[AG-TECH] High End Portable Access Grid System

Fred Dech fdech at uchicago.edu
Thu Apr 19 09:41:06 CDT 2007

On Thu, Apr 19, 2007 at 05:44PM, Douglas Kosovic said:
> Fred Dech wrote:
> >It's only 8K on the Macbook Pro.  Not sure about the MacPro.  I don't have
> >one handy.  I assume it's the same.
> >
> >--fred
> >
> >On Tue, Apr 17, 2007 at 01:36PM, Joseph Stone said:
> >>Speaking of all ears, how is the audio quality with the Mac setup?
> >>Is it still limited to 8 K samples / sec? The Accumics do a great job of 
> >>delivering but it gets lost to the lower sampling rate.  We've found that 
> >>to be a drawback for recommending Mac's as a platform for now.
> It's a limitation of the osx audio code in rat, it doesn't matter which Mac 
> model is used. The code needs to be modified to make better use of the 
> features provided by Apple's Core Audio API. If I get a chance, I might 
> look into modifying the code.
> >>On Apr 17, 2007, at 11:52 AM, Fred Dech wrote:
> >>>My biggest disappointment is that the Mac Pro will not tolerate multiple 
> >>>IEEE 1394a DV inputs of the type we had planned (DAC200 DV from  Sony 
> >>>EVI D100 svideo source).  It will handle 2 iSights.  It will handle one 
> >>>DV and one iSight.  But that's it.
> It's been a know limitation with the Quicktime DV Video Digitizer for the 
> last decade, it only supports a single connection, see:
>    http://developer.apple.com/qa/qa2004/qa1365.html
> note: vic uses the Quicktime SequenceGrabber to capture from video 
> digitizers and the IIDC Video Digitizer is used with the Firewire iSight.
Hi Doug.  Thanks. that helps explain the different behavior we were getting
between iSights and DV sources.

> >Video capture cards for a Mac Pro?  I'm all ears.
> There are a number of PCI-e analog video PCI-e capture cards for the 
> MacPro, e.g:
> LFG4 (with 4 x Bt878):
> http://www.activesilicon.co.uk/products_fg_lfg.htm
> http://www.aja.com/html/products_macintosh_kona.html
> I can't say how well they work with vic as I haven't tried them.
I wonder if anyone else on the list has any experience with the LFG4?
The LFG4 is PCI-E, which means it will at least fit in the macpro box which
only has PCI-E slots.  It looks promising as an AG card for the macpro.
And since you've done dev work with it and Aqua and AG it might just be
the clearest multi-source solution out there. 

I've looked at the aja / kona card documentation on and off and those cards
are so specifically tailored toward Mac-only applications and capabilities
such as FCP and Dual-link, etc.,  that I doubt they would be useful as AG
video capture devices.  And the input number and format force you to send
different video formats if you want more than one video source... either that
or generate SDI, which I haven't looked into.

I'm going to contact ActiveSilicon & AJA and see if they can send me
a couple demo cards.


> I have used an older PCI-X  LFG4 in a PowerMac, but can't remember what 
> issues it had, if any. I used the LFG4 to develop and test the NTSC, PAL 
> and SECAM support in aqua AG vic.
> Cheers,
> Doug

More information about the ag-tech mailing list