This paper reports a project conducted in twelve Grade 11 Physics classrooms in Edmonton, Canada, that used close analysis of video recordings of teacher explanations to explore the ways in which physics teachers explain concepts. The focus here is on discussion of the research methods and associated technological and methodological issues rather than on the specific issue of teacher explanations. Details of particular approaches to video analysis, including the qualitative video analysis software packages vPrism and Transana are given, and the costs and advantages of using video data discussed.