Millisecond Forums

Inquisit crashes with videos

By sdandeneau - 4/28/2016


My script, with videos (.mpg for mac and .wmv for windows) runs fine on MAC (lab and web) but the Windows version crashes on both lab and web when it gets to the part that runs the videos. Help!

p.s. the system wasn't letting me upload the file, so I put the dropbox link to the .zip file. 

Stéphane Dandeneau.
By sdandeneau - 4/28/2016

Additional information which may be useful. The script worked fine in Inquisit 4... with .mpg videos. I have since changed to an <include> script with platform types (with .wmv videos for Windows and .mpg for Mac). This new version still works on Mac but still doesn't on Windows. 
By Dave - 4/28/2016

Inquisit 5 uses a different framework (Windows Media Foundation) under Windows to render videos than Inquisit 4 (DirectShow) does in order to support more and more modern formats. That's part of the reason you are seeing different result under Inquisit 5 vs Inquisit 4.

After doing some more testing using both your videos (WMVs and MPGs) as well as others, it certainly looks like there's a bug in Inquisit 5 involved here. As such, there is no immediate workaround using the existing video files / formats.

However, an option that *should* work immediately is converting your WMVs to animated GIFs (which are also handled by the <video> element). Since Inquisit treats GIFs differently internally (they are not handled through Media Foundation), those will work properly (at least that's what my tests suggest). You can find suitable converters online, e.g. .

Hope this helps.
By sdandeneau - 4/28/2016

OK... we've just spent 10K on upgrading to Inquisit 5 expecting things would continue working like they did in 4.... Can we expect a fix relatively soon? Otherwise I'll have to revert back to V.4 until this is fixed so that we can properly run our studies. 
By sdandeneau - 4/28/2016

Hi again, 

I've tried the animated GIF option - but the gif's run in Inquisit at less then 50% speed, i.e. they are much slower (in the task) than the original gif (when I open the same gif in Quicktime for example). It's as thought Inquisit is running at a much slower frame rate, which slows the "video" down significantly. I need the original speed, can Inquisit run a the normal framerate/speed?
By Dave - 4/28/2016

#1: Of course the video issue will be fixed in (probably) the next update, or if only minor changes to the codebase are required a refresh of the current version. When exactly that will be, I do not know yet, but I expect it to be relatively soon (days, perhaps a week or so, not months).

#2: Animated GIFs consist of a series of frames. Inquisit expands those frames into essentially /stimulusframes and displays them at the system's refresh rate. GIFs allow for specifying a number of parameters, and the speed difference is likely due to the default settings of the converter (e.g. a low frame rate, and a long inter-frame interval). I've converted the videos to GIFs with at 20FPS and a slight speed adjustment to more closely match what the WMVs or MPGs would result in (you can find a converter capable of various adjustments at ). When playing the adjusted GIFs in parallel with the MPGs

<video a>
/ items = ("ManDownErrorVite.gif", "ManDownVite.gif", "ManUpErrorVite.gif", "ManUpVite.gif")
/ position = (25%, 50%)
/ select = sequence

<video b>
/ items = ("ManDownErrorVite.mpg", "ManDownVite.mpg", "ManUpErrorVite.mpg", "ManUpVite.mpg")
/ position = (75%, 50%)
/ select = sequence

<trial mytrial>
/ stimulusframes = [1=a, b]
/ validresponse = (57)

<block myblock>
/ trials = [1-4 = mytrial]

the GIFs and MPGs appear to sync up neatly for me. The GIFs used in the above are attached below. Hope this helps.
By sdandeneau - 5/1/2016


I'm not sure I'm getting the same thing as what you'd describing with the files you sent on my Mac. Here a screen shot of what I get.


p.s. The "add file from computer" functions doesn't work for me - hence why I'm sending dropbox links to files. 

By Dave - 5/1/2016

Thanks for the screen recording. That indeed does not match what I'm seeing at all.

Are you seeing the same slow-down under Windows with those GIFs (without the MPGs playing in parallel) or just on your Mac?

By sdandeneau - 5/2/2016

Hi Dave, 

I'm getting something different on Windows - it looks a lot more like the original mpg - and what you described. Bottom line - GIFs are similar to mpg on Windows, but not on Mac. 

Not sure what to do next. 

By Dave - 5/3/2016

Then keeping with the conditional <include> approach should be a viable option: Under Windows, administer the GIFs (instead of the WMVs); under OSX, keep administering the MPGs as before.