Mass Media & Technology

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(December 2012)

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DK
DanielK
In our school when there is a concert or a show on, there is a camera on the walkway pointing at the stage, that is attached to a projector at the side pointing at a blank wall, I figured that out easily. The bit I'm confused about is that there are classrooms behind the stage area for the next acts to get ready etc, and there is ually a live stream of the projection on their screens, does anyone know how this may have been done? It will probably be a very cheap solution because our council is..cheap to say the least!.

Dan
LO
lobster
Probably just a VGA splitter and a VGA over cat 5 box. Depends on how its wired, but splitting a VGA or video feed can be done with some off the shelf products for a few quid.
DK
DanielK
The thing is, the classrooms are on the ground floor, with the camera and projector on the walkway at first floor level, and the walkway is quite far away from those classrooms and there is no integrated Video cables, just Audio ones for our sound desk
GS
Gavin Scott Founding member
You're describing a "show relay", where a (usually) static shot of the stage is distributed backstage for the benefit of technical crew. It is seldom provided for the benefit of other performers or an audience.

But in answer to your question, sending a video signal down a wire to one or more locations from a live camera is pretty straightforward and can be done for tens of pounds, not hundreds or thousands. Cheap.

EDIT - pardon me I missed your reply.

They could be utilising a video balun (http://en.wikipedia.org/wiki/Balun#Video). That will send a video signal along a network cable, which is almost certainly running round their building, or possibly some wireless video sender.
Last edited by Gavin Scott on 17 December 2012 11:29pm
DK
DanielK
The bit about it not being for the audience, its like at a comedy gig, there may be screens high above the 'set' that shows the act.
GS
Gavin Scott Founding member
The bit about it not being for the audience, its like at a comedy gig, there may be screens high above the 'set' that shows the act.


Comedy clubs are often bars with a small stage and have poor sight lines for much of the audience.

Theatres and larger dedicated performance areas are different - theatrical productions tend not to look terribly good from a fixed camera - they're typically used for the stage manager to check for clearance before cueing lighting, sound, the fly-floor and other departments. Occasionally they will distribute the video to a front of house area like the bar, but its not designed to be watched per se.
DK
DanielK
Its much like this, but with just a left screen.

http://dx9rjq5h30myv.cloudfront.net/wp-content/uploads/2009/09/michael_mcintyre_edit_1.jpg
DO
dosxuk
Do you have network points in both rooms?

If so, sending audio & video between them should be trivial and cost only a few quid, hardly bank breaking.
DK
DanielK
The camera point doesn't have a network point, but we can get a Ethernet cable reel and plug into one of the classrooms nearby, the viewer rooms all have network points and VLC Player, could I do a network stream over that? Or is that something different?
BA
bilky asko
Do you have network points in both rooms?

If so, sending audio & video between them should be trivial and cost only a few quid, hardly bank breaking.


Considering most classrooms nowadays have plug sockets and network ports lining the room, I'd imagine that's the case.

The camera point doesn't have a network point, but we can get a Ethernet cable reel and plug into one of the classrooms nearby, the viewer rooms all have network points and VLC Player, could I do a network stream over that? Or is that something different?


I would imagine the camera output is being fed into a computer that will distribute the video over the network.
DO
dosxuk
If it's something that's already installed, the quickest, easiest and most accurate answer would be gained by tracing the cables. There are tons of ways this could be done, and it is basically impossible to guess.

If it's something you're wanting to set up then again, there's several options.

Also, don't assume network points are carrying ethernet data. Analogue video can be sent over it for a few quid, not going anywhere near a computer.
JO
Jon
OK I'm going to say it. This relates to television presentation how?

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