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Old December 20th, 2004, 08:59 PM   #1
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Wanting to design high definition field capture pc system

I'm looking to build a portable pc system to capture the video signal from any video camera with a component, SDI, etc output.

The system should be able to capture 10bit 4:2:2 HD for 1.5 hours. Captured video would be uploaded to NLE or additional drives as required. Depending on the capture card, I expect the portable system could be used for a variety of alternative imaging systems.

I've seen plenty of atx or micro-atx systems that could achieve it, thou they burn too much power and are too large.

I've also been looking at mini-itx pc systems with a SD/HD SDI capture card and 4 sata raided drives.
The system needs to capture 750 GB at 150MB/sec.

The Commel motherboard LV-672 looks close but needs further investigation.


LV-672 brief specification
2.8GHz~3.6GHz CPU.
400/533MHz DDR2/SDRAM
Intel 915G North Bridge. ICH6R South Bridge
1 x PCI express x16 slot. (x1 compatible)
2 x Sata raid channels @150MB/channel.
2 x 1394 ports
2 x Gigabit Lan

1) Capture Solution 1- PCI-Express port
PCI-express x16 slot will be required for HD SDI capture card.
This port is also compatible with PCI-express x1 cards.
Reports of 3 to 1 port PCI-Express riser cards being developed.
which may accommodate a HD SDI capture card & PCI-Express Raid Controller.

2) Capture Solution 2- ICH6R South Bridge
Combine sata channels to achieve >150MB/sec.
Intel's Matrix raid utility only runs 2 drives per channel and 1 raid 0 volume comprising of 4 drives
Maybe software raid!
General Notes
1) Power Supply
Battery with DC to DC converter will replace mains power supply.
The batteries looked good. Saw interesting ones at:

2) Power consumption
Looking for DC battery under 9Kg to supply ~200watts for 2 hours.
Itx Mobo m/board 2.8GHz w/ 256 Meg memory burns 100watts.
Itx Mobo m/board 3.6GHz w/ 2 Gig memory burns 150watts.
250GB Sata's drives burn 15 Watts running, 40 Watts on powerup.

3) Noise
Drive and fan noise may be a problem. Hoping SDI cable can be quite long.

4) General mini-ITX info can be found here:

Micro-atx could be an interim option while waiting for mini-itx technology to mature.

Suggestion of other motherboards, devices, disk arrays, etc... would be greatly appreciated!

Thank you,

David Farland
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Old December 21st, 2004, 08:37 AM   #2
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David: welcome aboard DVInfo.net! I have moved your thread to
our general forum since much more people see it here and your
question is really about what computer + hardware to get instead
of an alternative imaging method.

Good luck and I hope someone can help you on track!

Rob Lohman, visuar@iname.com
DV Info Wrangler & RED Code Chef

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Old December 21st, 2004, 03:37 PM   #3
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1- Power:
Computers need 12V, 5V, and 3.3V, -12V, -5.5V, and a "power good" voltage.
The power good voltage is sent from the power supply to the motherboard (it needs to be between 4-6V). Without it your motherboard won't turn the computer on.

I'm not sure if you can easily power a computer off a battery. That's something you might want to look into.

You can have a battery to AC/DC inverter to a power supply which converts it back to DC, but that wastes some power. If you have a power generator that may not be so much of a problem.

2- Noise:
silentpcreview.com has lots of good information on building a quiet PC. You likely don't need it super quiet as the location's background noise will overpower the computer noise. You probably should get quiet-ish hard drives and a quiet power supply (such as the Seasonic Super Tornado). Faster spinning drives (10k SCSI, 15k SCSI, 10k SATA) give better sustained transfer rates but are louder.

3- Power draw:
silentpcreview.com also has lots of information on the wattage your components draw, as that affects the cooling necessary (and cooling makes noise). You might want to look into a cooler CPU like the Via ones as you don't need a powerful CPU for capturing.

The motherboard doesn't draw much power, the RAM in your computer draws some power (again, you don't need much), the video card can draw a lot of power, and the hard drives draw power.

A more efficient power supply may help reduce power draw (see silent pc review's review of the seasonic super tornado).
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Old December 21st, 2004, 04:01 PM   #4
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Not that I am into HD capture at present, but on the Power supply front, there are PC power supplies designed to run off a 12V source. They have the same form as a standard mains supply (so they just replace the mains supply), except the simply have 12v and 0v/Gnd connections. They are more efficient than an invertor/mains supply combination (longer battery life, less heat, less cooling required, less noise).

People use them for in-car PCs.
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Old December 22nd, 2004, 02:14 AM   #5
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Thanks for the power ‘bootstrap’ idea and the DC/DC converter tip. Hope the DC converter guys thought of the ‘power good’ signal too. I found a couple of options though I’m sure there’s a million more once a motherboard is chosen.



Found a wicked site http://users.erols.com/chare/elec.htmwhich gives the power consumption of most processors. Nice to see a 486sx= 1W while a P4 2.0 Ghz = 100W.

As you said we don’t need any additional power conversion to drain the battery. At least the batteries shouldn’t cause too much ripple. Don’t know about if the switching circuitry on the DC/DC converter causes noise. Maybe that is the difference between the approaches of either link above. Something that will need to be investigated though. I think investigating the DC power supply is rewarding as it doesn’t matter what system, mobo etc we use, the power supply approach and how light weight, cheap etc can be used for all solutions. I first looked at UPS’s but they were so heavy (mainly lead/zinc) and expensive. I’m hoping all we’ll need is some new technology battery i.e eg, Lithium Polymer that won’t cost too much. The executive summary of this link
seems fine talking about rechargeable lithium batteries rated at 200Wh/kg. Interesting to see present power:weight:cost ratios on this. I can see that Plutonium Isotope generator [PIG] housed in a pelican case sitting too close to the camp fire.
Thank you,
David Farland
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Old December 28th, 2004, 04:12 PM   #6
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Thanks to Brooke Clarke, http://www.PRC68.com for this information on power/weight ratio of rechargeable batteries.
I asked him “What kinds of batteries would drive a PC at 200/300W per hour for 1.5 hours?”

This was his reply:-

For reference the most common military battery is the BA-5590 family. Where the BA-5590 is the bench mark LiSO2 primary and has 170 Watt hours in a package that's 5 x 4.4 x 2.45" and weight 2.25 pounds (about 1 kg). So three of these would provide 510 Watt Hours which is a little more than you are asking for. In each BA-5590 there are two seperate "12 Volt" batteries allowing either a series connection providing "24 Volts" or a parallel connection providing "12 Volts". I have put the voltages in quotes because the actual measured voltage is 15 V or 30 V. This is consistent with an automobile DC power system where when the engine is charging the battery you have just under 15 volts. So as a base line an expensive primary battery that's 5" x 4" x 7.35" weighing 6 3/4 pounds (about 3 kg) will work.

In the forum article you mention using an inverter to get back to 115 VAC, but you should look hard at supplying the DC either directly to the electronics or using a switching mode DC to DC converter to get the needed voltages at the currents required. This would be more efficient.

If you use rechargeable batteries there are many options. The most common are Lead Acid, Ni-Cad, Ni-MH and the newest Li-poly.
Lead acid offers the lowest cost but at the price of high weight and some concern about acid fumes that can destroy electronic circuitry.
The capacity of a lead acid battery is given at the 20 hour rate.

For example, from the first battery on the page you reference, http://www.geocities.com/CapeCanaver...9/battery.html
Volts= 12
Weight (lbs) = 66
20 hour (ah) = 135
Rsrv cpcty= 225
Cost = $85

This battery has a capacity of 12 volts * 135 AH or 1,620 Watt hours which at first glance appears to be way too much.
But note it's at the 20 hour rate, which in this case is 135 / 20 = 6.75 amps. 6.75 Amps * 12 volts is only 81 Watts not the 300 you are looking for.
So to get the 1,620 Watt Hour capacity it would take 4 of these batteries and you could run for 20 hours, but that's longer than you need.

When you discharge a lead acid, and most other battery types, at a rate higher than the specified rate you get less capacity. The manufacturer typically has graphs showing voltage vs time for different discharge rates. So for the battery above a wild guess is that if you discharge it at a 5 hour rate, i.e. at 135 / 5 = 27 amps ( 27 * 12 = 324 Watts) the capacity might be only 33 AH or 404 WH, but this is just a guess, you need to check the graphs.

http://www.batteryspace.com sells Ni-MH "F" cells rated at 12 AH ( or 1.2V * 12 AH = 14.4 WH per battery) so 31 of these would give you about 150 WH of capacity. 31 * 1.2 = 37.2 Volts when flat and about 31 * 1.36 = 42 Volts fresh. This type of battery typically can be discharged at the 1 C rate or 12 Amps. 12 A * 37.2 Volts = 446 Watts. This is nice since you don't need to use parallel strings which can have problems. But you will need a switching power supply to convert this to the voltages that are needed at high powers.

Most laptops now use Li-Ion batteries, but the cheistry is very close to Li-poly.
Li-poly batteries are now being used by the RC airplane people because of their high power to weight ratio and because of the ability of some, but not all, Li-poly batteries to be discharged at up to maybe a 12 C rate. No other battery chemistry will allow this.
This pack has a capacity of 11.1v * 2.150Ah = 23.8 WH so it would take 18 of these 5.5 ounce packs. The total weight would be 6.2 pounds or 2.8 kg. This type battery can be connected in either series or parallel with no problems, but they really do not like to be over discharged or over charged. To prevent this a protection circuit that protects each individual cell is best. See:

The thought occurs to me that you may be able to use a slow CPU that does not draw much current if DMA is used to stream the data between the input and hard drive. All the CPU needs to do is setup the DMA then it's out of the picture. This would eliminate fans and greatly reduce your power requirements.

Hope this is of some help,

Brooke Clarke, N6GCE

w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
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Old December 31st, 2004, 12:50 PM   #7
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DC/DC Converters

Yes, DC/DC converters definitely do throw noise out both ends. Input filtering and output "ripple attenuation" modules are required unless they are built in and one must be very careful about shielding, bypassing, ground loops etc.
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Old January 12th, 2005, 01:40 AM   #8
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Okay, looking at the information Brooke sent I found the following cases:

NiMH 24V 4500mah
8 units of these produce 432 watts/hour for 2 hours
Total weight: 9.7kg
Cost: $540

Li-Ion 14.8 V 2000mah 18650 battery module with Protection IC
29 units of these produce 432 watts/hour for 2 hours
Total weight: 5.7kg
Cost: $864

The Li-Ion is $1 per watt and 150W per kilo which looks okay.

Extract from further email by Brooke Shields…..

“….Be sure to get the manufacturer's data for any battery you are considering so you can see what it will do with your load.
The Amp Hour rating is just a way to get you in the correct neighborhood.

If you are going to build a computer using existing mother boards and I/O cards then pay close attention to the DC input power specs and the number of different voltages needed.
I think it would be much more efficient to use a number of DC to DC converters from the battery bank rather than use a battery to 115 VAC inverter and then a 115 VAC to DC power supply.
Note that DC to DC converters are very similar in concept to AC transformers. The power into the converter will be the power to the load divided by the efficiency of the converter.
The efficiency may vary from 50% to 90+%. But a battery's capacity depends a lot on the current drawn from it.
So if you make the battery pack voltage higher the current drawn from the battery will be lower and it's capacity will go up by more than the ratio of the currents…..”

Okay it’s looking like the solution should be Lithium-Ion as the power to weight and cost is right.

I’m sure there is a lot of companies who have assembled battery arrays but you’ll pay a premium which I guess is okay.

Next I found a great site http://www.batteryuniversity.com/index.htm which gives all the introductory battery information you need to begin looking for the right spec.
I think the best way to design the battery is speak to the technical support dept. of the battery companies and they’ll practically design it for you as they’ve done it hundreds of times.

Not sure if the battery pack should be one say 24volt array going into a atx based DC/DC converter or a series of batteries to serve each atx voltage independently.Not sure how the noisy dc/dc converters actually effect system

Battery should be prebuilt or assembled Lithium-Ion
DC/DC converter (or individual battery packs)
Normal AC/DC ATX supply required when uploading ‘footage’ to editing system
6Kg battery may supply 400w for 2 hours

David Farland
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Old February 2nd, 2005, 02:48 AM   #9
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Okay..been a while!

Have looked at various pre-built battery systems.
things like http://www.swe.com/powrtote.html which I need to investigate. It’ll still need a DC/DC converter.
I’ll post the prices when I dig them up.

One interesting supplier was Ocean-Server at

They build a range of systems from 95 to 6000 watts using their Lithium-Ion batteries.
The Li-ion batteries are 95 watt/hr batteries costing $170 and weighing 1.4lbs /.6kg.
Each 4 or 8 batteries requires a battery controller, i.e. BB-04; MP-04 or MP-08
The battery controllers feed a DC/DC converter (atx voltage output), i.e. DC-023

Solution 1:
4 batteries / BB-04 / DC-023 which gives 177W /12A output @ 2 hours.
Weight: 7 lbs/3kg
Cost = $1K

Solution 2:
6 battery / MP-04 /DC-023 x2 which gives 314W /16A output @ 2hours
Weight : 12lbs/5kg.
Cost = $2K

See link for pretty pictures: http://www.ocean-server.com/download/controller19.pdf

This link, http://www.ocean-server.com/download.html (FAQ's) discusses system drain of various mini-itx, atx systems. It also looks at power consumption of SFF boards.
1) PC104 VIA C3 design, 512MB memory, 2.5" disk drive, running Windows-Pro.
Total power consumption is 14Watts (idle.)
2) VIA EIPA M10000 (1GHz), 2.5" disk, 512MB memory,
Total power consumption is 35Watts with LCD monitor (idle).
3) Intel 845 @ 1.8Ghz motherboard is 53 Watts

Will post more solutions as I find them.

Thank you
David Farland
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Old February 3rd, 2005, 05:35 PM   #10
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How do those "gamer" laptops power those desktop CPU's?

For instance, take at look at the new Boxx laptop.

3.8Ghz P4 with HT???

We're talking a lot of power there, so if they are doing it off a single 6600mAh Li-ION battery, there must be some way for you to do it too.

Does anybody know how these laptops are getting power to those very hungry processors?
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Old February 4th, 2005, 06:46 AM   #11
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Depending of how you use them you mightn't get a hour out of the battery even when they throttle the cpu as heat increases /running off the battery. Whereas I know some people who'll get 4 hours out of a Pentium M motherboard with a 90nm CPU off a 95W battery. But a 3.8 GHz prescott burns like a 3.8GHz prescott!
Lucky we don't need one...

Also found the prices to the SWE batteries:

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Old February 6th, 2005, 01:04 AM   #12
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I'll hazard a guess Jason. The Intel line of desktop CPU's have power asaving features as far as I know, but not as good as a PentM, the laptop circuits also has power saving features. So they can sleep, clock back etc. Laptops have very little battery life, desktop cpu based gaming laptoips would have less, so like desktop replacement laptops, you plug them into the nearest outlet.


<<<-- Originally posted by Jason Rodriguez : How do those "gamer" laptops power those desktop CPU's?

For instance, take at look at the new Boxx laptop.

3.8Ghz P4 with HT???

We're talking a lot of power there, so if they are doing it off a single 6600mAh Li-ION battery, there must be some way for you to do it too.

Does anybody know how these laptops are getting power to those very hungry processors? -->>>
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Old February 18th, 2005, 06:56 PM   #13
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Summary info:
Just to summarise the likely components for portable device.
Presently this is built around Blackmagic's Decklink HD PCI-X /133Mhz capture card but may change in the future. Not sure if EDPIX are coming out with one in a few months. The best scenario will be when Apple go PCI-Express so these capture cards are compatible with the range of SFF pci-express mobos.

i. Micro-atx

http://www.gms4sbc.com/V269_Equinox....h UW SCSI 320)
http://www.gms4sbc.com/C269_Equinox....h UW SCSI 320)

Then you have laptop mobos such as PMC P4 / PCIX 133MHz

For now Decklink HD and Decklink Multibridge as the Multibridge embeds the analogue audio in the HDSDI signal.
Note the multibridge employs a -20db stage for audio so that’s a little problem.I know people who capture audio/tc via Firewire and video via DL.
Kona2 capture pcb is the is the Apple equivalent.

Lithium-Ion Battery packs
http://www.swe.com/powrtote.htmlThese people come out with a range of pelican cased batteries. I’m still getting more detail on these.

Favourite but a little costly

Here are a few ideas thou they change every month
Check here often! http://www.storagereview.com

Seagate Savvio 10K.1 (74 GB Ultra320 SCSI Server Mode)
Maxtor Atlas 10K V (300 GB Ultra320 SCSI
Fujitsu MAT (300 GB Ultra320 SCSI)
Seagate Cheetah 10K.7 (300 GB Ultra320 SCSI Server Mode)

Maxtor MaXLine III 2nd Sample (300 GB SATA)
Seagate Barracuda 7200.7 (200 GB SATA)
Western Digital Caviar WD2500JD (250 GB SATA)

I’d begin looking at these:
HighPoint RocketRAID 1820A
Areca ARC-1120
RAIDCore BC4852
Various Adaptec SCSI Cntrls.
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Old February 18th, 2005, 07:09 PM   #14
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"Not sure if EPIX are coming out with one in a few months."

found at... http://www.epixinc.com/products/index.htm
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Old February 19th, 2005, 03:40 AM   #15
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Good, list. If you want to record this through SDI, HD for Indies is a good information source. The guy is also doing hard drive recording.

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