Simon Bennett (simonb++at++wormald.com.au)
Thu, 23 Nov 1995 09:32:52 +1100 (EST)
> Our company is currently developing an application using a 3 pipe
> ONYX, using IRIX 5.3 and Performer 1.2. The 3 pipes have been
> genlocked together, both via software (using setmon) and hardware
> (cabling the sync, genlock and swapbuffer ports as described in the
> SGI manuals).
> During the process of testing the different frame rate controls
-- snip --
> the other two will start at different refresh cycles. I have also
> informed Paradigm Simulation of this problem (we are using their Vega
> products), and they could re- create it on their equipment.
>
> Since the draw process does not start at the proper time, the frame
> synchronization does not always take place properly. Example: if
> the frame rate is set for 15 Hz, even though the draw process can run
> well within the frame, the frames will drop to 7.5 to 10 Hz. This
> apparently is because the draw process overruns the frame, because it
> started late.
I've been led to believe that Performer 1.2 did not synchronize the video
clocks on multipipe systems -- and that this has been fixed in 2.0...
We had a similar problem under 1.2 on our 3-pipe Onyx... I could get the
pipes to sync just fine using GL - but no joy under Performer 1.2... :(
> Because of this problem, I find it difficult to write a real-time
> application that will run at the proper frame rate.
I wish this didn't sound familiar! :)
> Has SGI seen
> this problem and if so, is there a fix to the problem ?
2.0?
+----------------------------------------------------------------------------+
Simon Bennett simonb++at++wormald.com.au
Wormald Technology Advanced Systems Engineering Ph: +61 2 9981 0611 (x512)
Meeting - an event where you take minutes and waste hours.
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