Being Bandwidth Conscience with you Surveillance System

As the security industry transitions toward more IP friendly products, bandwidth constraints may be an issue. SourceSecurity.com's latest news article shares what you need to know about Estimating Bandwidth Requirements for Modern Surveillance Systems.

Most surveillance systems today transmit data over IP networks. As manufacturers continue to improve the capabilities of CCTV systems, the amount of traffic travelling on a network becomes increasingly large. Bandwidth is a key consideration in managing surveillance systems and ensuring their full potential is reached. In this article, Bosch discusses the importance of bandwidth and how to estimate the amount of bandwidth needed for a particular CCTV system.

What is bandwidth and why is it important?

Modern-day CCTV systems increasingly use IP networks to send video from one point to another (for example, from a camera to a Video Management System typically running on a PC).

IP networks are an attractive medium for transporting video because one cable can carry the video from many cameras. These networks also serve a multi-functional purpose because the same cable can carry video as well as two-way audio, alarm signals, relay signals, PTZ commands, and serial data. With Power over Ethernet, the cable can even carry power to the camera. This greatly simplifies the multitude of cables usually required.

However, the network is limited by the amount of traffic it can carry - known as bandwidth, which is measured in bits per second (bps). The table below shows the three kinds of star-topology Ethernet networks in common use today.

Name	Also known as	Bandwidth
10Base-T	Standard Ethernet	10 Mbps (Megabits per second)
100Base-T	Fast Ethernet	100 Mbps
1000Base-T	Gigabit Ethernet	1,000 Mbps or 1 Gbps

Video over IP consumes a large amount of bandwidth. As a rough guide, one camera might consume between 100 kbps and 2 Mbps - compare this to audio, which typically consumes only 80 kbps. This explains the immediate success of Voice over IP. The factors that affect bandwidth consumption are described in the table below.

Factor	Description	Examples
Video compression method	Typically temporal or spatial compression	MPEG-4, M-JPEG, Wavelet, and MPEG-2
Frame rate	Images per second	1-30 IPS
Image resolution	The number of horizontal and vertical pixels	QCIF, CIF, 2CIF, 4CIF (also known as full D1)
Scene activity level	The amount of activity in the camera's field of view	Low, medium, and high
Quiet time	The fraction of time where there is no movement (important for temporal compression algorithms like MPEG-4 because neglibible bandwidth is consumed during quiet time)	8:00 pm - 6:00 am Monday - Friday, all day Saturday and Sunday, equates to about 50% quiet time

If you run out of bandwidth on your network, you will start to experience the following:

• Video artefacts (e.g., blocks in MPEG and M-JPEG, and increased fuzziness in Wavelet)
• Frames may get dropped, making the video appear choppy
• The video resolution may drop from 4CIF to 2 CIF or even CIF, making the picture less clear
• The video may freeze entirely and lose the connection temporarily

What is the relationship between bandwidth and disk storage?

A single IP network cable can carry video from many surveillance cameras and also carry out multiple functions

They are directly related. If video is being transmitted at a certain bit-rate across a network to be stored, then it will consume disk space at exactly the same rate. For example, a 1 Mbps video stream will use 1 Mb (Megabit) of space in one second, or about 1/8 = 0.125 Megabytes per second, which equates to 0.125 x 3,600 = 450 Megabytes per hour (about 11 GB per day or 75 GB per week).

How do I know how much bandwidth I need?

This is an excellent question, particularly because it is unanswerable with any certainty. As explained earlier, it depends on so many factors that you can really only estimate your bandwidth and/or rate of disk-space consumption. This initial guess is based on your experience with previous projects and it is useful - but the best way to predict your needs is to run the actual test.

For example, consider planning an IP-based CCTV system for a school. How much bandwidth will the network need to carry for approximately 16 cameras, and how much disk space is required for seven days of recording?

View larger image Graph showing results gained by capping the bit rate

Capping the bit rate

You can ‘cap' the bit rate of each IP camera or encoder so that it never uses more than that specified amount. Note that when capped, the actual bit-rate at any particular moment may be well below the ‘cap' limit.

Advantage: Once you know the available disk space, you are guaranteed to get a predictable number of days of video. This is especially important for regulated environments. It is also good news for IT departments who want to know how much you are going to stress the network.

Disadvantage: To not exceed the allowed bit rate, the IP camera or encoder has to do something if it finds itself over-stretched. Normally it has the option to either drop some of the frames or reduce the video resolution of the frames - but this can be an issue when the video quality you need has to be degraded under any circumstances.

Unlimited bit rate

View larger image Graph showing the results of unlimited bit rate

You can let the IP camera or encoder help itself to whatever bandwidth it needs.

Advantage: Image quality never deteriorates.

Disadvantage: Under certain conditions, the peak load on the IP network may cause problems. This "help yourself" policy also may allow disk space to be consumed faster than you anticipated, so you may not have as many days of video as you expected.

Summary

With conventional VCRs, it is easy to predict the amount of disk space required for a specified number of days of recording time. With DVRs and IP-based CCTV, it can also be easy to predict (by capping) - as long as you are comfortable with the possibility that the video quality may degrade under certain circumstances. If you overestimate your bit rates, you will end up paying for more storage than you need.

The best way to predict your real needs is to pilot a small IP surveillance system (perhaps just one camera). Run it for a short while, then review the video and make any necessary adjustments. This is the most reliable way to get what you need and plan your infrastructure accordingly.

In addition to better estimating, it is also important to remember the enormous value of Recording at the Edge, which keeps video off the network for recording. In such a scenario, the network is only used for live streaming and playback.

View the Bandwidth quick reference guide

Metadata and Your IP Camera Surveillance Solution

With the advent of IP Cameras, CCTV technology is slowly phasing its way out of the Surveillance industry. But one feature some people are unaware of when it comes to switching their old Analog cameras to IP futureproof technology is the metadata that can be collected and used to trigger certain functions.

The following article from Sony's Product Manager Yu Kitamura offers some great insight on this subject.

Yu Kitamura, Product Manager Network Video Monitoring Sony

Metadata in IP video surveillance and monitoring: operational benefits and cost savings
SourceSecurity.com

Metadata saves on resources required to store large amounts of data

Yu Kitamura, Product Manager, Network Video Monitoring, Sony Europe explains the facts about metadata, and their benefits.

All organisations have to face the costly challenge of the storage and management of their valuable data. In the sphere of security, where visual data is indispensable, any avenues that make the capture, storage and retrieval of that information more efficient will command budget attention.

One of the inevitable costs of a comprehensive security operation is the money and resources required to store weeks of largely irrelevant security film, and also to identify and retrieve the relevant material from the archives when needed. What can make metadata- - or data about data - economically attractive is being able to save on those resources.

Key facts about metadata

Metadata may sound like yet another stream to manage but, on the contrary, it is actually the key to automating management, and allowing technology to make some decisions by itself. With current network video monitoring solutions

On a more strategic level, the use of metadata also has an important role to play in keeping traffic off the network

available , as well as the data that a security camera usually captures, the additional metadata enables the surveillance system itself to do much of the detection work that normally falls on the security operative. It can, for instance, pinpoint with coloured boxes areas of the screen that contain threats, making the job of the observer easier, and the ultimate response quicker and more effective.

On a more strategic level, the use of metadata also has an important role to play in keeping traffic off the network - an advantage that not only comes with substantial operational benefits, but also one that has significant cost implications.

New security cameras which make use of metadata can independently recognise visual security breaches, such as abandoned packages or suspicious movement, and are sophisticated enough to know the difference between moving people and safe background conditions, such as blowing trees or splashing fountains. Such a capability means that those areas need no longer form a security blind spot as they do with current analogue CCTV.

As a consequence, there is no more need to ‘mask' problem areas within the field of view. These cameras' capabilities also enable many of the common time-consuming false alarm scenarios to be eradicated. Once again, this is a function of the metadata, which feeds back information on the risks associated with what the cameras are seeing.

The benefits of metadata technology

The metadata technology of these security cameras comes with technical benefits too. Bandwidth requirements are minimised

Metadata technology provides fast and accurate results when searching through historical data

because only legitimate threat images and data are sent and stored. In a security environment where monitoring may be happening 24/7, the screening out of irrelevant data is a big step forward. It makes a significant difference to the cost and management of the captured material, and it also makes for fast and accurate results when searching through historical data.

Application of intelligence in video surveillance and proactive detection

Surveillance software currently available in the market analyses, assesses and responds to the images transmitted by intelligent security cameras. The surveillance software packages also gain additional information about the images from the cameras' metadata. By then employing features that alert and direct operatives to the visible threats within a frame of video, this type of software provides more than just a safety net - it delivers proactive detection.

This type of security software is designed with the practicalities of security work in mind. An unmistakable on-screen highlight box locates a threat, captures the observer's attention and leaves no room for error. It enhances the security decision-making process and provides accurate back-up data in time-critical situations, delivering essential decision support when it is most needed.

Metadata...it is actually the key to automating management, and allowing technology to make some decisions by itself

What allows this type of system to run so efficiently, with the metadata running alongside the video and audio data is its development of Distributed Enhanced Processing Architecture (DEPA). Having intelligent cameras on the same network as the servers that are running the security software opens up enormous possibilities and potential, and now means that a multi-camera security set-up doesn't have to be complex and difficult to monitor; personnel can be guided by the software to the hot-spots and the right screens to watch. They can be shown the detail of the threat before it becomes an incident, and may even as a result prevent it from turning into an incident at all.

A new era in security network video monitoring is underway. The return on investment from bringing monitoring cameras on to the network and away from the world of analogue CCTV, are clear. It is no longer necessary to run, manage and upgrade two separate systems. The same investment that allows a company to save money on voice over-IP can now benefit the security function as well. Use of the network also allows the possibility of additional hardware devices to function alongside the network video monitoring, allowing features such as triggered lighting or door locking.

IFSEC 2010 Cameras To Look For!

IFSEC2010 is soon approaching and there are several new products to look out for if you are attending. HD IP Camera Technology is proving itself as the future in network surveillance camera solutions and beyond. Its crystal clear imaging can be used in almost any industry, and prove useful especially for web marketing for live HD video viewing of resorts, construction sites, and beaches, as seen by HDRelay.com. The latest in HD IP camera technology is also future proof, providing usage for many years to come.

Here are some of the latest in HD IP Camera Technology coming from Sony Security and Axis Communications that will featured at this year's IFSEC, May 10 - 13 in Birmingham, UK

Axis Communications -- Booth 4E90

The Axis Q6034 is the latest PTZ HD IP Camera to be released by Axis. It boasts several features, including:

• HDTV 720p, day/night and H.264
• 18x zoom and fast pan/tilt
• High Power over Ethernet (IEEE 802.3at)
• Two-way audio* and audio detection
• Four configurable inputs/outputs* for connection to external devices such as sensors and relays
• Local storage with a built-in SD/SDHC memory card slot
• Day and night functionality, progressive scan, 128x wide dynamic range, electronic image stabilization, and E-flip

"AXIS Q6034 combines high-speed and robust pan/tilt capability with HDTV-quality video to provide exceptional coverage of large areas and great detail when zooming in on an object," says Erik Frännlid, Axis' Director of Product Management. "AXIS Q6034 is easy to install and is powered using High Power over Ethernet. An outdoor-ready version is also planned for release later this year."

This camera will be on display at IFSEC and is coming in May2010 to WebCamProShop. Click here to learn more about this camera.

Sony Security -- Booth 4J10

Two new HD IP Cameras from Sony Security, SNC-DH180 and SNC-DH240 will be unveiled for the first time in Europe at this years IFSEC.

The SNC-DH180 is a Vandal Resistant HD Minidome Camera that encompasses Sony's popular View-DR (Visibility enhanced wide Dynamic Range) technology and and IR Illuminator, making it a cutting edge Outdoor-ready HD Surveillance Camera.

More features include:

• Superior 720p HD picture quality, supporting H.264 at 30 fps
• Maximum reoslution 1280 x 1024
• The new Exmor CMOS sensor achieves high image quality and high sensitivity
• Clearly see objects in the dark up to 15 m (49 feet) away with IR Illuminators
• The Visibility Enhancer optimizes contrast and makes the subject more visible, even in severe backlight or shadow conditions
• XDNR (eXcellent Dynamic Noise Reduction) technology for clear images without motion blur under low illumination
• Easy Focus function/Easy Zoom function
• Intelligent Motion Detection, Advanced Audio and Tamper Alarm
• Built-in heater
• IP66 Rating

The SNC- DH240 is also an HD Minidome which has similar features to the DH180 -- the main one being the maximum resolution of 1920 x 1440. Pretty impressive!

This model, however is not vandal proof. WebCamProShop suggests you protect you hardware investment by storing your HD technology in a Dotworkz D2 or D3 Housing. These rugged enclosures are made to withstand any weather condition or extreme temperatures. Learn more about Dotworkz Products on their website, Dotworkz.com. All products are also for sale on WebCamProShop. Click here for more information. These Sony products will also be available soon!