Regarding presentation of a video stimulus.


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dhanya
dhanya
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Hi Dave, 


Is there any way to repeat the triggers in single trail (which contain 150 repetition of same video stimulus)? 


Dave
Dave
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Suppose your video is 500ms long, then you could go for


/ stimulustimes = [0=myvideo,mytrigger; 500=myvideo,mytrigger; [...]; 75000=myvideo,mytrigger]


However this is wholly impractical. Repetitions won't bee seamless and a single trial may only collect a single response. Otherwise, there is no way.


Dave
Dave
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Also note that you'd have to send additional erase triggers (i.e. set all bits to low) in between presentations in the above, single-trial scenario.


dhanya
dhanya
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Hi Dave, 


Tried what you have given but i am getting only one trigger for the whole stimulus (or trial). My stimulus contain only one trial which contain a video  (duration of which is 1.5 minutes). This video contains 150 repetition of syllable /da/, the duration of which is about 450 ms.  So my task here is, i need to get one trigger each for one repetition of /da/. So totally now i need 150 triggers for each /da/ repetition in a single trail. Is it possible to get triggers for a stimulus like this, also i need not want to take any responses from the subject. Its only electrophysiological measure without any  behiavioral measure.


Thank you in advance........


Dave
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See my previous reply. You need to additionally send another port stimulus between presentations, which resets all bits to zero.


/ stimulustimes = [0=myvideo,mytrigger; 20=bitstolow; 450=myvideo,mytrigger; 470=bitstolow; ... ]


with


<port bitstolow>
/ items = ("00000000")
[...]
</port>


Otherwise the signal will remain raised throughout the trial.


dhanya
dhanya
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Hi Dave,


Thank you very much, it worked well...............


dhanya
dhanya
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Hi Dave,



I am attaching the program which i use for an electrophysiological AV experiment. Now the triggers are coming well, my system hangs or the end frame of my video stays long and  i am not able to interrupt the experiment in between. And everytime  i have to restart my system for next presentation of experiment. can you please help me to get rid of this problem.




<port oddballsignal>


/ port = LPT1


/ subport = data


/ items = ("00000001")


</port>



<port bitstolow>


/ port = LPT1


/ subport = data


/ items = ("00000000")


</port>



<video oddball>


/ items = ("da- da (1000- 350).wmv")


/size = (100%, 100%)


/ volume =100


</video>



<trial oddball>


/ skip = [  if (values.lasttrial == trial.oddball.name) values.skipcount = values.skipcount + 1 else false ]


/ stimulustimes = [350= oddball, oddballsignal; 370=bitstolow; 1350= oddball, oddballsignal; 1370=bitstolow; 2350=oddball, oddballsignal; 2370=bitstolow; 3350=oddball, oddballsignal; 3570=bitstolow; 4350=oddball, oddballsignal; 4370=bitstolow; 5350= oddball, oddballsignal; 5370=bitstolow; 6350= oddball, oddballsignal; 6370=bitstolow; 7350=oddball, oddballsignal; 7370=bitstolow; 8350=oddball, oddballsignal; 8370=bitstolow; 9350=oddball, oddballsignal; 9370=bitstolow; 10350= oddballsignal; 10370= bitstolow; 11350= oddball, oddballsignal; 11370=bitstolow; 12350=oddball, oddballsignal; 12370=bitstolow; 13350=oddball, oddballsignal; 13370=bitstolow; 14350=oddball, oddballsignal; 14370=bitstolow; 15350= oddball, oddballsignal; 15370=bitstolow; 16350= oddball, oddballsignal; 16370=bitstolow; 17350=oddball, oddballsignal; 17370=bitstolow; 18350=oddball, oddballsignal; 18370=bitstolow; 19350=oddball, oddballsignal; 19370=bitstolow; 20350= oddball, oddballsignal; 20370=bitstolow; 21350= oddball, oddballsignal; 21370=bitstolow; 22350=oddball, oddballsignal; 22370=bitstolow; 23350=oddball, oddballsignal; 23370=bitstolow; 24350=oddball, oddballsignal; 24370=bitstolow; 25350= oddball, oddballsignal; 25370=bitstolow; 26350= oddball, oddballsignal; 26370=bitstolow; 27350=oddball, oddballsignal; 27370=bitstolow; 28350=oddball, oddballsignal; 28370=bitstolow; 29350=oddball, oddballsignal; 29370=bitstolow; 30350= oddballsignal; 30370= bitstolow; 31350= oddball, oddballsignal; 31370=bitstolow; 32350=oddball, oddballsignal; 32370=bitstolow; 34350=oddball, oddballsignal; 34370=bitstolow; 35350=oddball, oddballsignal; 35370=bitstolow;36350= oddball, oddballsignal; 36370=bitstolow; 37350= oddball, oddballsignal; 37370=bitstolow; 38350=oddball, oddballsignal; 38370=bitstolow; 39350=oddball, oddballsignal; 39370=bitstolow; 40350=oddball, oddballsignal; 40370=bitstolow; 41350= oddball, oddballsignal; 41370=bitstolow; 42350= oddball, oddballsignal; 42370=bitstolow; 43350=oddball, oddballsignal; 43370=bitstolow; 44350=oddball, oddballsignal; 44370=bitstolow; 45350=oddball, oddballsignal; 45370=bitstolow; 46350= oddball, oddballsignal; 46370=bitstolow; 47350= oddball, oddballsignal; 473370=bitstolow; 48350=oddball, oddballsignal; 48370=bitstolow; 49350=oddball, oddballsignal; 49370=bitstolow; 50350=oddball, oddballsignal; 50370=bitstolow; 51350= oddballsignal; 51370= bitstolow; 52350= oddball, oddballsignal; 52370=bitstolow; 53350=oddball, oddballsignal; 53370=bitstolow; 54350=oddball, oddballsignal; 54370=bitstolow; 55350=oddball, oddballsignal; 55370=bitstolow; 56350= oddball, oddballsignal; 56370=bitstolow; 57350= oddball, oddballsignal; 57370=bitstolow; 58350=oddball, oddballsignal; 58370=bitstolow; 593350=oddball, oddballsignal; 59370=bitstolow; 60350=oddball, oddballsignal; 60370=bitstolow; 61350= oddball, oddballsignal; 61370=bitstolow; 62350= oddball, oddballsignal; 62370=bitstolow; 63350=oddball, oddballsignal; 63370=bitstolow; 64350=oddball, oddballsignal; 64370=bitstolow; 65350=oddball, oddballsignal; 65370=bitstolow; 66350= oddball, oddballsignal; 66370=bitstolow; 67350= oddball, oddballsignal; 67370=bitstolow; 68350=oddball, oddballsignal; 68370=bitstolow; 69350=oddball, oddballsignal; 69370=bitstolow; 70350=oddball, oddballsignal; 70370=bitstolow; 71350= oddballsignal; 71370= bitstolow;72350= oddball, oddballsignal; 72370=bitstolow; 73350=oddball, oddballsignal; 73370=bitstolow; 74350=oddball, oddballsignal; 74370=bitstolow; 75350=oddball, oddballsignal; 75370=bitstolow; 76350= oddball, oddballsignal; 75370=bitstolow; 76350= oddball, oddballsignal; 77370=bitstolow; 78350=oddball, oddballsignal; 78370=bitstolow; 79350=oddball, oddballsignal; 79370=bitstolow; 80350=oddball, oddballsignal; 80370=bitstolow]


/ validresponse = (" ")


/ correctresponse = (" ")


/ trialduration = 500


</trial>



<block oddball>


/ trials = [1 = replace(oddball)]


/ stop = [block.oddball.trialcount > 1]


</block>



<expt oddball>


/ blocks = [1=oddball]


</expt>



*************************************************************************************************


************* GLOBAL SETTINGS AND VARIABLES ******************************************


*************************************************************************************************


<values>


/ lasttrial = ""


/ skipcount = 0


</values>




Dave
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/ trialduration = 500 doesn't make sense. You might also want to set /responsetime = 0, otherwise you may not be able to interrupt the experiment while the stimulus presentation sequence is running.


Yasen
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Hey Guys, 

I'm about to run an online study where part of the stimuli are video files. The question is - is there a limit on the total size of script and stimuli for online studies? 
Mine total is about 175 MB. Would such size be OK or it will cause problems?

Thank you very much in advance! Any help, comment, advice will be greatly appreciated! :)

Cheers, 

Yasen 

Dave
Dave
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Yes, there is a limit (approx. 40MB, I believe) and 175MB is well beyond what can be recommended to ensure an acceptable user-experience for your participants. Keep in mind that -- in order to provide proper stimulus / response timing -- all files an Inquisit experiment relies on must be fully downloaded to each and every participant's computer prior to actually starting the experiment. With a 175MB video file, this process will take rather long and may fail for anyone on a slow and/or unreliable internet connection. You should investigate whether you can get the video down to a more reasonable size via re-encoding.

Hope this helps.

GO

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