1. A method comprising: towing a seismic source, the seismic source comprising an air gun; towing at least one seismic streamer including seismic sensors; obtaining data indicative of at least one image of a marine seismic source event created by the air gun, the data being acquired by at least one underwater camera; and processing the data to determine an attribute associated with the seismic source event, wherein the seismic source event comprises an air bubble and the processing comprises determining an attribute of the seismic source event based at least in part on a volume of the air bubble.