CCTV Recording Resolution

Digital Video Recorders (DVR) and Network Video Recorders (NVR) are the heart of every security camera system. Customers often ask us about recording quality from CCTV cameras, things can seem relatively straightforward: you’ll need a DVR/NVR that can handle as many channels as you have cameras, and the more hard drive space you have for archiving all that video, the better. Naturally a customer wants to know how clear the video resolution will be from a system before making a purchase decision. Final outcome of your captured footage, 

Recording resolution is the number of pixels (dots) used to create an image. Higher resolutions use more pixels to create an image. This means that greater amounts of detail can be expressed in the image, but larger files sizes and a greater amount of storage (i.e. Hard drive space) are required to save the images or video. See the example below.

The resolution is increasing from left to right

Recording resolution is measured as the number of horizontal pixels by the number of vertical pixels (Width x Height). The following table shows some common recording resolutions.

Name	Width (Horizontal Pixels)	Height (Vertical Pixels)	Total Number of Pixels	Recommended Camera Equipment
CIF	360	240	86,400	320TVL, 400TVL, 420TVL, 480TVL,
2CIF	720	240	172,800	420TVL, 480TVL, 540TVL
VGA	640	480	307,200	540TVL, 600TVL, 1MP
D1	720	480	345,600	600TVL, 650TVL, 700TVL, 800TVL
720p	1,280	720	921,600	720p, 1.3MP
QVGA	1280	960	1228,800	960p, 1.3MP
1080p	1,920	1,080	2,073,600	1080p, 2.1MP
3MP	2048	1536	3145,728	3MP
5MP	2560	1920	4915,200	5MP
6MP	3032	2008	6088,256	6MP
8MP	3264	2448	7990,272	8MP

Notice the increase in the total number of pixels as the resolution increases. Because the total number of pixels is determined by the number of horizontal pixels times the number of vertical pixels, if both horizontal and vertical pixels are doubled, the total number of pixels increases by a factor of 4. This means that the amount of hard drive space needed to store an image or a given duration of video will also increase by a factor of 4 (given factors such as the frame rate remain equal). It is recommended to try different configurations on your system to balance image quality against the amount of storage space available.

Now based on the capabilities of your DVR you may choose to record in a certain picture resolution based on certain requirements unbeknownst to anyone but you.

I have seen a lot of misconceptions of the newly introduced 960H. Amongst the confusion, I have seen a statement along the lines of 960H provides you a 960x480 and/or 720x480 picture; as well that it improves the picture of any camera fitted with a 960H sensor via your current DVR. This is a BIG misconstrued myth. Submitted for your approval are the facts of 960H

1.   960H is NOT a megapixel resolution

2.   960H sizes are NOT 960x480 or 720 x 480 formats

3.   Cameras equipped with 960H alone, will NOT provide you with a refined captured footage of 960x480

The graphic below shows a comparison of the resolutions listed if each pixel takes up the same amount of space.

F.Y.I For all footage across every system, after video is recorded it can be magnified (zoomed in) but only digitally either through a computer or the DVR (if capable). That means, the individual pixels that create the picture can be made bigger. However, for analog footage, there will be no real advantage at detail due to the low-res of pixels.

Building Automation Protocol selecting

Building Automation Protocol selecting

Each of the competing protocols claims to be the best. So how do facility executives select the one that is best suited for the facility?

Data is communicated between devices through a Communication Protocol. It is the language that a particular device is able to interpret and forward to other devices on the network. Some common protocols are BACnet, Lon, and Modbus.

Protocols must be selected based on the needs of the facility and its ability to support a particular protocol. Each has been used many times to implement an interoperable system. Each has its advantages and disadvantages. Involve your information technology department. They generally are the controlling agency for the facility’s network infrastructure.

When selecting a control system choose one where the front end is compatible with a number of protocols. This will give greater flexibility as building equipment and devices change over time.

Why you want a BMS with open protocols

A BMS with proprietary protocols locks the system owner into using a single BMS vendor. For example, you can’t remotely change the set points of a proprietary BMS unless you use the vendor’s software.

In contrast, with open and standard BMS protocols you can shop for alternative providers of digital devices and enterprise software.

Building Automation Controls Network (BACnet): BACnet is a network protocol specifically used for multiple devices to communicate across building automation systems by system users and building system manufacturers

Modbus: Modbus is a network protocol best used for industrial automation systems specifically for connecting electronic equipment. Although Modbus is best for industrial applications, its simplicity allows it to be a useful tool for building automation as well.

LonWorks: LonWorks is a communication network protocol useful for building automation applications designed on a low bandwidth, for networking devices through power lines, fiber optics, and other media.

Protocol	BACnet	Modbus	LonWorks
Full Name	Building Automation Controls	Serial Communication Protocol	Local Operational Networks
Developed By:	ASHRAE	Modicon Inc.	Echelon Corporation/ Motorola
Use	Communication across devices	Connection between devices	Networking devices through power lines, fiber optics, and other media
Markets	Industrial, Transportation, Energy Management, Building Automation, Regulatory and health and safety	HVAC, Lighting, Life Safety, Access Controls, transportation and maintenance	Home automation, industrial, transportation, and public utility control networks.
Examples	Boiler Control, Tank Level Measurements	Tasks such as request temperature reading, send status alarm, or fan schedule	Security, lighting systems, HVAC, machine control, manufacturing, metering
Proprietary	No	No	Yes
Transmission Modes	Ethernet, IP, MS/TP, Zigbee	ASCII, RTU, TCP/IP	MS/TP, network, SNVT
Standards	ANSI/ASHRAE Standard 185 ;ISO-16484-5; ISO-16484-6	IEC 61158	ANSI/EIA 709.1; ISO/IEC 14908-1, 14908-2, 14908-3, 14908-4
Costs	Low; No charge for usage or licensing fees	Low; No charge for usage or licensing fees	High (proprietary); Limited users (exclusive to actual members;  mostly manufacturers)
Network Interfaces	Existing LANs and LANs infrastructure	Traditional serial and Ethernet protocols	U10/U20 USB Network Interface; i.LON SmartServer; i.LON 600
Testing	BACnet Testing Labs	Modbus TCP Conformance Testing Program	Products must  conform to LonWorks protocol
Advantages	- Scalability between cost, performance and system size	- Easy connection to Modicon	- Web based tool; saves time and cost
	- Endorsement and adoption by nearly every major vendor in North America and many other countries	- Suitable for small/medium volumes of data (≤255 bytes)	- Numerous developers of LonWorks products in the market
	- Robust internetworking including multiple LAN types and dial-up	- Data transfer designed for industrial applications	- Less Architecture at device level
	- Unrestricted growth and the ability to add new innovations and new features anytime	- Openly published and royalty-free
		- Easy to deploy and maintain
		- Moves raw bits or words without placing restrictions on vendors
Disadvantages	- Limited the number of field devices that can connect to a master station except Ethernet TCP/IP	- Limited the number of data types; Large binary objects are not supported.	- Outdated
	- MT/TP-Wire Length	- No standard method for a node to find the description of a data object, i.e. finding a register value represents a temperature between 30◦ and 175◦.	- Controlled devices & variables are connected to a separate control device. (Not recommended due to network interruptions producing system failures)
	- Ethernet-Infrastructure	- No security against unauthorized commands or interception of data	- Extensions are allowed only through the LonMark Consortium.
	- New standard has security standard but not implemented in all devices	- Transmissions must be contiguous which limits the types of remote communications devices to those that can buffer data to avoid gaps in the transmission.	- Hardware specific, and requires the Neuron chip for network movement of the protocol.
		- Great amount of configuration and programming required	- Close to “plug & play” ability, yet still far from achieving interconnectivity using Microsoft Windows.
		- Protocol is not common in the SIMATIC family

To determine whether a BMS protocol is open, ask the vendor two simple questions:

1.     Can your competitors exchange data with your BMS?

2.     Is the system’s protocol published in such a way that it’s easily accessible to everyone (including competitors)?

Even the ASHRAE BACNet committee has convened a working group to define use of XML with BACnet systems. The group is also working to define web services that will enable data exchange between building automation and control systems and various enterprise management systems.

Use these criteria when you’re choosing devices and BMS:

1.     For devices such as RTUs and refrigeration controllers, look for ones that use open protocols such as BACnet or Modbus.

2.     Make sure these devices give you both “read” and “write” capabilities so you can change set points.

3.     For easy enterprise access, choose a BMS with web services and XML capabilities.

4.     Make sure the web services of the BMS allow both read and write capabilities.

5.     Be sure the BMS supplier provides the XML dictionary and definitions of web services to anyone, including competitors.