SDI video distribution vs RGBHV

[samsc]

CAT5 UTP cable is not screened, but CAT5 STP is. But you know that.These adapters are designed to be good for runs up to 250m. But obviously they can be affected by 'atmospherics' as can any signal cable

Nev.

there are many levels of things that need to be checked -
there is the signal, the protocol, the connector, the cable.

For example you cannot run cat5 Gigabit 1000BASE-T ethernet to 250m- whatever kindof cable - because of the way ethernet works - not the cable.
its the time delay associated with packets.
that's not a transmission line problem.

[jasonrudolph]

I would also highly suggest getting fiber installed. Especially where it's an installation and you don't have to worry about the fiber getting broken, etc.

With fiber, you can get whatever transmitters/receivers you want. So, you can go SDI, HD-SDI, DVI, Analogue, etc.

RGBHV is very much NOT the way to go I would say. Hum, more prone to failure on a single connector, etc.

The video over cat 5 boxes have the problem that they are just using cat 5 cable, they are NOT doing this over ethernet, so it will not work with ethernet devices (hubs, switches, repeaters, etc) Though I don't know of the new one Nev mentioned, as of yet I have not seen one capable of using ethernet for transmission. The other caveat with these boxes is that while they say they can do up to 1920x1080 (example) resolution, their distance at that resolution is much shorter than what they say is their max distance. The max distance on the product listed is normally at the lowest res the box can run at.

One of the benefits to SDI/HD-SDI is that since it is a broadcast standard, the equipment is going to be around for a while. Unlike computer technology, which is in a constant state of flux, the broadcast world stays much more stable, as the level of investment, etc is much higher. People don't change out $100,000 switchers every couple of years. Computers on the other hand change very frequently. It was HD-15/RGBHV, then DVI, now we have HDMI as well, and now the new "Display Connector" is starting to appear.

That is why fiber gives you the most flexibility. Its probably cheaper to install than the SDI route would have cost. And since it is just the transmission medium, you can make it send and receive whatever it is that you need. You can even change it based on the needs of the show coming in.

[kmclights]

OK, lots of stuff to think about. Thanks. However, nobody has answered the question about the usefulness of SDI/HD-SDI with Catalyst. Is it possible and/ or desirable to output SDI from Catalyst in a theatre environment? Is the quality better/worse than DVI via RGBHV and Triple Head-2-Go?

Also, can HD-SDI be transmitted over the same cable as SDI? From what Richard says above, it sounds like HD-SDI will require a different cable and won't transmit nearly as far.

Sounds like fibre is my best option. Any drawbacks to permanently installed fibre that I should know about? Is the cost of the DVI to fibre codecs significantly more expensive than RGBHV DAs?

Just heard back that they are now proposing a RGBHV network and also pulling some fibre to a few key points, similar to what is happening with the Sound install. I'm just wondering if we need RGBHV at all now. Esp considering the manual patch bay will be RGBHV. Why not just make a fibre patch bay and be done with it? Or, if we can afford it, a digital fibre switching matrix.

Thanks again,

[tharding]

OK, lots of stuff to think about. Thanks. However, nobody has answered the question about the usefulness of SDI/HD-SDI with Catalyst. Is it possible and/ or desirable to output SDI from Catalyst in a theatre environment? Is the quality better/worse than DVI via RGBHV and Triple Head-2-Go?

This can be very subjective. It depends whether you are projecting or using something else. What is the final resolution at the destination? What is it you want to display?

If you are playing back Standard definition clips then SDI will look great but if you want detailed graphics, logos or photos you might be dissapointed with the result compared to the computer screen.

HD SDI on the other hand will give you great resolution but will need a display capable of receiving the signal to reap the benefits.

You also need various boxes (none of them cheap) to convert the signal from the Graphics Card for either SDI or HD SDI

There are so many variables that it is hard to give the definitive answer. You have to look at the whole system and work out what will suffice the highest percentage of the time.

Cheers

Toby