Defining the Differences Between IP and Analog
The CCTV industry is abuzz with talk of an IP (internet protocol) camera takeover. Yet reports of the death of analog cameras are premature. While some IP (or network cameras as they are sometimes called) versions can potentially deliver higher resolution images, analog CCTV cameras continue to offer greater efficiency, lower cost and reliability overall. Before deciding on IP cameras versus analog, it is advisable to first understand exactly what an IP camera is, and is not.
What is an IP Camera?
An IP camera is a video camera which can be accessed and controlled over any IP network such as a WAN, LAN, Intranet or Internet. By utilizing a standard Web browser or remote monitoring software over a network connection, users can view an IP camera’s live video from any local or remote location. IP cameras are available in the same styles as traditional surveillance cameras such as Pan/Tilt/Zoom, domes, bullets, box, infrared, covert and wireless.[IMAGE]2.jpg[/IMAGE]
How Does an IP Camera Work?
What is commonly known as an IP camera, in reality, is a digital camera which processes analog images, encoding them internally, and then transmits the digital video information over an Ethernet connection to a computer or similar device. It is the transmission method that makes it an IP camera. An IP camera can have either a CMOS or CCD sensor.
Typically, IP surveillance cameras are equipped with an embedded Web server and on-board encoding and processing. The network camera combines the capabilities of a camera with some PC functionality. As such, they do not require a direct PC connection to operate and can be placed anywhere along a network. The IP camera is a network appliance just like any other PC on the network, has its own IP address and connects directly to a wired or wireless network.
How Does an Analog Camera Work?
An analog camera also starts with the CCD or CMOS sensor and then digitizes the image for processing. But before it can transmit the video, it needs to be converted back to analog so it can be received by an analog device such as a TV monitor.
Difference Between Analog and IP Camera
The principle difference between analog and IP cameras is the method by which the video signal is transmitted and, ultimately, where the video is compressed or encoded. Again, the term “IP” in IP camera or “network” in network camera refers only to a transmission method.
It is important to understand the majority of the IP CCTV cameras sold are actually analog CMOS or CCD cameras that simply transmit video digitally. While this sounds confusing, we have to come back to how the video information is first captured. Analog sensors convert light to digital information and then convert that information back to analog in traditional CCTV cameras. If transmitting digitally as IP or network cameras, it has to be encoded (digitized and compressed) to travel along a network.
Which is Better: IP or Analog?
Cabling Infrastructure – One perceived advantage of network cameras is the ability to use an existing wiring infrastructure to support a surveillance system. Whereas legacy cabling for analog cameras utilized coaxial cables, today integrators can use baluns to transmit video over twisted pair including Cat5 network cable. Using baluns and twisted pair, analog video can be transmitted much longer distances than with coax. Video baluns come in different sizes, shapes and are available in both active and passive devices. They connect to both ends of your cabling and can follow many common standards such as 568B. Since baluns can transmit analog video, power and data over category cabling, for cabling purposes there is no advantage of IP over analog cameras.
Video Transmission – Regardless of whether video is transmitted over Cat5 or coax there are important differences between analog and network video traffic. Analog video traffic is an uncompressed and not subject to any networking issues or risks. It is a passive connection, similar to an analog telephone connection. IP traffic, like VoIP, is subject to a myriad of potential faults from bandwidth limitation to network congestion, bit rate, file sizes, load balancing, viruses, etc. If the network fails, the recorded or monitored video will suffer.
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