[AG-TECH] Access Grid Hardware/Software Questions

Mon Feb 28 17:52:56 CST 2011

Hello Jonathon,

We've been running Dell T5400 and Dell Precision 490 PC's running WinXP SP3 for a few years.  We've tried both Spectra8 and Osprey 440 capture cards, but have been using Spectra8 most of the time.  AG3.1 worked well with 3 cams (Sony EVI-D100P's) but adding a 4th on the Spectra8 caused black blocks of varying sizes to appear on 1 or 2 of the images. Sometimes these were about 1/10th of the image, other times ups to ½ of the image size. Since we generally only use 3 cams that wasn't a problem.  However with the low res of AG3.1 we were often pleased to use 3 cams so that we didn't need to put very many people on each cam. 2-3 is about the most, as the faces become very much less distinct with more people in each shot.  We did find that using a Belkin S-video to USB adapter gave us noticeably clearer images than composite.  However we have only been able to use one adapter on these Dells.  Adding a 2nd causes one of the adapter images to freeze for 1-2secs about once per minute.  I've tried using different USB ports with no improvement, but haven't tested with a powered USB hub.  However Tim Page at Auckland University Arts runs two Belkin adapters successfully on a Dell but I don't remember which model. He gets no freezes.

Regarding audio:  We use the on-board audio using line input and outputs connected into a Nexia VC on several PC's and Clearone Converge 560's on 4 other PC's.  The on-board audio works well, but there is one aspect which needs to be allowed for:  Most on-board and consumer soundcards can take a maximum input level of about +1-2dBV (about 2Vpeak on many systems) before hitting digital clipping.  That means that if you don't have a peak level meter, then -15dB is about the maximum you can run without hitting digital clipping.
Many of the soundcard manufacturers seem to use people of limited intelligence to design the on-screen controls, and many can be very tedious or frustrating to use.  Some feature "intelligent" configuration such that if you momentarily unplug a connector, everything will be reconfigured to another default. Allow plenty of time in configuration for sorting out the audio!
Regarding Creative: After several emails to creative to find out specs for their various soundcards, I've been told they won't release that info because it is confidential.  Most other manufacturers have no problem displaying the tech specs for their cards, so Creative are totally off my list. Imagine buying a new car and the manufacturer won't tell you how fast it would go or what size engine etc because that was confidential!

On the soundcard subject be aware that many consumer cards have very low gain on mic channels. Of six that I've measured, the gains ranged from 6dB (yes 6dB!) to 40dB, which means they are not suitable for dynamic microphones.  However since most use powered or electret types, that won't be a problem.

We've used both Datapath Vision RGB Pro-02 and E1 capture cards. Both need the phase to be adjusted for each different source to eliminate the rainbow fringing. During testing with AG3.2 last year, we found we could only use one input of the Vision RGB cards, but this may have been corrected in subsequent updates.

There are several aspects of running HD video on AG3.2 which are yet to be clarified. In general terms, since AG only uses a single processor, video processing is likely to overload the system and slow it down when more than a few sources are being displayed.  Hopefully we'll get some detailed results from testing over the next few weeks.

Regards,
Lloyd Pearson
AVCC Operator
University of Otago
Ph +64 3 479 8997
lloyd.pearson at otago.ac.nz<mailto:lloyd.pearson at otago.ac.nz>

From: ag-tech-bounces at lists.mcs.anl.gov<mailto:ag-tech-bounces at lists.mcs.anl.gov> [mailto:ag-tech-bounces at lists.mcs.anl.gov]<mailto:[mailto:ag-tech-bounces at lists.mcs.anl.gov]> On Behalf Of Jonathan Klubek
Sent: Saturday, 26 February 2011 3:30 a.m.
To: ag-tech at lists.mcs.anl.gov<mailto:ag-tech at lists.mcs.anl.gov>
Subject: [AG-TECH] Access Grid Hardware/Software Questions

My group at our university was recently tasked by one of our departments to construct an access grid facility (this facility will also function for other types of conferencing and classroom needs also).  After much reading we have determined many pieces we need to get including things such as several ClearOne, Crestron and Extron products to control the various audio and video pieces ranging from scaling windows on the projectors and switching sources to mixing and cancelling echo on the microphones on the various tables.   The problem we are running into in examining everything is with the access grid machine itself.  We have looked at the technology and many of the pieces of hardware are many years old and we are seeing possible issues with integration as things such as PCI are replaced with PCI-e.

We are looking at going with a Dell Precision workstation T7500 to be the access grid machine and have thought about adding more memory and a second processor to it (remember that it will serve multiple purposes. .  My questions are the following:

1.        I see that the software is listed for Linux, OS X, and Windows.  We most likely will be going with Windows so we can support Microsoft Link also.  This software is listed for Windows XP but does it work with Windows 7 32-bit and 64-bit.  This is extremely important with Windows XP support coming to a close.  Also, with the increased resources we plan to use it may be necessary to use 64-bit to take advantage of things such as 4+ GB of memory.

2.       As mentioned before the technologies listed are out of date.  We are especially seeing this with the video capture cards and audio cards.  I was wondering if the following would be supported:

a.       SoundBlaster X-FI XtremeMusic (D)w/Dolby Digital 5.1 (this was the card option on the Dell) - if not is there a newer card than the one listed that is?  We will of course need to integrate with our other products.

b.      Datapath VisionRGB-E1 PCI-e RGB/DVI capture card

c.       Osprey Osprey-450e PCI-e Analog video capture card

If not we are looking for several recommendations of much newer technology that is supported as we see this to be extremely important.

Jonathan
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