Switch = Matrix?

[kennefu]

Hi all,

I'm speaking exclusively in regards to blackmagic products. So mainly sdi and hdmi inputs/outputs.

My understanding is that a switcher has multiple inputs and outputs like a matrix, except with a switcher it is also capable of transition effects. Are the transitions the only difference? Obviously a dedicated matrix usually has many more inputs and outputs.

[Borggren]

A matrix is a switcher with more than one output. When switching between different sources, on a matrix or simpel switcher, you loose synchronisation on the output, since the input signals are not synchronised. If the output is going the ie a projector, you will probably see the picture rolling or blue/black for a short moment, during the switching.
When using a switcher with seamless switching, the inputs are frame synchronised, and there is a scaler on the output that makes sure that outgoing signal is always the same resolution, scan rate etc.
BM videohubs are made for overall routing of signals. If you want live switching, including clean cuts, between different inputs, the solution from BM is their Atem switchers.
Alternative seamless switchers are Kramer, Extron, TV one.

[sempei13]

Let me add that entry level video switchers (not selectors) often only have one output. This would be like have an audio mixer with no auxes, like one of the entry-level Behringers you can pick up at Guitar Center. There are matrix switchers, but you're looking at a much more expensive unit. A datavideo or entry-level panasonic won't do what a $250,000 Grass Valley or Ross will.

There's also the issue of frame sync vs. genlock. Video has to be timed to switch seemlessly. An expensive switcher won't interface with your camcorder without some outboard gear. An entry-level switcher with built-in frame syncs will, but usually at the cost of latency (which is deadly for imag if you have more than a couple of frames of latency).