CCTV system rebuild

[Samsilvasound]

So I am looking to build a new CCTV system. I need to replace one that has been a nightmare the entire time. We have a couple of marshall cameras, and some black magic Sdi 4k Sdi distrobution boxes. The one shot is a FOH shot that needs to go to my monitor at FOH, to the SM, and to the conductor. The Second shot is an md shot, that goes to FOH, the SM, the MD, and Two monitors for the cast to see the md conduct. All of the components I have 3g SDI. I’d love to keep it that way, but as I am not really a video guy, i don’t really know where to start. I have done some CCTV stuff, but only on analog. I’m looking for something with the least amount of latency as possible. The current system works great(when it works) but more often than not, it drops signal to all of the monitors and flickers on and off like crazy. Super not helpful.

Thoughts?

 

[Joel Engelhardt]

How large is your venue?

If you're using 3G-SDI under SMPTE 424M, you'll start to push up against maximum cable distances before signal loss:
Belden Estimated Transmission Distance at Serial Data Rates

You'll see that most 3G-SDI cables can only run 200 – 300 feet before needing reclocking with an external device. Will this work for you?

Also, make sure to pay attention to what SDI Level the devices support. Blackmagic devices default to Level B, while other manufacturers only support Level A.

 

[Jay Ashworth]

Since you're using it for music sync, yes, you need to keep the delay down as far as possible.

It is *theoretically possible* to get SDI down to a frame or two, by carefully selecting all the components (there are many ways to do digital video, and if delay isn't critical, the other ways are often cheaper).

Two frames of p30 is 66ms, which is discernible by the trained eye, IIRC.

If you're dropping signal, though, and everything else is ok, you might want to look at putting driver-amps at the cameras, assuming your problem is just long-runs of marginal cable. That's effectively a 1x1 splitter, and depending on the circumstances, it can help because it's *only job* is driving the cable,

 

[FMEng]

It could be as simple as substandard cable. SDI is pretty picky about it.

 

[themuzicman]

It depends on how complex you want to get with it, and how much money you're willing to drop. SDI gets expensive quick.

The standard in NYC at the moment is the BlackMagic Smart Videohub, which comes in as small a count as 12x12. You're looking at either distributing 2 video shots with 2 screens at the stations that need it all, or somehow letting stations toggle between shots - either by getting video monitors with 2 inputs and letting folks select, getting monitors with 1 input and something like a BlackMagic Smart Video Controller to toggle shots (or you can DIY it with some QLab/OSC/BlackMagic integration via Bitfocus Companion), or by getting something like a Decimator Quad and sending everyone a quad view.

For rack-mount screens I've been using Marshall screens - both single 17" and dual 10" versions. I haven't been doing conductor shots in SDI, for that I've been going analog, and distributing analog to 32" Pelco screens on the balcony rail, and breaking it into the Blackmagic system via a Blackmagic MiniConverter. Keeps latency low where I need it.

 

[Rainmaker]

Sorry for necro posting but this came up in search.

I have similar requirements to the above...2 monitors on the balcony rail for performers seeing the conductor run from a camera in the pit. 1 monitor SL and SR for stage management and cast as well as one in the pit for the conductor to see the stage run from a camera on the balcony rail.

I've cobbled together cheap Amazon crap for a while now and it's always frustrating. Is there a "gear list" that might be helpful here? Live video is not a forte of mine so an ELI5 thing would be super helpful

 

[macsound]

Atlona HDBaseT is my protocol and hardware of choice because you can reliably get 328' of cat6a.
Installation of cat6a is in the wheelhouse of most contractors because it's so common. You just need to have them make the runs and you can install the equipment.