video clips delayed

I want to have subjects respond to video clips. I designed an input file with 15 trials, each having a video clip (1940 ms) as stimulus. response time maximum was set to 3940! ms. trial interval was 500 ms. When I run the complete input file (introduction, 3 examples, 15 video trials), at least 2 or 3 videos were not displayed within the expected time frame. The delay between response of subjects to the trial presented before and those videos are at least 3000-4000 ms!!! All you see is a black screen. The log file, however, shows very short load times for those vids (about 14 - all other trials range from 99 to 115), and the totalInt range from 499 to 501, which seems to me absolutely ok. DirectRT is running on a laptop with dualcore processor and 2 GB working memory with 19" Flatscreen with 60 Hz. Can anybody help me?

Strange. Could you post or send me:

1. your input file
2. a sample log data file

I'll take a look and see what I can come up with. My initial [I]guess[/I] is that DirectRT is not getting enough time to preload the clips. Sounds like you are using a 500ms inter-trial interval, yes? If this is not enough time to load the videos, then they will not be able to play at trial onset. Just out of curiosity--try a trial interval of 1000-2000ms and see if that affects the likelihood of proper display.

Hi jarvis24,

I already solved the problem concerning the video clips: Before running the final input file I made some changes on a few video clips and simply forgot to save the new files in the stim folder (grrr...). Hence, directRT obviously searched for those files in other folders, and that caused the delay! Now everything is fine! Videos running smooth, log-files show no problems!
Thanks for your answer, anyway!

Thanks for the update. Glad to hear all is well again :)

-Blair