Stimuli present in stim folder but not presenting (case 3729)

Hello,

I'm finding that stimuli are randomly not presenting during my experiment. I have confirmed that the images are present in the stim folder, are named and referenced correctly, and do not differ in any way from the other stimuli which are properly presenting. I am at a loss because I have used these stimuli in the past with Direct RT with no problems, but now about 1/3 of the stimuli do not present on the screen.
The images are all:
400x400 (pixels)
16 bit
*.bmp
313 KB

The code used to present them is as follows (excerpt):
1 34 color_encoding redAXE 0 0 1 redAXE 0, 0, 1 2000 * 1 35 fixation fixation 0 0 1 ~+ 0, 0, 1 1000 *
I am at a loss as there seem to be no discernible differences between the images which display and those which do not. Any help would be great!

Are the images that are not appearing always the same ones? If so, could you attach one that works and one that doesn't? Or do all of them sometimes appear, and sometimes not appear?

After checking through everything again, I see that I added a number of images actually were 24 bit. However, the Direct RT manual says that it should be able to work with images of this bit depth. I'm also getting a new error saying that there were technical errors in presenting the stimuli. I checked the TrackPerformance file and see:

Subject 1, 12/2/2012, 1:57:21 PM, v2012.4.155, Initial Display: 1440x900, 32-bit colour, 60hz or 16.67ms/screen
Subject 1, 12/2/2012, 1:57:22 PM, v2012.4.155, Session Display: 1440x900, 16-bit colour, 60hz or 16.67ms/screen
Elapsed Time: -1758ms, block 1, trial 20, stim 3, Error 53, File not found or incompatible stimulus format (e.g., images must be 8-24bit color .bmp) , on line 330, during CreateSurfaces of Form DDFullScreen
Elapsed Time: -1758ms, block 1, trial 20, stim 3, Error 5, Invalid procedure call or argument--may be a problem loading a stimulus due to its format, on line 590, during CreateSurfaces of Form DDFullScreen

I note specifically that the bit depth changes for the session display and wonder if this is why my 24bit images aren't displaying. I can see no way of changing that setting unfortunately. Any advice?

**1.bmp is displaying correctly, Yellowaccordo.bmp is not.

Hi there,

I am having exactly this issue. Can you please tell me what the solutions was?

Thanks so much.
Charmaine

There is something "off" about the file. What editor did you save this in? Just curious because I get different bit counts depending on which program I open it in. I also noticed that it's saved at 73dpi as opposed to the usual 72. Anyways, I tried opening it and simply saving it in Irfanview and it seems to work ok. Irfanview is a great freeware app and seems to straighten out any unusual file formatting issues with images. Can you try the attached "re-saved" version of the image and see if it works ok? I tried it here and that seemed to make the difference.

Should also note that the non-working image was also bigger in file size (~468kb vs 312kb). No idea why as they do both *appear* to be 24-bit bitmaps of equal size which should produce identical file sizes. Strange.

Update: We've recemtly had a second case where some bmps with identical dimsensions had a larger file size. Normally BMP files will have the SAME file size. As with the previous case, a small number of images had been saved as 32-bit BMPs explaining the larger file size. We are going to suggest converting the images to 24-bit or 16-bit color and then re-trying them.