Matrix Switcher questions

1

I’m building a video art installation with 8x analog screens (dell 2007fbp) on portable mounts.

I have several input sources (composite video) and want to be able to send those to the monitors in such way that we can change the routing during a show.

The routing part can be done with a Matrix Switcher, I think
I found a Extron MAV Plus 2412 for a low price, which has 24 composite inputs and 12 outputs.

My question is: How does this work with sync?
Does a matrix switcher provide the syncing for the seamless switching, or is it needed to sync the incoming signals beforehand?

If all signals have to be genlocked together, how is this done?
My analog sources, Recur / Waaavepool and such don’t have sync inputs.

1 Like
2

You don’t need to worry about sync. Matrix switchers just cut from one input to another, no sync is required. Unlike a video mixer, where two video inputs are shown at the same time and need to be syncronized (and the video mixer does this using a frame buffer, where some frames of each video are stored in memory and output with a sync generated by the mixer).
If you haven’t come across it yet, @cyberboy666 's _transcribe_ device could be fun for this project _transcribe_ – underscores

3

I’m talking about a seamless switcher, so sync is needed to switch during the blanking interval (if I’m correctly reading the manual of the Extron)

If the switch is done halfway, this might be noticable, I think?

4

I have two Extrons, the MAV Plus 88 and the MAV Plus 1616. I’ve never had an issue with sync between sources, but maybe I just don’t know how seamless it could be.

5

oh, then I might be mistaken :slight_smile:
thanks for the reply

I have never before used a switcher, and the extron manual is not so clear about this. it just hits that synced switching is “better” ?

someone over at the LZX discord made a test setup for me with his Extron MAV, it looks like it works just like you say.

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6

I was looking in the manual, and found the line you reference

The MAV Plus switcher switches between inputs during the vertical interval period, resulting in glitch-free video switching. The MAV switcher can use an external signal to synchronize switching during the vertical interval. Without the external sync locking feature, switching between inputs can result in a brief rolling (sync loss) or a brief change in the picture size.

So my guess is that since these are like pro-level devices, maybe in a production environment where you can’t have the tiniest bit of risk that it might sometimes flicker or roll, you have the option to sync. I looked, and my switchers do have a BNC Sync input on the back. My guess would be that like with other genlock devices, you can just pick any video signal to send to that sync input and it will use that. The example in the manual shows specifically using a sync generator, but in my experience (with the Canon XF105 camera, which has a genlock input) a normal composite video signal is also fine.

7

I think that if you would use it as intended, all sources are genlocked together.
but while that is possible with broadcast gear, the stuff I use does not have any external sync input
The solution to that might be using several Time base correctors chained together, one for each source. which would be much more expensive