A video router, also known as a video matrix switch or SDI router, is an electronic switch designed to route video signals from multiple input sources such as cameras, VT/DDR, computers and DVD players, to one or more display devices, such as monitors, projectors, and TVs.

Inputs and outputs

The number of inputs and outputs varies dramatically. Routers are normally described by a ''number of inputs by number of outputs'' e.g. , , . Some video routers, by the use of additional drop-in cards, allow the system to be expanded for more inputs or outputs, or to support other formats.

Signals

The signal format that the router transports can be anything from analogue composite video using PAL and NTSC. Also multi-format routers can route more than one

Digital video Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data. This is in contrast to analog video, which represents moving visual images in the form of analog signals. Digital video comprises ...

signal format,

serial digital interface Serial digital interface (SDI) is a family of digital video Interface (computing), interfaces first standardized by SMPTE (The Society of Motion Picture and Television Engineers) in 1989. For example, ITU-R BT.656 and SMPTE 259M define digital ...

(SDI), HD-SDI,

component video Component video is an analog video signal that has been split into two or more component channels. In popular use, it refers to a type of component analog video (CAV) information that is transmitted or stored as three separate signals. Compo ...

. Some routers have the ability to internally convert digital to analog and analog to digital. For HD Video, HDMI Matrix switch can be used to switch any

HDMI High-Definition Multimedia Interface (HDMI) is a proprietary digital interface used to transmit high-quality video and audio signals between devices. It is commonly used to connect devices such as televisions, computer monitors, projectors, gam ...

source to any connected HDTV using a HDMI connection. More recent developments have allowed audio embedding and de-embedding within the router, this allows for audio to be routed along with video.

Crosspoints

Because any of the sources can be routed to any destination, the internal arrangement of the router is arranged as a number of crosspoints which can be activated to pass the corresponding source signal to the desired destination. This architecture has guaranteed bandwidth and is non-blocking. Crosspoints can also be switched in the vertical interval to avoid losing picture information, for this the router would need to be genlocked to either black and burst or tri-level sync.

Control

Many types of

broadcast automation Broadcast automation incorporates the use of broadcast programming technology to automate broadcasting operations. Used either at a broadcast network, radio station or a television station, it can run a facility in the absence of a human oper ...

systems can be used to control a video router via IP or

serial communications In telecommunication and data transmission, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits ar ...

such as RS-422. Video routers can also be controlled by other types of user interfaces, including front panel buttons, IR remote control, or application software running on a PC. Video Matrix Switches and Bandwidth
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Future prospects

With the advent of 4K/UHD TV, the traditional 'baseband' video router has become something of a victim to the data rates. UHD TV requires 3840x2160P @ 50 Hz or 60 Hz. Traditional crosspoint based devices have therefore been reduced in size by a factor of 4 as the UHD signal is split into 4x1080P@50 Hz/60 Hz 3 Gb/s streams. A few smaller manufacturers (Blackmagic Design, Utah Scientific, Ross Video, PESA) have taken on 12 Gb/s routing over copper coax cable and fiber. Although their router sizes cannot compete with the ~576x1152 size of HD routers, and the distance achievable on copper is somewhat limited. This may mean that baseband architectures start to migrate over to IP based infrastructures. Where UHD TV can be transmitted (albeit compressed) over a single 10 Gb/s link using IT hardware.

Manufacturers

Ampex Ampex Data Systems Corporation is an American electronics company founded in 1944 by Alexander M. Poniatoff as a spin-off of Dalmo-Victor. The name ''AMPEX'' is an acronym, created by its founder, which stands for Alexander M. Poniatoff Excell ...

* Blackmagic Design * Evertz Microsystems * Imagine Communications * Pulse-Eight *

Sony is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (i ...

* Thomson Grass Valley

References

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