Matrix Switcher is a device that allows any of its camera inputs to be switched to one or more of its monitor outputs. The outputs can of course also be video recorders.
MB Megabyte Mbps Megabits per second. A measure of bandwidth.
Mechanical Focus refers to the process of manually setting the focus on a lens
Mini-DIN Multi-wire cable with Mini-DIN connectors at both ends. Usually has 4 inner wires.
Motion JPEG -
Motion JPEG offers video as a sequence of JPEG images. Motion JPEG is the most commonly used standard in network video systems. A network camera, like a digital still picture camera, captures individual images and compresses them into JPEG format. The network camera can capture and compress, for example, 30 such individual images per second (30 fps – frames per second), and then make them available as a continuous flow of images over a network to a viewing station. At a frame rate of about 16 fps and above, the viewer perceives full motion video. We refer to this method as Motion JPEG. As each individual image is a complete JPEG compressed image, they all have the same guaranteed quality, determined by the compression level chosen for the network camera or video server.
MPEG is a standard used for coding and compression of moving images. It was developed by the Moving Pictures Experts Group in the late 1980s). It is now used widely for the compression of video images.
MPEG's basic principle is to compare two compressed images to be transmitted over the network. The first compressed image is used as a reference frame, and only parts of the following images that differ from the reference image are sent. The network viewing station then reconstructs all images based on the reference image and the "difference data".
Despite higher complexity, applying MPEG video compression leads to lower data volumes being transmitted across the network than is the case with Motion JPEG. This is illustrated below where only information about the differences in the second and third frames is transmitted.
MPEG-1 was released in 1993 and intended for storing digital video onto CDs. Therefore, most MPEG-1 encoders and decoders are designed for a target bit-rate of about 1.5Mbit/s at CIF resolution. For MPEG-1, the focus is on keeping the bit-rate relatively constant at the expense of a varying image quality, typically comparable to VHS video quality. The frame rate in MPEG-1 is locked at 25 (PAL)/30 (NTSC) fps.
MPEG-2 was approved in 1994 as a standard and was designed for high quality digital video (DVD), digital high-definition TV (HDTV), interactive storage media (ISM), digital broadcast video (DBV), and cable TV (CATV). The MPEG-2 project focused on extending the MPEG-1 compression technique to cover larger pictures and higher quality at the expense of a lower compression ratio and higher bit-rate. The frame rate is locked at 25 (PAL)/30 (NTSC) fps, just as in MPEG-1.
MPEG-4 is a major development from MPEG-2. There are many more tools in MPEG-4 to lower the bit-rate needed to achieve a certain image quality for a certain application or image scene. Furthermore, the frame rate is not locked at 25/30 fps. However, most of the tools used to lower the bit-rate are today only relevant for non real-time applications. This is because some of the new tools require so much processing power that the total time for encoding and decoding (i.e. the latency) makes them impractical for applications other than studio movie encoding, animated movie encoding, and the like. In fact, most of the tools in MPEG-4 that can be used in a real-time application are the same tools that are available in MPEG-1 and MPEG-2. The key consideration is to select a widely used video compression standard that ensures high image quality, such as Motion JPEG or MPEG-4.
MHz (megahertz) is a measure of frequency. 1 GHz = 1000 MHz = 10,000 KHz = 100,000 Hz.
Manual Iris Lens is a lens with a built-in method of manually adjusting lens aperture for the best video quality for a specific lighting condition. Iris control on such a lens is set by hand to a particular fixed aperture, allowing for the best possible (often better than auto-iris lenses) brightness and contrast for a specific camera angle / shot.
Maximum Recording Time indicates the longest continuous duration of time which could be recorded onto storage media using a VCR or DVR video recorder. Maximum recording time for ALL recorders will depend on the user setting for timelapse or realtime recording and the amount of storage media capacity. Maximum recording time for DVR recorders is also dependent on tvres settings as well as hard disk drive capacity. Maximum recording time for analog VCR recorders will depend on the size cassette tape, usually VHS, which is installed in the recorder.
Micro Board Lenses are standard lenses for many cameras. These types of lenses are visible (not easily hidden like a pinhole lens) and range in size from 14mm to 25mm in diameter. Because it is physically larger than a pinhole lens, a micro board lens is able to accept more available light to provide the lowest possible low light performance.
Milliamps (mA) is a measure of electrical current power consumption. 1 amp (A) = 1000 milliamps (mA).
Milliwatts (mW) is a measure of RF radio frequency energy output. This term is most commonly applied to the RF output power of wireless A/V transmitters. For these types of devices, a higher number of milliwatts of output power indicates a more powerful (and usually further broadcasting) transmitter.
Modulator refers to a device which is capable of transforming an analog video or audio signal (or other type of electrical signal) into an RF radio frequency for wired installations. Modulating video into RF allows for longer cable runs in hardwired surveillance systems. Modulators, often called wired transmitters, also require a demodulating piece of equipment to reconvert the RF signal into a typical analog audio / video signal for proper display on a television, monitor, video recorder, etc.
Monitor used to view video pictures. These devices do not normally have television RF frequency receivers. They normally have composite or component video inputs
Monitor Screen Size indicates the actual physical size of a monitor's viewing screen. However, this measurement is often different than the actual part of the monitor which produces a picture. The monitor viewing size spec describes the size of the picture on a monitor.
Monitor Viewing Size indicates the size of a monitor's actual visible picture.
MOS Metal-oxide Semiconductor. One of video image chips like CCD, but it produces lower quality video.
Motorised Lens A camera lens equipped with small electric motor that enables focusing lens, opening or closing the iris diaphragm, or changing the focal length.
Monochrome refers to video captured in one monotone color scheme. For practical purposes, monochrome is another word for black and white in the video surveillance camera industry. Black and White signal.
Multiplexer (mux) is a video switching device that accepts video input from multiple cameras and converts them to all display on one monitor and / or video recorder, similar to a quad video processor. However, a multiplexer is far more advanced than a simple quad processor. Video multiplexers use time division multiplexing, meaning that a full frame of video from each camera is recorded every few seconds. While multiplexed video does not achieve true realtime display or recording (there is a slight drag to the images on playback), multiplexers do offer the capability to change between a view of several cameras and a solid close-up view of only a single camera's view on playback of recorded video. When using multiple cameras, quads and multiplexers help to cut down on the amount of additional equipment needed for a dedicated surveillance system. However, DVR digital video recorders with multiple video inputs are quickly replacing quads and multiplexers. DVRs are now capable of doing what required a processor and VCR in the past (plus a whole lot more). |
