CCTV for cueing music performance

[supervision 0]

Can anyone advise me please... I need to arrange a CCTV system for use in a recording studio. The idea is that two or more musicians would perform music while located in different rooms. In order to play "in sync" it helps if they have visual contact with one another -- that's what the CCTV is for.

 

There's no need to record the video signal. Basically all I need is to simulate having a "window" between the rooms. However there is a requirement for low latency. The image appearing on the monitor must be Real Time or very close to it; there can't be any appreciable delay in reproducing what's in front of the camera. At a guess I'd say 30 or maybe 50 milliseconds would be a reasonable limit.

 

NTSC video would be adequate, and -- being analog -- it sidesteps the latency issue. But I'd like to use flat-screen displays, to save space. Optionally it'd also be nice to have split screen capability (to show 2 or even 4 images on one monitor).

 

Do I have to go digital to achieve this, or should I use a mix of analog & digital? There's so much equipment available, and latency usually isn't listed in the specifications!

 

Suggestions appreciated -- thanks!

[scorpion 0]

You need two inexpensive cameras (usually bullet style), two power supplies (most cameras do not come with them, but some do), and you need two TVs. You can pick the TVs up from a pawn shop to save cash.

 

You will need to plug the power supply in to the wall. It is wired to the camera in room A. The video from room A goes to a TV in room B.

 

Duplicate this for B to A.

 

Now comes the tricky part. If you want to see both video feeds in the control room then you need two of these.

http://www.radioshack.com/product/index.jsp?productId=2103065

 

In this setup I would run the two camera video feeds in to the control room. Split the camera signal from A, and then hook one feed to your TV for room A, and run another feed in to room B. Take video feed from room B, and split that. Hook up one feed to your B monitor, and run the second feed to room A.

 

If you are dealing with BNC camera cables then you will need this to plug in to the yellow video input on the TV.

http://eclipsecctv.com/ECL-1010_connector.html

 

How does that sound, or should I say how does that look?

[supervision 0]

Thanks - I wasn't even sure if NTSC cameras were still available!

 

I have mixed feelings about using a TV as a monitor, although I appreciate the suggestion that I could save some cash. But it might be worth the price in order to avoid a CRT, which is bulky and emits 60 Hz magnetic interference that could be a nuisance in the Recording Studio setting. Do modern LCD televisions still have analog inputs? (Sorry if these seem like dumb questions -- I'm actually very knowledeable about electronics but I gave up watching TV decades ago!)

 

Finally, what would it take to get 2 pictures on one LCD screen? Maybe it'd be more sensible just to use two screens...

 

Thanks again!

[Soundy 1]

You'd need either LCD TVs (to avoid CRTs), or composite-to-VGA converters to use cheaper LCD computer monitors.

 

If you want to simplify a bit, you could use a quad or multiplexor to generate a 2x2 split-screen display (four images), then use an active video splitter to send that feed to your two rooms and the control room, so everyone sees the same thing.

 

If you wanted to be really trick with it, you could add a camera to the control room as well, so the musicians can see the producer/engineer, and another monitor there so they can see both musicians at once.

 

How big is your main live room? If it's big enough, you might even round things out with a second camera and monitor in that room, to fill up the fourth corner of the display. Or leave the channel free in case you add another iso booth later.

 

The fourth square could also include a video feed from a DVD or VCR, possibly input from a computer for displaying lyrics, or whatever else you might want to display there.

 

It's a really poor picture, but this gives an idea of what I'm talking about:

 

Finally, as pretty as LCDs are, I've used CRTs in studios for years and never had noise problems from them. As long as you're using balanced audio lines and don't run your wiring too close to the monitor, you should be fine - frankly, the video will look a LOT better and clearer on CRT than LCD, and you should be able to find larger models for really cheap (I've seen 20" TVs regularly going on Craigslist in the freebies section).

 

So, quick count:

2-4 bullet or dome cameras

video quad or four-channel mux

3-4 channel video splitter/amplifier

2-3 monitors

[supervision 0]

More good thoughts - excellent!

 

It rings true what you say about a CRT providing a better image. Likewise about the noise issue (60 Hz magnetic interference) -- some common-sense practices will usually prevent that. Unfortunately there's one instance that'll always be problematic, and that's an electric guitar that uses single coil pickups. So avoiding the magnetic field is still an issue, although not of overriding concern.

 

I'll have to educate myself a bit re: that multiplexor gizmo... I'm guessing there's some arrangement that allows all the cameras to use one common sync signal, but maybe it's actually buffering frames prior to display.

 

BTW it's unlikely we'll need to have cameras or monitors in the Control Room... It's interesting to speculate on a system that's "got everything" but there's not much justification for equipping the Control Room I'm afraid!

[Soundy 1]

More good thoughts - excellent!

 

It rings true what you say about a CRT providing a better image. Likewise about the noise issue (60 Hz magnetic interference) -- some common-sense practices will usually prevent that. Unfortunately there's one instance that'll always be problematic, and that's an electric guitar that uses single coil pickups. So avoiding the magnetic field is still an issue, although not of overriding concern.

 

Don't play your guitar within about 18" of the monitor, and you should be fine. Seriously, a typical CRT's field is NOT that big. CCTV monitors tend to be a lot better shielded than your average TV, too. I've built and worked in a number of studios, I know whereof I speak

 

I'll have to educate myself a bit re: that multiplexor gizmo... I'm guessing there's some arrangement that allows all the cameras to use one common sync signal, but maybe it's actually buffering frames prior to display.

 

Sync isn't really an issue with the split-screen; the only place sync issues tend to be noticeable is when doing a sequence (switching from camera to camera full-screen), where it can cause a flicker or a jump in the picture when switching.

 

BTW it's unlikely we'll need to have cameras or monitors in the Control Room... It's interesting to speculate on a system that's "got everything" but there's not much justification for equipping the Control Room I'm afraid!

 

Well, it's always good to have the future capacity... you'll be kicking yourself if you don't, and put it all in, and then think, "Ya know, that Soundy dude was right, it WOULD be really handy to have a camera in here too!"

[supervision 0]

Okay, well this has certainly been helpful. Some of these issues I'll have to discuss with the client -- it's not my own studio that we're discussing. But somehow I volunteered to be the "consultant" and to look into this!

Thanks again.

[Soundy 1]

Good luck with the rest of your project!

 

As for researching multiplexers, here are a few examples (not necessarily suggestions or recommendations): http://shop.ebay.com/?_from=R40&_trksid=p3907.m38.l1313&_nkw=4ch+multiplexer&_sacat=See-All-Categories

 

Models like the Pelco and Robot are very common professional CCTV units - before DVRs became a more cost-effective option, these were used extensively for recording multiple cameras to a single time-lapse VCR (other brands that we've used a lot of are National Electronics and Sanyo). If you decide to go the split-screen route, any of these are a good choice - you don't need to worry about camera sync or anything like that