record time it took to press a key during video file presentation?

I'm creating a task in which the participant need to stop the video file presented to him whenever he decides to.
Is there a way I can record the exact time it took him to press the key after the video started? (its a short video of 10 seconds, so it needs to be very accurate).

thanks in advance.

Maayan.

Maayan,

A video stimulus presented as a reaction time item (i.e., "rt:" in the time column) will record very precisely the amount of time that has transpired from the beginning of the stimulus, to the time the participant makes the specified keyboard response. At that point, DirectRT will stop the video and move on.

Am I misunderstanding what you're trying to do, or does that answer your question?

[quote=Maayan Nagar;19365]I'm creating a task in which the participant need to stop the video file presented to him whenever he decides to.
Is there a way I can record the exact time it took him to press the key after the video started? (its a short video of 10 seconds, so it needs to be very accurate).

thanks in advance.

Maayan.[/quote]

[LEFT][FONT=Arial][SIZE=2]hi Maayan. What you aim to do is possible, and not much syntax. For example, attached I made a very basic 3-line DirectRT experiment with my own video clip, "vidtest.csv". [SIZE=2]

U[SIZE=2]nder the stim column, the video file needs to beg[SIZE=2]in with an underscore[SIZE=2], [/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/FONT][FONT=Arial][SIZE=2][SIZE=2][SIZE=2][SIZE=2][FONT=Arial][SIZE=2]"_yyy.pin.avi"

[/SIZE][/FONT]However the actual file name itself [SIZE=2]does not [SIZE=2]include the underscore[SIZE=2]--in my stim folder it is simpl[SIZE=2]y called "yyy-pin.avi".[/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/SIZE][/FONT]

Next, the video stim needs to include the desired resolution, in this case, "(640x480)" --the parentheses are needed.

Finally, in your experiment folder where you keep the DirectRT experiment file, such as vidtest.csv, for higher color resolution than 16-bit, make a new text file called "colour.txt" , in which you specify 24 or 32-bit, for color resolution.

More details on such instructions are in the DirectRT manual under "Video / Movie / Animation"

The reaction time for how long it takes a given participant to stop the video will be in the Data folder, in each participant's data file under the column RT.[/LEFT]

I copied this syntax and created a colour.txt file, but I can't get my movie to play. It works in Windows Media Player.

I'm new to DirectRT. I think the problem might be that the software cannot locate my video file. I couldn't find anything in the manual or on the forum that explicitly states how to save files so that the input file can locate and use them (there are references to stim files, but where these are located in relation to the .csv file I'm not sure).

Help would be appreciated!
Sarah

Hi Sarah,

From the Input Files > Stim - Stimulus section of the DirectRT manual:

To define a video or animation in your DirectRT session as a stimulus:
[LEFT][COLOR=#555555][FONT='Verdana']1.[/FONT][/COLOR]Copy the media file to your stim folder (recommended but not necessary)
[COLOR=#555555][FONT='Verdana']2.[/FONT][/COLOR]Enter the name of the media file in a "Stim" cell
[COLOR=#555555][FONT='Verdana']3.[/FONT][/COLOR]Use an underscore "_" to tell DirectRT it's a movie/animation.
[COLOR=#555555][FONT='Verdana']4.[/FONT][/COLOR]Define the size of your video window in parentheses after the file name, e.g., (640x480). DirectRT will play the movie at a size of 640 pixels wide by 480 pixels high. You need to specify the movie size explicitly.[/LEFT]