Digital HD Video Systems

[Ashtech]

I would like to invest this year in a digital video transfer system and have looked at the Extron Foxbox to send video from DVI-D to optical cable then back to DVI-D.  I think this system looks really good and I believe that it is very stable and relatively well priced.  I like the fact that as it is not a direct cable link I wont suffer any power related phase problems on signals.  My main concern is that I dont think the optical cable will last long in the hands of some of our technicians.

 

At the moment the main use for the digital link is to come out of an Extron 408 to a couple of Christie projectors. I realise that this is overkill for us at the moment but next year we will be looking to buy the Diventix 2 so it would be good to have the correct infrastructure in place before we invest in the switcher.

 

Is there a system that is as good and as well priced as the optical solution perhaps over SDI cable that would suit my needs without having the risk of fibre optic cable?  I presume that I can get an output card from the ISS408 on SDI?  and if I were to get the Diventix 2 this would also have such a card?

 

Suggestions of other commonly used systems would be appreciated.

 

 

 

Thanks in Advance

 

 

 

Ash

[Pete McCrea]

If your careful fibre systems can survive rental use. We only let the house staff run it in and out and always take care on the route and pinch points. We are currently using the Kramer Fibre systems, both the separate TX/RX units, and the older all in one solution where the ends are captive.

 

As you mention the SDI alternative is viable. However your more limited to the Output resolutions (certainly on the Barco units) to either 576 (SD resolution) or HD resolutions at 1920x1080. Again the good cable is expensive (about a £1/Meter for something like canford SDV which will give about 300m for SD/SDI signals).

 

We'll continue to run both options, but for Data we'll keep to fibre systems, and when we need long runs, or can scale or output to SD/HD resolutions we'll use SDI.

 

And personally I'd be going down the Barco Screen Pro II route rather than the DiVentix route, but that's because I reckon the scaling is better with the Barco kit....

[Ashtech]

Its the in-house staff taking care of it that worries me most.

 

 

 

So the SDI cable reduces the resolution options I can run on it - is that only with a certain system?.  Certainly for the 1st year before we invest in a Diventix (or Screen pro) we will be running the projectors on standard resolutions 1024x768 or 1280x768 maybe a little more than this on one of our projectors that can do 1080i. Really though I think I would want the flexibility, or at least know what the limitations are in more detail.

 

 

 

When you say that you would use optical for data, is that implying that SDI is more for video? 

[Pete McCrea]

Certainly with the Screen PROII via the Enhanced Output Card (EOC) optional extra, the SDI output is only enabled when video resolutions at either SD or HD are enabled. The EOC card is basically a second scaler in the box, giving a second output on 5 BNC's, and when the right resolution is enabled on the SDI output too. It's ahndy for running a TX of everything to a VT Deck for recording the show, or for native resolutions on Plasmas etc.

 

So if your running to an XGA resolution Projector with inputs to the SPII at XGA and say cameras at PAL, you'd set the main out to XGA resolution, then you'd have to down scale to PAL on the EOC card, then send on SDI to the the projector, then have the projector scale it back up to native for the panel, whilst the main outputs could be running at XGA.

 

SDI (and HD-SDI) Video is governed by the SMPTE Standards, so for a device to output SDI, it will need to adhere to these standards. Because it is a broadcast standard, it will only be pixels spaces equivalent to PAL, NTSC and HD signals that will be output. So I'm more stating that SDI is for video.

 

Fibre is starting to become like CAT5- a versatile infrastructure that people are using for transmission of various signal types. To that end there will be more and more systems appearing on the market that allow transmission of the different signal types over fibre. And depending on what system you choose, will limit your resolutions. Our Kramer kits will support everything up to 1920x1080p, making them very versatile, for use either with the full HD CLM HD8 or the SXGA+ CLM R10.

 

Sorry if I've only served to confuse you...

[Ian H]

Video in the digital age is a joy... no hum or earth problems.

 

We use DVI to ST fiber converters from Think Logical ---- easy to use and robust better than kramer IMHO.

 

Monitors are all run and distributed SDI and converted back to analog using AJA boxes close to each monitor

 

ian

;)

[Ashtech]

Thanks Pete,

 

 

 

Most of that makes sense.  Essentially what you are saying is that fibre optics are potentially more versatile.  When using the SDI essentially I will downscale the resolution which I wont need to do on optics (I think).

 

 

 

Ian - I agree, this is part of the reason of going digital - we quite often work in an exhibition environment and regularly get problems with hums and earth problems on our projections.  It can be really problematic and difficult to locate the source of the problem in that environment.

 

 

 

I guess the question now is which Fibre Optic system is the best for my use?