View Full Version : DV Camera Feasibility

12-08-2003, 08:30 AM
We have an upcoming live production that will not be shot in our studio. The normal studio we use has a house system that cannot be moved. We have used VT in past productions for effects and live playback with the ddr and found it very useful when used as a downstream key from our house system.

Since the house system cannot be moved, we are considering using VT for live switching with either the SX-8 with our house cameras or multiple DV cameras coming in through firewire cards on the computer.

The question is - How feasible is it to run multiple (8) DV cameras from one computer and do live switching? This setup would have mutiple computer monitors to be able to see VT-Vision windows (8 total) for each camera.

Would VT be able to handle 8 DV streams? or, is it realistic to expect a computer to be able to handle 8 DV streams, let alone the Toaster? Would that be too much bandwidth for the computer to handle?

Thank you in advance for your excellent assistance.
Chad Woznick
Video Director - WTBTS (FN)

12-09-2003, 09:30 PM
If I under stand it right in order to use DV Cams you will be encoding and then decoding the 8 cameras. This will take some fast computers.

12-10-2003, 12:01 AM
Hm, one problem is that I don't think you can put up 8 VT-Vision (virtual) monitors for your 8 firewire sources, even with multiple screens. My understanding is that VT-Vision monitors can only be attached to the switcher busses (Program, Preview, Main, Key, DSK), not individual sources. (Someone please correct me if I'm wrong.)

If you were using analog inputs with the SX-8, you could at least bounce the inputs through external monitors if you really need live previews of all your sources simultaneously. You might be able to do the same thing with firewire, but I expect it would take external hardware for each monitor...

I'd go analog with external monitors if you really need to look at all those inputs all the time, or digital if you can deal with a single virtual Preview monitor (you can switch it to any input using the switcher without affecting the main out, that's what it's for). (Sorry I don't have a good feel for your main question, how much of a burden 8 DV inputs would be on the machine.)

Good luck, let us know how it goes. -MG.

12-10-2003, 10:46 AM
For 8DV inputs you will probably need external DV to analog convertors. This may blow your budget. There are a number of lowcost external units (Canopus, ADS, etc). I saw where Safe Harbor has the ADS Pyro A/V Link for about $185: it even has component out or in depending on how you set it. If you go this route; test one unit for quality etc., before buying all eight! (Safe Harbor has 30 day satisfaction guarantee).


12-10-2003, 12:01 PM
acutally your computer would never be decoding 8 streams of dv with toaster 3 it only decodes the video from the dv sources that are on the preview or program busses but it does decoded the audio from all the dv sources but if u werent using the audio from the cameras it wouldnt be a big deal i would still recomend at least dual 2.8xeons with hyperthreading and 2 gigs of ram

12-12-2003, 01:34 PM
The real limitation will likely be the length of DV cabling ... this is the reason most still prefer to use analog for this sort of application...

12-13-2003, 11:34 PM
Steve, out of everyone here you put it right on the money.

Cable lengh limits are the big problem here.

I have only seen a 12 foot firewire cable in my days once and it was custom made.

Most you can usually get is 6-8 feet commercially.

12-14-2003, 08:18 AM
Most you can usually get is 6-8 feet commercially.
Check out Markertek (http://www.markertek.com/MTStore/Store.cfm?Manufacturer=TecNec&main=product.cfm?BaseItem=DV-DV-75) they sell a 164' for $109.
I have never used this myself. Personally, I would connect via Y/C.

12-14-2003, 06:18 PM
Hello WVP were are you in Maryland

12-15-2003, 11:34 AM
Analog will be just fine!

Your cameras will be more limiting than the analog signal.

Be sure to "paint" each camera individually to match either a portable color bar system, or good flesh tones.

We do this all the time.

IEEE 1394 (Firewire (tm)) was never designed to be a long-line signal. It was only meant to be used over very short distances. It is NOT a good choice for live camera work.

I won't go down the 1394 vs. NTSC analog path rant today. (Can I have an Amen Puh-leeze...)

Maybe someday....

12-15-2003, 12:26 PM


12-15-2003, 12:31 PM
Originally posted by djlithium
Steve, out of everyone here you put it right on the money.
Once in a while I stumble on a right answer :)

I know there are ways to extend the length, but I can't think of a good reason to bother, nor to suffer the expense.

12-16-2003, 08:19 AM
Markertek or one of those little black-box makers does make a 1394 equalizing D/A.

Its pricey, and so would be a compliant cable.

Your other choice(s) would be to convert the signal to fiber, or microwave and shoot it back to the switcher that way.

If you do decide to go the 1394-D/A combo, please be sure to put the D/A at the camera end.

That way you're not amplifying a low signal after a long run (and all the noise), but rather are making a stronger source, so the distant end gets a compliant signal (with far less noise and therefore less errors).

This also applies for analog line amps too...

12-16-2003, 08:46 PM
Originally posted by Bushmsn
Hello WVP were are you in Maryland
Gaithersburg / Rockville area

12-17-2003, 08:43 AM
I am in Baltimore. What kind of projects are you doing? Do you work for your self?

12-18-2003, 02:07 PM

Actually, there are cable lengths and methods of extending firewire usuability over longer distances. I can't comment on how this will effect the quality of the signal, but the concept does not seem to different from what is typically done to extend other protocals over longer distances. So we will experiment with these options:

The 1394 Store has lengths that are suitable for camcorder use up to 20 meters (66 ft) for $60.00 each.

Also, firewire repeaters can be obtained for a similar price that are rated for up to 110 meters. These can run with bus speeds of 100 / 200 / 400Mbps according to the specs.

This may open up possibilities for those of you out there who are interested in greater DV camera utilization. We will update you once our tests have been completed.