From: Stace Peterson (stacep++at++sgi.com)
Date: 10/25/2005 14:34:54
Hi,
I asked around, and found someone who could give a little bit of
information. His response:
> The two pipes are genlocked. We want to know the time lag
> between the outputs of the master pipe and the slave
> via the DDO2 DVP channels, down to the order of
> nano-seconds.
If you want to know this sort of thing within nano-seconds, it will of
course depend on the length of the wires as well as the impedence of
those same wires. The simple rule is about 8 inches per nano-second,
and there is some additional delay in the electronics on the second
pipe.
So, I guess I'm saying that noone can give you a theoretical answer that
is of much use. To find the actual delay, your best bet is to connect
the sync signals to a two channel oscope and measure it.
There are also variations in components between one DG5 board and
another, so if you simply go measure this on an oscope, you might well
need to recalibrate it if you ever have to replace a DG5 board.
Hope this helps,
Stace
faculaganymede wrote:
>
> Hi Stace,
>
> Thank you for your reply.
>
> Our Performer application is running on a SGI Onyx
> 300, InfiniteReality 3, with 2 graphics pipes. The
> two pipes are genlocked. We want to know the time lag
> between the outputs of the master pipe and the slave
> via the DDO2 DVP channels, down to the order of
> nano-seconds. Our Performer application runs at a
> frame rate of 200 Hz, 12-bit RGB image depth. Do you
> have any info on this, or can point us to someone at
> SGI who may know?
>
> --- Stace Peterson <stacep++at++sgi.com> wrote:
>
> > Hi,
> >
> > The short answer is no, typically there should not
> > be a lag time between
> > pipes. The long answer is, it depends upon your
> > hardware setup and
> > application. With the correct hardware, an
> > application can synchronize
> > the swap behavior of multiple pipes. Are you not
> > seeing synchronization
> > of pipes? If so, what is the application (just
> > perfly?) and hardware
> > setup?
> >
> > Thanks,
> > Stace
> >
> > faculaganymede wrote:
> > >
> > > Performer gurus,
> > >
> > > When using two pipes in a Performer application,
> > is
> > > there a time lag between the outputs of the two
> > > graphics pipes?
> > >
> > > Thanks,
> > > faculaganymede
> > >
> > >
> > >
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> -----------------------------------------------------------------------
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> >
> -----------------------------------------------------------------------
> >
> > --
> >
> ------------------------------------------------------------------
> > Stace Peterson
> > stacep++at++sgi.com
> > Silicon Graphics, Inc.
> > (650) 933-2323
> >
>
> Thanks,
> faculaganymede
>
>
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-- ------------------------------------------------------------------ Stace Peterson stacep++at++sgi.com Silicon Graphics, Inc. (650) 933-2323
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