science

Video router

Video router is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Video router rather than just read about it. In short: 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.

Key takeaways

Video router belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Video router to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Video router from memory before moving on to harder problems.

Reference excerpt

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. 2 × 1, 256 × 256, 576 × 1152. 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 signal format, serial digital interface (SDI), HD-SDI, component video. 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 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 systems can be used to control a video router via IP or serial communications 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.

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

References

Illustrations

Worked examples

Example 1 — a first encounter with Video router

Start with the simplest possible case. Write down what Video router claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Video router before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Video router ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Video router

In research: Video router appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Video router in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Video router is common in secondary-school and first-year university syllabi. It links to neighbouring topics Television technology, Television terminology, so understanding it makes those chapters shorter.
In everyday life: Look for Video router outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Video router in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Video router means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Video router out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Video router in simple terms?

Why does Video router matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Video router?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Video router.