The turbulent winds of technological change have finally blown away the barriers to viably monitorin
With the growing popularity and use of the Internet, a lot of focus is being put on the surveillance industry and the use of remote video via the Internet. With the cost of hardware and bandwidth constantly decreasing, many people have begun to stream video over the Internet and broadcast places and events, even in real-time.
Here, we’re faced with a different challenge. Instead of many people watching one camera, how do you get one person watching many cameras, all over the world? As with any installation, there are technical considerations for transmitting a CCTV system over the Internet. Multiplexing, bandwidth, compression, transmission and privacy are among the aspects that must be addressed.
Digital Multiplexer Is Best Bet for Multiple Cameras
If CCTV systems all consisted of only a single camera, the task of video signal multiplexing would be simpler. However, most systems are composed of many cameras. Some remote video systems have between one and four inputs. This is fine if you have four cameras or less. However, if you need more cameras than that, a digital multiplexer is your best route. These muxes take numerous cameras and convert them into a single video output. Most of the multiplexers also support pan/ tilt/zoom (P/T/Z) and alarm functions as well as local recording with either a traditional time-lapse recorder or digital video recorder. This single multiplexed output is especially important because of bandwidth considerations and frame rate.
Greater Bandwidth Speed Improves Video Quality
Bandwidth is the amount of data that can be passed along over a certain period of time. Within the past decade, bandwidth speeds have gone from an average of 1,200bps (bytes per second) to an astonishing 57,600bps. Now, with the growing use of broadband (DSL, cable, ISDN, T-1, etc.), you are able to connect at speeds 100 times to 200 times that, and it is ever increasing. What does all this mean? Using a dial-up 56k modem, in more than an hour, you could capture about 11,200 video frames (using JPEG compression at approximately 18k/frame). That means you’d be transmitting about three frames per second. Using a broadband DSL connection, you could have 77,200 of the same frames. That means you’d be viewing 21 frames per second. Plus, you’re always connected to the Internet. There’s no dialing and no more getting lost by your carrier.
JPEG, MPEG Formats Are Top Compression Methods
Simply digitizing video is not enough. In order to view real-time video over the Internet, it must first be compressed. So, what is compression and why do you need it?
Compression is a way of more efficiently encoding the video using logical algorithms, so it takes up less space. There are many different types of compression. The two most common are JPEG (Joint Photographic Experts Group) and MPEG (Moving Picture Experts Group). JPEG format analyzes each scene and removes information in adjoining pixels before linking the images together as a stream. JPEG compression offers very good quality and a uniform file size since it is composed of multiple images. MPEG compression compares the frames and only records the changes in the image. Therefore, a video in which there is more activity will take up more space than a still scene. Either format works well for remote viewing, but when considering digital storage, JPEG is a better choice because it is easier to calculate storage requirements and file sizes.
Transmission Requires a Networking Device
Let’s actually put your CCTV system onto the Internet. The system must be connected to a device capable of networking, preferably with TCP/IP (Transmission Control Protocol/Internet Protocol, the standard protocol for transmitting data over the Internet), since it will be connected to the Internet. This device must also contain some type of Web server. You can then assign it an IP address (an address that uniquely identifies a node on a network) and connect it to the Internet or your LAN (local area network). If the system has a public IP address, you may connect to it from anywhere in the world and view your camera system. If it is a local IP address, you will be able to view it from other computers within your network. Depending on the capabilities of the transmitter, you may even be able to view it through a common Web browser, remotely administer your system, or even control your cameras. The transmitter, or video server, is mainly responsible for video compression, IP-based video transmission and communications.
Encryption Helps Ensure Security, Privacy
It’s great to be able to remotely view your systems over the Internet, but there is often a great need for security and privacy. The most common way to accomplish this is with encryption, a way of scrambling a transmission at the source and decoding it at the destination. One good way is using SSL (Secure Sockets Layer), which is capable of 128-bit encryption (banking standard) over a regular Web browser. SSL uses certificates to verify the source of the transmission through a third-party CA (Certification Authority), such as Verisign or Thawte. Another good way is using a VPN (Virtual Private Network). VPNs use a special piece of hardware or specialized software. While your system will be connected to the ‘Net, it can only communicate with certain other machines that also consist of this hardware or software. That’s often satisfactory.
Questions, Experience Bring About Experts
Like any other new technology, your first installation is the most challenging. Simply get your ducks in a row. Write down your specifics concerning: 1) video inputs; 2) bandwidth; 3) video compression; 4) video transmission; and 5) security and privacy issues. Ask questions of your hardware and/or system providers. Ask also about the ease of installation, scalability, simplicity of the GUI (graphical user interface) and the new system’s compatibility with existing and future cameras or hardware.
Michael Daniels is senior manager of technology for RemoteVideo.com in Santa Ana, Calif. He can be reached at (949) 580-3636 or firstname.lastname@example.org.
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