A Comparison of Approaches for Synchronizing Events in Video Streams Using Audio

A common scenario found in experimentation is to synchronize events, such as breaks between visual stimulus, with the video record taken of an experiment made of participants as they undertake the task. In our case, we recently synchronized a protocol of stimulus presentations shown on a laptop display, with webcam video made of participants’ (who were two year old children) facial and eye movements as they were shown trials of stimulus containing moving dots (a random dot kinematogram or RDK). The purpose was to assess eye movements in response to these RDK stimulus as a part of a potential neurological assessment for children. The video contained audio signals such as “beeps” and musical interludes that indicated the start and end of trials, thereby providing a convenient opportunity to align these audio events with the timing of known events in the video record.