Millisecond Forums

> I would like to know if it is possible for two videos to be playing at the same time in Inquisit

Yes, it's possible to have two videos displayed concurrently:

<trial mytrial>
/ stimulusframes = [1=left_video, right_video]
...
</trial>

<video left_video>
/ items = ("left.mpg")
/ position = (25%, 50%)
...
</video>

<video right_video>
/ items = ("right.mpg")
/ position = (75%, 50%)
...
</video>

> I would also like to know if it is possible to have a video playing on Inquisit while performing a trial (both tasks on the same
> screen).

You can display the video via the <block>'s /bgstim. It'll be displayed throughout the entire <block> / while the <block> runs its trials. You, however, must make sure that any stimuli displayed by your <trial>s do not overlap with the displayed video.

I am trying to present two videos on either side of the screen and Im having a hard time making them load. Ive tried different formats (settling on .wmv) and even broken up my longer video into chunks so that each file is only about 8-9MB

I have both a fixation (attengetter) at the beginning of each trial and both a pretrialpause and a posttrialpause of 1000ms and only want each movie to play for 5 seconds

At the moment, the first trial will play sometimes but after that I can only hear hte audio and the video freezes every time. 

Anyone have tips on dealing with such a video issue?
thanks
Jenny



<trial socialsocial>
/ stimulusframes= [1=attengetter; 60=movieleft, movieright]
/ pretrialpause=1000
/ posttrialpause=1000
/ timeout = 5000
/ inputdevice = keyboard
/ validresponse = ("e", "i")
/ beginresponseframe=1
</trial>

> At the moment, the first trial will play sometimes but after that I can only hear hte audio and the video freezes every time. 
> Anyone have tips on dealing with such a video issue?

#1: It's possible you are having a codec issue, in which case you can either encode the videos with a different codec or try installing a codec pack on the system (such as K-Lite; www.codecguide.com ).

#2: Your <trial> definition does not seem to make sense if you want the videos to play for 5000ms. You only start playing the videos in the trial's 60th frame. Moreover, /timeout includes /pretrialpause, i.e., there are only 4000ms from the start of the fixation point until the trial enters the /posttrialpause.

ah yes, I was playing with stimulustimes vs stimulusframes to see whether that made a difference to the loading. 

I guess I dont really understand how the timing works re times vs frames

Stimulustimes makes more sense to me. If I want the attengetter to be on for 1000, then the video to play for 5000, would I need to make the timeout 7000 (1000 pre, 1000atten, 5000 video). 

why would you choose stimulusframes vs stimulustimes?

<trial socialsocial>
/ stimulustimes= [1=attengetter; 1000=movieleft, movieright]
/ pretrialpause=1000
/ posttrialpause=1000
/ timeout = 7000
/ inputdevice = keyboard
/ validresponse = ("e", "i")
/ beginresponseframe=1
</trial> 

ill try the codec fix, thanks

> why would you choose stimulusframes vs stimulustimes?

Display frames are what every computer display ultimately works with. The duration of a frame depends on the display's refresh rate. On a display running at 100Hz., a single display frame lasts 10ms. With a display running at 60Hz, a single frame lasts ~16.67ms, and so forth. If you have tasks that require short stimulus-display durations (such as a single frame), it often makes sense to specify things directly in frames.

What you specify in stimulustimes ultimately breaks down to frames as well. Inquisit will pick the display frame that's nearest the time you specified, i.e., if the specified time does not coincide with the start of a display frame, a stimulus will be displayed a little earlier or a little later than the time specified. stimulusframes gives you direct control over what stimulus should be displayed in what ordinal display frame number.