinations requesting the video stream have the same impact on the network as a single destination requesting the stream in unicast and there is no more than 4 Mbps of data travelling on each segment of the network. Even with 200 destinations requesting that video stream, the same amount of data would be travelling on the network.

It is evident at this point that using multicast transmissions in an IP video surveillance application can save a lot of bandwidth, especially in large scale deployments where the number of destinations can grow very quickly.

Bandwidth optimisation for IP CCTV
When it comes to IP video surveillance, it is important to efficiently manage the way video streams are transmitted over the network in order not to overload the available bandwidth. Even though IT infrastructures are built to handle any kind of data, the applications generating traffic over the IP network need to be conducive with the efficient utilization of the network resources in place. To this end, different functionalities and mechanisms are offered by IP video surveillance solution providers to allow optimization of bandwidth and network resources such as:
• Multicasting
• Multistreaming
• Video compression

Even though the capacity and speed of the network are constantly increasing and its associated costs are declining, this is still not a good reason for users to ignore the additional investments and efforts needed to optimise bandwidth management. The amount of data travelling on the network is also still on the rise and therefore, investments in bandwidth optimization are ones that can contribute to a reduction in total cost of ownership, specifically in respect to efficiency gains and maximized resources.

For example, in video surveillance, more and more end-users are requesting cameras with higher picture quality and resolution, often opting for high-definition and megapixel cameras. These types of cameras require much more bandwidth than standard definition cameras. Also, more and more people inside as well as outside an organization’s walls are requesting access to video streams over the network. In the case where a large number of users are simultaneously trying to access a specific video stream, efficient use of network resources can be crucial in avoiding overloaded capacity and entire network crashes.
It is equally important to realize that optimizing the bandwidth on the network does not necessarily go hand in hand with large capital investments, but is more a matter of putting the right solutions in place and leveraging the unique and powerful capabilities of these solutions.

How does a Network Camera work ?

An IP Network Video Camera is a Video Camera with a built in web server that can be controlled, monitored and viewed from virtually any location via High-Speed Internet Access.


A Network Camera has its own IP Address and built-in computing functions to handle network communication. Everything required for viewing images over the Network is built into the unit. An IP Network Video Camera can be described as a Camera and a computer combined. It is connected directly to the Network as any other network device and it has built-in software for a Web server, FTP Server, FTP client and e-mail client. It also includes alarm input and relay output as well. More advanced Network Cameras can also be equipped with many other value-added functions such as motion detection and an Analog Video Output.

The Network Camera's camera component captures the image, which can be described as light of different wavelengths, and transforms it into electrical signals. These signals are then are converted from Analog to Digital Format and transferred into the computer function where the image is compressed and sent out over the network.

The lens of the Network Camera focuses the image onto the image sensor (CCD). Before reaching the image sensor, the images pass through the optical filter, which removes any infrared light so that the "correct" colors will be displayed. The image sensor converts the image, which is composed of light information, into electrical signals. These electrical, digital signals are now in a format that can be compressed and transferred over networks. The Camera functions to manage the exposure (light level ofimage), white balance (adjusts the color levels), image sharpness, andother aspects of image quality.
  A single camera setup

• The camera turns video & audio into data
• The camera connects to your Network or direct your Router and transmits this data onto the network
• This data can then be viewed as high quality images, and audio on any authorised PC, Mac or Mobile Phone; on the local network, or over the internet
• The Recording Software supplied can be used to record and view up 64 cameras on any compatible Windows PC or Laptop.

 To setup more than one camera

• Each camera turns video & audio into data
• The camera connects to your Network via a Network Switch and transmit their data onto the network
• This data can then be viewed as high quality images, and audio on any authorised PC, Mac or Mobile Phone; on the local network, or over the internet
• The Recording Software supplied can be used to record and view up 64 cameras on any compatible Windows PC or Laptop

 To setup multiple cameras over multiple sites

• In the example below each site has 2 IP cameras
• At site 1 the cameras are connected to the local network and recorded on a Laptop running the Xvision Recording Software
• The cameras are also connected to the Internet via the router
• At site 2 the cameras are connected to the Internet, no local recording or viewing is taking place
• At Head Office the cameras are being recorded and viewed live on a Laptop running the Xvision Recording Software
• The cameras can also be viewed from an iPhone (over 3G) by the Managing Director when he is out of the office.

IPCCTV Design - Network Requirements

Designing a IP CCTV 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 analyse 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.

Transmitter/receiver modules transmitMPEG-4 quality digital video, audio and control data over the IP network the typical NVR solution simply requiresa 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 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 is important to differentiate between Digital Video Recorders and network 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 authorised 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 minimised. 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 for 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 realised. 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 analyse 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:
1. Congestion Detection - too many people in too small a space
2. Motion Detection - person or vehicle moving, say, from left to right across a scene
3. Abandoned Object Detection - suitcase abandoned in an airport terminal
4. Counter Flow - person moving against an immigration route
5. Virtual Tripwire - detection and alarm upon breach of a defined line
6. Shape-Based Detection – e.g. vehicle detection
7. 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.


Sources:
http://www.gobeyondsecurity.com/forum/topics/designing-the-ip-cctv-system
http://www.gobeyondsecurity.com/forum/topics/what-is-a-dvr-what-is-a-nvr