Video cable distribution...

[J Pearce]

You can get passive baluns for both VGA and composite, but long VGA runs usually benefit from active baluns. I've had passive baluns running to 300m on composite video with good image quality before on a pair of these.

 

The better active baluns usually support phantom powering, so you only have to power one end.

[Ynot]

Hmmm... ©

 

OK, I seem to be swaying back towards Cat 6 now then. :)

 

 

 

[David Lee]

Either has got to be better than just composite :)

[AHYoung]

the point is probably that theres no standard way of getting video to go any distance without converting it to something else other than via hdsdi. the convert to something else devices on the most part use catX cable and some use the shield as a conductor and the better the cable the further it goes. so by a process of elimination fit hdsdi cable and shielded cat 6 and you will be able to get pretty much anything from a to b plus have extra network lines and the ability to squirt the all important composite video to all the 9" monitors without any trouble. compromise slightly on the cable quality and all the time and efforts wasted as its unusable. Ive used BELDEN 1855ENH cable and seems fine in 100m runs at hd, not saying its best, but ive used enough of it to know it works...

[Joe Fernand]

Agree with folk re CAT6 being a good ‘standard’ which (with suitableelectronics) will carry most/all current video formats.

 

 

For HDMI or any signal ‘converted to HDMI’ you have a few'extender' options!

 

 

HDMI over dual CAT (sub £180)– will carry HDMI (up to 1080p),plus IR out to 40m and can be PoC so only requires power at the Tx.

 

 

HDMI over HDBT (approx. £350)– single CAT, 10/100 Ethernet, HDMI(up to 2160p), IR, RS232, out to 100m and again can be PoC.

 

 

HDMI over HDBT-lite (approx. £270)– single CAT, HDMI (up to2160p), IR, RS232, out to 70m and again can be PoC.

 

 

HD over LAN (approx. £300)* – single CAT, HDMI (up to1080p), out to 90, uses MJPEG compression (most folk wouldn’t notice).

 

 

*HD over LAN combined with a Gigabit Switch can create a lowcost Distribution or multi-source matrix.

 

 

Joe

 

[timsabre]

HD over LAN (approx. £300)* – single CAT, HDMI (up to1080p), out to 90, uses MJPEG compression (most folk wouldn't notice).

*HD over LAN combined with a Gigabit Switch can create a lowcost Distribution or multi-source matrix.

 

There is a significant delay though which is noticeable (and may be unworkable) in live applications.

[Joe Fernand]

' There is a significant delay though which is noticeable (and may be unworkable) in live applications' - agreed you would need to test this one in your application.

 

Joe

 

 

 

[Owain]

the point is probably that theres no standard way of getting video to go any distance without converting it to something else

 

CCTV runs over 100s of metres using Cat5 with passive baluns and they're pretty cheap (a few quid each)

[Dave m]

but that limits you to cctv quality

 

Fair enough, that's what he has asked for, but HS-SDI works out cheaper, and is "transparent" as far as the original request, in that it behaves exactly like a non HD cable if needed to do so.

 

If it was me, potentially with my head in a false ceiling/down a hole/etc, I'd add CAT 6 as well. The cable costs are nothing compared to the time/labour, even if they remain tucked into the ceiling, and you never know when you may need to for instance fit a digital multicore to each end

[Tim gregory]

If it is a choice between HD-SDI cable and CAT5/6 personally I would install the HD-SDI.

 

Cat5-HDMI converters can be very limited on distance.

 

There is cheap HDMI-HDSDI converters available these days and I have found these much more reliable over distance than Cat5.

 

Obviously if you can do both SDI and Cat5 then even better.

 

Tim

[Ynot]

I have to say that on the whole, the majority of VT we'll be sending won't be HD and some (think dance school content...) will be FAR from it! :(

 

As I mentioned, I'm not after looking at providing for high high def in the near future because I'm hoping we have a MAX of 4 or 5 years in the current space, and when we design the new venue a lot of this stuff will be part of the overall plan and that WILL be viewed with some definite future-proofing in mind.

 

As long as I can do something to remove the time lag that we have on a couple of lines now, and maybe up the capacity for multiple feeds, I will be happy with SD for the time being.

 

I'm assuming that the CAT5/6 options won't induce any lag/delay??

 

 

 

 

 

[Dave m]

if you have just composite now, why do you have a latency problem?

 

Unless you have VERY long runs, there shouldn't be any.

 

as I said, HD-SDI is cheaper than composite - dunno why, possibly due to sheer amount of cable being produced.

Pretty much any conversion process involves latency. It's a matter of how much. I would guess that this is determined by relative cost.

[dosxuk]

The video/cat5 solutions which are just baluns, should have no latency. The ones which convert to other formats, like IP, will have significant amounts.

[sleepytom]

So a few issues (which should be pretty basic video 101 stuff!)

 

Latency.

The latency you see at the moment on your projector is because you have an XGA projector and you are feeding it analog PAL video. This has to be upscaled and deinterlaced before the projector can display it - this typically takes between 3 and 7 frames depending on the model of projector.

 

Quality.

If you only have composite tie line to your projector then your forcing everyone who wants to display graphics to use an extremely poor quality signal type which seriously limits the output quality (and requires a scanconverter to plug their computer into) You should run VGA to the projector as a very bare minimum so that people who have graphics to display from laptops can do so at native resolution.

 

Cable types.

The various RG59 / RG6 et al numberings tell you nothing at all about a cable other than its external jacket size. It is not true that RG59 is not usable with HDSDI nor is it true that RG6 is HD cable! The cheap co-ax that CPC sell is designed for satellite TV installs, it is very far from ideal for either composite video or HDSDI. It's possible that such cable might work OK for shorter distance runs but unless you have a £100000 eyepattern scope you won't actually be able to tell how close to not working your system is.

 

Any touring production using HDSDI (which is actually very common these days) will have their own cables to run in from stage to FOH. I've NEVER found inhouse tie lines which work reliably with HDSDI in ANY venue (I believe the Barbican might now have decent cables installed, they were re doing it last time I was in there) but regional theaters normally have cables which don't work.

 

If this was my installation I would be putting in Cat6 cables, terminating in properly mounted cat6 sockets (ethercon wall plates ideally). I would use passive "muxlab" baluns for composite feeds for inhouse purposes patched into the tie lines with short cat6 patch cables. I would have at least 2 Cat6 lines to each of the projector(s) positions. I would have an active VGA (or DVI if the projectors have DVI inputs) converters (ideally Extron or Kramer or possibly genfen or atlona) for graphics feeds to the projectors.

 

When people start needing HD I would be planning to install HDBaseT converters to work with the Cat6 infrastructure.