Hi-- I think I have finally found a way to make this work, but I need to verify that DRT can handle this accurately. The first step is to get the exact time I need the TTL to be inserted in the movie, starting from the movie onset. Once I know this time, I can manually add a trigger code into my EEG program. So, for example, if I need a TTL of "101" at 5.987 after the onset of a specific movie with TTL code "100," I will simply add this TTL whenever I see a trigger code of 100. I think this is straightforward. The only way to make this work, though, is if I know the TTL that is sent at the onset of the movie (something I can now do with DRT) is accurately timed. That is, this solution will be screwed up if, for example, the TTL is sent and then the movie plays after a few hundred milliseconds because of processing delays. Can you please confirm that a TTL set at the onset of an .avi file will indeed be sent at time 0 of the movie. Do I need to make sure the movie is under a certain file size to ensure this will happen?