Regarding presentation of a video stimulus.


Author
Message
Dave
Dave
Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)
Group: Administrators
Posts: 13K, Visits: 104K
First, I am confused. You posted to the Inquisit 3 forum. Inquisit 3 work on Windows only, i.e. that automatically excludes Macs. Regardless, if you want videos to work reliably across platforms, you ought to make sure you pick a codec that's widely available and compatible. You'll find this covered in the Inquisit 4 documentation topic for the <video> element:

"Note that not all video file containers and codecs are supported on all platforms. To present videos that will work on both Mac and Windows, use the mpg (with mp2 codec) format, or use conditional include elements to select *.wmv versions of your videos on Windows and *.mov versions for Mac."

I cannot speak to the crashes you mention without any further technical details.

Yasen
Yasen
Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)
Group: Forum Members
Posts: 4, Visits: 16
Hi Dave, 

Thank again for helping me! 

The guys you referred me to altered the quota limit and I uploaded the videos (122 MB) and ti's all running. However, it doesn't run on all computers I tried it. I have troubles running it on Mac... Say out of approx. 10 computers - 7 run the script and it's all fine, but for 3 of them it crashes - two are with Mac and one with Windows. Any idea why that might be?! 

I'm planning to send email invitations to participants, so if you have some idea why it might not run, I could advise them... something like "please run this task on a computer with Windows operating system only" or "check this or that before you run the task" or something like that... 

Thanks a lot, Dave! :)

Yasen
Yasen
Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)
Group: Forum Members
Posts: 4, Visits: 16
Thanks a million, Dave!! That really helps!! :)
Dave
Dave
Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)
Group: Administrators
Posts: 13K, Visits: 104K
Let me add a couple more thoughts and clarifications (and apologies for the delayed reply, BTW):

- If you have personal webspace available, it is perfectly possible to host your video file(s) there. Suppose you have the file uploaded to http://mydomain.com/myfiles/myvideo.wmv, then the <video> element in your script should be able to fetch that file like so:

<video myvideo>
/ items = ("http://mydomain.com/myfiles/myvideo.wmv")
[...]
</video>

- If need be, the storage limit applicable to files hosted on the millisecond.com server can be lifted. In that case, contact inquisit<at>millisecond.com or support<at>millisecond.com with your account details.

The general caveat mentioned previously remains, though: A slow or unreliable internet connection can cause unacceptable delay or download failure. Perhaps potential participants can be made explicitly aware of this (i.e. have a little patience while stuff is being downloaded) and discouraged from taking part in case their internet access is low-bandwidth or otherwise somewhat unstable.

Lastly, when working with video files on machines not under your control, make sure your files are encoded using a widely available and deployed codec (more exotic ones may not be available on a given participant's computer). WMV should work on virtually all Windows machines out of the box.

Hope this helps.

Yasen
Yasen
Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)
Group: Forum Members
Posts: 4, Visits: 16
Thanks a lot, Dave! Although that's actually not-so great news for me...  as I just managed to bring it down to 175... But anyways thanks for the info, I'll figure something out! :)

Great job on answering so many questions so quickly btw! :)) 

Dave
Dave
Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)
Group: Administrators
Posts: 13K, Visits: 104K
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.

Yasen
Yasen
Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)Partner Member (676 reputation)
Group: Forum Members
Posts: 4, Visits: 16
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
Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)Supreme Being (1M reputation)
Group: Administrators
Posts: 13K, Visits: 104K

/ 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.


dhanya
dhanya
Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)
Group: Forum Members
Posts: 9, Visits: 1

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>




dhanya
dhanya
Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)Distinguished Member (2.8K reputation)
Group: Forum Members
Posts: 9, Visits: 1

Hi Dave,


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


GO

Merge Selected

Merge into selected topic...



Merge into merge target...



Merge into a specific topic ID...




Reading This Topic

Explore
Messages
Mentions
Search