Sync video with data
A simple solution could be a blinking LED in the video. If the perspective is static the LED could be in the scene, otherwise some (fixed) position in the frame. You trigger the LED and log this event with the datalogger. Then use something like simpleCV (OpenCV vs. Matlab vs. SimpleCV) to detect the blinking event, thus you know the significat frame numbers. From there you can correlate the video data to the logged data.