TTL insertaion

[mickeyi]

OK. Let me see if I understand the logic. Let's say I want to show a 15 second movie, and I want a TTL sent at 9.8 seconds. To do this I would show the movie with a time of 0, and then send an empty stim with a time value of 9800 (the movie will still show because we didn't clear the previous screen, right?), ans then send a TTL at port 888 for say 5ms. Is this right? Also, will the movie play till the end of the 15 ms?

Thanks!

[jarvis24]

Yes, I expect that is how it would play out.

[obhi_lab]

Hi. I discovered this thread while working on the same problem: trying to send a TTL during the display of a movie (.avi) stimulus----e.g., the movie we wish to display is about 6 seconds long and we wish to deliver a TTL to an external device during this 6-second clip. I've tried the suggested work-around but (a) the movie gets cut short or doesn't play at all and (b) the TTL is not successful... advice? thx in advance!
cheers

[jarvis24]

Thanks for the info--would you mind posting your input file so I can try running it here? Please zip and attach any necessary files to replicate the problem.

[mickeyi]

I have finally come around to trying this, and it didn't work for me either. It seems like the empty stim (~) is replacing the video so that the video only shows for a short period of time (a few milliseconds). I haven't yet tested whether the TTL will send (I'm not at my EEG machine right now). Obviously this won't for me. I've attached the file and I used as an example. I'd appreciate your help with this as soon as you can--I thought this work-around was going to work and we're setting to start running our study soon. Yikes!

[jarvis24]

Can you attach the input and style files also--I'm just seeing the video and an instructional text file in the zip. Also, can you confirm the version of DirectRT and Windows that you are using? Another helpful test would be to run the identical input file but using a another text stimulus in place of the movie. e.g., ~text1 then ~text2 sort of thing. Would be useful to know if it's a problem specific to videos or if the initial text would also disappear.

[mickeyi]

Not sure what happened there; I thought I attached everything. I've now attached the input file, a stim folder (with instructions and .avi file), and the style file.

I'm using the latest V2006 version (2.0.28). I also tried using a ~text and it seemed to work, so perhaps this is something specific to .avi files (I've also attached the test with a text file). Please have a look and let me know.