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Don Hoover
07-22-2005, 12:57 AM
Colleagues,

As promised, my initial posting is noted below, followed by the
responses I received from the biomechanics community. Thanks again to
all who contributed to this dialogue,

Don

Don Hoover, PT, PhD
Assistant Professor
Krannert School of Physical Therapy
University of Indianapolis
1400 East Hanna Avenue
Indianapolis, IN 46227
317-788-3500
dhoover@uindy.edu

Initial posting (July 6 2005):

We have an APAS system and wish to build a deskstop CPU that will allow
us to collect data in real time from either four (4) cameras OR from one
(1) A/D board (never at the same time), giving us a need for a unit with
five (5) open PCI expansion ports. However, many manufacturers have
gone away from CPUs configured with so many open expansion ports. Our
IT consultant on campus has come up with a possible solution using the
newer technology of the PCI express. Consequently, we're very
interested in learning if others have successfully used the PCI express
application to capture with multiple cameras simultaneously with APAS
(or a similarly designed motion analysis system), learing about
potential caveats of this hardware configuration, etc. More technical
specifications are listed below.
The motherboard on this computer has 2 PCI express slots and I have
ordered 2 firewire cards that are built to work with PCI express. These
will support 2 cameras each. There are also regular PCI slots on the
motherboard so the analog card that you get from the company will work
just fine.

PCI will transfer 133 MB/sec from a peripheral device.
PCI express will transfer 250MB/sec from a peripheral device.
The increase in bandwith availability in the PCI express architecture
will allow for 2 cameras to utilize the card without loss of data.

Responses from the field:

Don,

you should try to use DUAL channel Firewire PCI cards. These are normal PCI
(not PCI express) cards with TWO independent IEEE-1394 bus systems on it. In
'device manager' they appear as two Firewire adapters.
This will cut down the number required slots to only two and you will have
no problems in finding motherboards. It will probably be cheaper then the
new PCI express technology, too.
We are using these DUAL channel cards for capturing 6 or more DV cameras
with our motion analysis software TEMPLO and they are fine.

www.contemplas.com/motion_analysis_software.aspx?id=1

I am not too familiar with the APAS system but I do not expect any problems.
We also use a A/D converter at the same time without problems.

The PCI bandwidth is more than enough to handle the data rate of several DV
cameras connected to a single PCI card (e.g. 6 cameras with 3.5 MB/s each
require approx. 20 MB/s. PCI has 133 MB/s).

Most modern DV cameras are 'cooperative', i.e. they can be connected to the
same bus anyway. In this case you do not need a Firewire bus for each
camera.
If you have JVC-9x00 models: They are not cooperative.

Please feel free to contact me if you need further information.

Regards,

Thomas Seeholzer

Contemplas GmbH
+49 (08133) 918295
seeholzer@contemplas.com
www.contemplas.com



Don,

We have been successful capturing not only from dual channel Firewire
boards, but also from four channel boards. These boards have four
separate bus systems (similar to what Thomas Seeholzer mentioned) and
are not 4-Port IEEE 1394 Firewire PCI Cards. (4-channel cards can be
obtained from IOI Technology Corp., www.ioi1394.com.) I am confident
that your problem is not a matter of bus speed, but how the Microsoft
operating system treats the signals.

Regards,

Gary Scheirman, Ph.D.
gary.scheirman@viconpeak.com
Vicon Peak
7388 S. Revere Parkway, Suite 901
Centennial, CO 80112 USA
+1-303-799-8686
www.viconpeak.com


Thomas-

Thanks for the note. Can you send me the model # for those dual channel
Firewire PCI cards? I assume this is different from the multi-port firewire
cards. I have two Canon XL1 and have to use separate firewire cards/bus to
connect both to our PC.

We have a Dell with a P4 motherboard and also have a problem with lack of
PCI slots. I may end up getting a PCIX firewire card to open up another slot
for older devices (ie, Redlake camera) but don't know their compatibility
with our current software.

Arnel

Arnel Aguinaldo, MA, ATC
Director, Center for Human Performance
3020 Children's Way MC 5054
San Diego, CA 92123 USA
(619) 250-0184 - mobile
(858) 966-5424 - office
www.sdchp.com