The role of the audio and video matrix

Modern multimedia conference room, in order to meet the needs of different shows occasions, usually with a variety of different audio and video signal source and display terminals, although these audio and video signal source and display terminals or with composite video (Composite-Video), super video (S-Video), component video (Component-Video) or digital video (DVI, SDI) interface, but now in multimedia videoconferencing are commonly used or composite video matrix, the main reason in the following areas: · Composite video with good stability, compatibility and interoperability, transmission bandwidth small distances. But the chromaticity and luminance shared 4.2MHz (NTSC) or 5.0 ~ 5.5MHz (PAL) of a frequency bandwidth, each with relatively large crosstalk, equipment and transport requirements for standard cables, signal source, embedded cable · investment low. Super Video (S-Video) while reducing the luminance loss, brightness/color crosstalk in clear advantages over composite video, but for the present common LCD projectors, DLP projector does not reach the very obvious difference and embedded cable investment is twice as composite video, so the project is not universally by long distance transmission. · Component video signal format level has been significantly higher than composite video and super video, but for now most of the rooms is for computer display (VGA or RGBHV signal formats) services, equipment and transmission cables require a high level (depending on the intended design standards and investment budget), embedded cable · investment is high. Similar R-Y, Y, Y, B-Y, Cr, Cb component video signals are now mainly used in radio, film and television industry, and will gradually to SDI or HD-SDI transition of digital signal format, because the signal source and capital budget constraints, the Conference room use. DVI signal due to the effective transmission distance (5 meters), there is no widespread use. The service that IMIS habits on audio and video matrix no special indication that the default is the composite video format. To the composite video format output of the main equipment: camera, physical stand, cable TV modem, remote video conferencing, video tape recorder, DVD player, audio and video matrix system in the video source and display or multiplexing Terminal, will among different audio/video signal source according to user's preference for centralized control. In accordance with the input and output channel, common video matrix generally have 8 × 8 × 2, 4, 8 x 8, 16 × 16 × 4, 8, 16 × 16, 32 × 32 × 8, 16, 32 × 32, 64 × 64 × 16, 32, 64 × 64, 128 × 128, etc. General understanding that multiply the preceding figures represent the number of input channel, take the number behind the figures represent the number of output channels. Whether matrix input the number of output channels, their control methods are more or less the same: the front panel pushbutton control, isolation keyboard control, third-party control (RS-232/422/485, etc.), and can achieve the following functions: 1) can use needs in different display Terminal at the same time show the same or a different video source content 2) you can set the camera, DVD player, VCR, cable TV, video conferencing, and other various video signal for convenient handling and call 3) administrator can monitor any one channel video signal, but does not affect other terminal display content and effect 4) administrators can on any video signal recording, but does not affect other terminal display of content and results 5) administrators can designate any one channel video signal sent to the meeting of the terminal or other tracks, but does not affect other port displays the content and effect, like the matrix with BGBHV design a basic principle of video matrix is based on the signal source and display the number of Terminal number to determine the rank of a matrix, the matrix of difference (the number of channels) in price reflects the very obvious, in certain cases, the budget, so select a matrix of channels will become more sensitive, for future expansion is also a challenge. In addition, the following describes some problems as equipment selection factors to be considered.