Hello
I've installed PTB-3 on one of our lab's computers (didn't uninstall
old PTB 3, just removed from matlab path), and now have the following
problem: with some probability, the calibration routines performed
after each SCREEN('OpenWindow') will fail & the script will abort with
the dreaded ! PTB - ERROR: SYNCHRONIZATION FAILURE ! (more output text
pasted below)
It's only *sometimes* that the calibration measurement loop isn't able
to collect enough valid samples from VBLsync, and the 'OpenWindow'
attempt consequently fails... at other times, the same attempt will
collect plenty of valid samples and the Onscreen window comes up quite
rapidly. Out of 10 attempts to call 'OpenWindow', 4/10 succeeded (i.e.
No fatal PTB Synch Error).
I'm puzzled by a couple of things:
One- Why would the problem with the set-up (whatever it is) manifest
itself inconsistently?
Two- Are these timing checks that PTB-3 manditorily performs making me
aware of a pre-existing synchronization problem, i.e. one that was
present when I was using PTB-2 (but hadn't noticed because I hadn't
checked)?
I have an Pentium 4 CPU 2.4GHz with 512MB of RAM. My video card is a
NVIDIA GeForce4 MX 440 with AGP8X/AGP/SSE2. I've read "help
SyncTrouble" and updated my video card driver (signed 12/2006).
Hardware acceleration is set to Full. I don't think the problem is
related to general system demands, since there are not many background
processes active.
I'd appreciate any advice, Thanks!!
-barbara
PTB-INFO: OpenGL-Renderer is NVIDIA Corporation :: GeForce4 MX 440
with AGP8X/AGP/SSE2 :: 1.5.7
PTB-Info: VBL startline = 768 , VBL Endline = 813
PTB-Info: Measured monitor refresh interval from beamposition =
8.775976 ms [113.947444 Hz].
PTB-Info: Will use beamposition query for accurate Flip time stamping.
PTB-Info: Measured monitor refresh interval from VBLsync = 10.063989
ms [99.364183 Hz]. (44 valid samples taken, stddev=0.338454 ms.)
PTB-Info: Reported monitor refresh interval from operating system =
10.000000 ms [100.000000 Hz].
PTB-Info: Small deviations between reported values are normal and no
reason to worry.
PTB-INFO: Using NVidia's GL_TEXTURE_RECTANGLE_NV extension for
efficient high-performance texture mapping...
WARNING: Couldn't compute a reliable estimate of monitor refresh
interval! Trouble with VBL syncing?!?
----- ! PTB - ERROR: SYNCHRONIZATION FAILURE ! ----
I've installed PTB-3 on one of our lab's computers (didn't uninstall
old PTB 3, just removed from matlab path), and now have the following
problem: with some probability, the calibration routines performed
after each SCREEN('OpenWindow') will fail & the script will abort with
the dreaded ! PTB - ERROR: SYNCHRONIZATION FAILURE ! (more output text
pasted below)
It's only *sometimes* that the calibration measurement loop isn't able
to collect enough valid samples from VBLsync, and the 'OpenWindow'
attempt consequently fails... at other times, the same attempt will
collect plenty of valid samples and the Onscreen window comes up quite
rapidly. Out of 10 attempts to call 'OpenWindow', 4/10 succeeded (i.e.
No fatal PTB Synch Error).
I'm puzzled by a couple of things:
One- Why would the problem with the set-up (whatever it is) manifest
itself inconsistently?
Two- Are these timing checks that PTB-3 manditorily performs making me
aware of a pre-existing synchronization problem, i.e. one that was
present when I was using PTB-2 (but hadn't noticed because I hadn't
checked)?
I have an Pentium 4 CPU 2.4GHz with 512MB of RAM. My video card is a
NVIDIA GeForce4 MX 440 with AGP8X/AGP/SSE2. I've read "help
SyncTrouble" and updated my video card driver (signed 12/2006).
Hardware acceleration is set to Full. I don't think the problem is
related to general system demands, since there are not many background
processes active.
I'd appreciate any advice, Thanks!!
-barbara
PTB-INFO: OpenGL-Renderer is NVIDIA Corporation :: GeForce4 MX 440
with AGP8X/AGP/SSE2 :: 1.5.7
PTB-Info: VBL startline = 768 , VBL Endline = 813
PTB-Info: Measured monitor refresh interval from beamposition =
8.775976 ms [113.947444 Hz].
PTB-Info: Will use beamposition query for accurate Flip time stamping.
PTB-Info: Measured monitor refresh interval from VBLsync = 10.063989
ms [99.364183 Hz]. (44 valid samples taken, stddev=0.338454 ms.)
PTB-Info: Reported monitor refresh interval from operating system =
10.000000 ms [100.000000 Hz].
PTB-Info: Small deviations between reported values are normal and no
reason to worry.
PTB-INFO: Using NVidia's GL_TEXTURE_RECTANGLE_NV extension for
efficient high-performance texture mapping...
WARNING: Couldn't compute a reliable estimate of monitor refresh
interval! Trouble with VBL syncing?!?
----- ! PTB - ERROR: SYNCHRONIZATION FAILURE ! ----