>Psychtoolbox>PsychTests

[times, badOut, misses]=CheckFrameTiming([rectSize=128][, scale=1][, dur=30][, thresh=0.05][, runPriority=MaxPriority(‘KbCheck’)][, useWhen=0][,useDrawingFinished=1])

based on FastMaskedNoiseDemo, CheckFrameTiming collects and displays
timing info

rectSize = Size of the generated random noise image: rectSize by rectSize
pixels. This is also the size of the Psychtoolbox noise
texture.

scale = Scalefactor to apply to texture during drawing: E.g. if you’d set
scale = 2, then each noise pixel would be replicated to draw an image
that is twice the width and height of the input noise image. In this
demo, a nearest neighbour filter is applied, i.e., pixels are just
replicated, not bilinearly filtered – Important to preserve statistical
independence of the random pixel values!

dur = seconds to display

thresh = percent deviation to report as a miss (specify 5% as 0.05)

runPriority = the priority at which to run

useWhen = 0 for no when parameter sent to Screen(‘Flip’) (seems to give
better timing. any other value sends lastVbl + .5*ifi

useDrawingFinished = 0 to use Screen(‘DrawingFinished’). mario’s comment
suggets it may slow thigns down, but edf thinks it is supposed to speed
things up and only printing its return value would slow things down.

return vals:
times is a vector of inter-vbl-times as measured by Screen(‘Flip’)
badOut is 3 x N, with one column for each frame whose time deviates by more than thresh % from the ifi
row 1 is the frame number
row 2 is the measured frame time
row 3 is the % deviation from ifi
misses are the frame numbers that Screen(‘Flip’) noticed it missed