Posts tagged surveillance

video cassette recording (VCR)

Today, security camera system may consist of various products and technologies. Many suppliers build pieces of the system if it is part of a hybrid analog / digital implementation or an end to-end IP network solution. The following sections describe the development of the CCTV system, starting with a fully analog and adding components until it reaches the network capacity.

A traditional analog surveillance system consists of analog cameras, time-lapse video and monitors. A coaxial cable connects each device to a multiplex device, which allows recording of multiple cameras, a VCR, a monitor for display. The time-lapse video recorder allows the operator to adjust when the VCR to the standard two-hour VHS tapes can be used to record a lot longer. The results of the compromise in the images of lower quality in exchange for less frequent belt or overwrite the image.

Analog CCTV recording systems have the basis for monitoring and tracking of the last twenty years. This technology is extremely old and outdated and will quickly through digital recording technology, which today replaces more than 80% of all new installations.

Digital Video Recording (DVR)

A DVR is a computer with a video graphics adapter that connects to an analog camera via the coaxial cable 75 Ohm Force. The card also converts the analog signal into a digital signal is compressed and the resulting image so that they can be on an internal hard disk is displayed, stored or transported over a network. DVR typically use an operating system like Windows or Linux as well as the video management system (VMS) software. DVRs can be controlled and install the keyboard, mouse and external monitor, run a software for monitoring and playback stored video retrieved. DVRs are generally an Ethernet LAN or WAN internal attachments.

network-attached digital video recorder (NOAC)

A connected network Digital Video Recorder is a part PC and part of “Network Appliance” A NOAC is very similar to a DVR and is sometimes called the “Network Appliance, because it does not require a shared keyboard, mouse or monitor. The device is connected directly to an Ethernet switch and the only way to access the device over the network . The device has an operating system yet, but he resides in the firmware in a chip burned on the motherboard. The left most of the load on the NOAC video management software (VMS) on a client PC connected to the network, but some have “embedded” in another mother chip, where they will be achieved by everyone, PC through a Web browser. However, while most of these products locally internal hard drives to store video files, but they can be combined with direct-attached Storage arrays (DAS), Network Attached Storage (NAS) devices or storage area networks (SAN) through the LAN or WAN.

network video recorder (NVR)

The “pure” network (NVR) is not a “field ready or Network Appliance, but created with a combination of network devices. An NVR is a standard network server with internal storage or fixed with a recording software, video surveillance or communications software, and perhaps even an intelligent video analysis software. The digitization of analog video is from another “Video Encoder or Video Server”, which is also connected to the Ethernet / IP made. With a configuration can NVR true IP cameras as video servers and input images directly to act on the NVR and will be managed directly by the NVR software video.

encoder and decoder

encoder used to make the video signals into analog or digital transmission capacity and promote them as the bandwidth or the storage is a problem. Encoding is true for many applications of video surveillance system where digital recording devices are used or not desirable on a network. The analog signals must first be converted into a digital format, but then, any source into a smaller file size or video “stream” to be compressed. There are different standards for encoding / decoding and compression has advantages and disadvantages of each. Typically, trade-offs of high quality for smaller file size.

A decoder is a device, the opposite of an encoder, release the coding, so that the original information can be found doing. The same method used to encode is usually interpreted only vice versa. These devices are relatively simple and can be software on a PC, DVD player or even a mobile phone are. You can also support devices, the digital video format and convert it back into an analog signal that can be displayed on a TV screen. This allows the video network will run on any output device. Usually, the functions of decoding and encoding of staying in the same unit and commonly called “codec” called an acronym for the encoder / decoder.

to a digital network solution

Migrating Since there is a significant financial investment in analog CCTV, many security officials opt for a gradual transition to IP, security technology combines analog and digital if possible during the migration. Integration of existing systems with analog products that offer the functionality of a digital system, several advantages:

remotely cost-benefit

flexible scalability

In the figure below simple, analog cameras are connected to a switch analog video, analog monitor, a VCR and a video server. This traditional configuration, monitoring and sequential acquisition of multiple analog cameras. By connecting to convert a video server to analog video into digital data, images can be sent over an Ethernet / IP (via a router / switch) that provides Ethernet connections for network IP cameras. With this configuration, the authorized personnel security locally or remotely video from analog and digital display IPcam network.
In the transition from analog to digital surveillance systems, no system is too small or too closely tied to analog technology, not to benefit from some degree of digital technology.

The result can be made the migration to a digital network solution for your existing system analogy, and still have the option to add the latest software and hardware.
Some recent software security system monitoring dual sensor as shown below.

The latest camera systems would be a Combani network cameras and video cameras are high-end analogy.