Display text (or anything) in front of a video

[David McFarlane]

Mary,

As an exercise, I explored this myself further using some typical 
non-Slide techniques for superimposing (overlaying) visual stimuli in 
E-Prime:  (1) setting the movie/slide object Duration to 0, StopAfter 
to No, and following this with a regular Text object with a limited 
Frame size/position and BackStyle = transparent;  (2) using a normal 
Duration on the movie/slide object, setting PreRelease the at least 
as long as Duration, and following that with inline code to display 
the text (e.g., Text.Draw or Canvas.Text).

In both cases, even though my text by design clearly did *not* go to 
the screen until *after* the movie started, and the movie did 
continue to play, the movie immediately overwrote my text display (I 
was careful to make the text and movie frames overlap in such a way 
that I could still see a portion of the text beyond the edge of the 
movie window).  And when you think about it, this all makes 
sense.  Remember, a movie presents a rapid *sequence* of images, one 
frame at a time.  So if you try to put a static text or image in the 
same space, as soon as the movie moves on to its next frame it *must* 
overwrite your "overlay"!

I do not see any way to overcome this except to edit your overlay 
directly into the movie file (as David V suggest), or to incorporate 
sophisticated on-the-fly video mixing facilities directly into the 
software, much as you might find in a modern television 
studio.  Personally, this goes beyond anything I would ask of 
E-Prime, although for all I know something like MatLab can already do 
this.  Hmm, but if E-Prime would allow playing multiple overlapping 
movies on one Slide then that would itself add a fair degree of 
on-the-fly video mixing...

-- David McFarlane, Professional Faultfinder


>Mary,
>
>The answer by David McFarlane is right* - video stimuli are always 
>displayed in front of anything else while running.
>It seems possible to overlay something else over a video on a Slide 
>or Feedback object, then move the video to the back.  But when the 
>stimuli are displayed the video always plays in front.
>
>I suspect you've discovered the warning message to this effect when 
>trying to send a movie to the back on a slide object: "SlideMovie 
>components selected were sent to back to permit for easier Slide 
>component editing, but at runtime Movie components are always 
>presented on top of all SlideText and SlideImage objects".
>
>One solution could be to edit the video files themselves - this 
>seems like a possibility if the alteration is simple (like a 
>fixation cross at a fixed location in all your video files).
>*except concerning David's disclaimer mentioning the target response 
>times for E-Prime support requests placed online. Based on a handful 
>of online support requests by me and other colleagues in the past 
>month or two, the current queue for first response is about 5 working days.
>
>-david
>>I'm running E-Prime 2.0 Standard, and I've run into a problem with
>>being able to display anything in front of a video.  For example, it
>>would be nice to display a fixation cross in the middle of the screen
>>for the duration of our experiment which contains videos.  It seems
>>that the default is set to make any videos appear on the top of
>>anything else that may be on the MovieDisplay.  Is there a way to push
>>the movie to the back so text can be displayed over it?
>>
>
>
>--
>David Vinson, Ph.D.
>Postdoctoral Researcher
>Cognitive, Perceptual and Brain Sciences Research Department
>University College London
>49 Gordon Square, London, WC1H 0PD
>Tel +44 20 7679 5311   (UCL internal x25311, alternate x28694)
>d.vinson at ucl.ac.uk

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