Get a beep to follow a keypress DURING a movie

Hi,

I have an experiment in which i play a movie which lasts about 15 s or so. At a time of their own choosing during the movie, subjects make a keypress and I record the time of the keypress, with respect to the onset of the movie file. I can do this but already. BUT, in a new version of the experiment, I need to play a beep x hundred milliseconds after the keypress. That is, the beep needs to be locked to the occurence of the keypress, and all the while, the movie has to continue playing for its full 15 s length.

Can DirectRT do this, and if so, how? Thanks

Have you tried following the RT to the movie with a blank ("~") stimulus for 500ms (or whatever) and then the sound file?

Hi

I tried that, and I also tried sending a TTL for 200 ms to create a delay after the keypress. Regardless of whether I insert a ~ for 200 ms or a TTL, the beep only plays after the video has finished playing (i.e., several seconds after i need it to happen).

To reiterate, I have a movie playing, during which subjects press a key whenever they want to. A beep needs to follow the subject's keypress by 200 ms while the movie plays out in full before the next trial starts. Currently, the beep will not play until after the movie ends. I guess i need directrt to be able to simultaneously play a movie and a sound file. This should be possible right?

As a last resort, I was thinking that this may be possible with two computers - i.e., sending a TTL after the keypress to another computer running directrt which, having received the TTL plays a beep 200 ms later. BUT, if possible, i'd like to be able to achieve this with one machine only!

I look forward to your response. Thanks