Screen('GetFlipInterval')

Psychtoolbox › Screen.{mex*,dll} subfunction

Returns an estimate of the monitor flip interval for the specified onscreen
window."windowPtr" is the handle of the onscreen window for which info should be
returned. "nrSamples" If left out, the estimated interval from previous calls to
GetFlipInterval or from the initial calibration done during
Screen('OpenWindow'...) is reported. If set to a value greater zero, PTB will
perform a measurement loop to compute a good estimate. The loop will run until
at least nrSamples valid samples have been taken and standard deviation of the
measurement is below "stddev" seconds. A timeout value "timeout" can be set to
abort the measurement after timeout seconds if the measurement doesn't converge
for some reason. Timeout is 10 seconds and stddev is 50 microseconds by default.
PTB automatically takes at least 50 valid samples when opening an
onscreen-window, trying to achieve a standard deviation below 100 microseconds,
but timing out after a maximum of 15 seconds. If you require very high
precision, call this routine with values that suit your demands. The returned
monitorRefreshInterval is in seconds, but has sub-millisecond accuracy. The real
number of valid samples taken and the final standard deviation is returned as
well. CAUTION: When using OpenGL flip-frame stereo (stereomode=1 in OpenWindow))
on ATI graphics hardware, the flip interval (as reported here) may be twice as
long as the monitor refresh interval! Using Anti-Aliasing with a high
multiSample level at a high display resolution may also cause the graphics
hardware to switch to a flip-interval twice as long as the monitor refresh
interval, because it is not capable of performing all anti-aliasing computations
in one single refresh interval.

###See also: OpenWindow, Flip, NominalFrameRate