I watched Mark Wilson's 3-part YT video of his clinic where he discusses stance and stroke mechanics. He video taped a students shot and then played it back using an app that showed the timeline out to at least tenths of a second. His tablet looks like an ipad but I can't find any app that looks like what he used. Does anyone know a good app that will allow moving the timeline slowly? It also allowed he to draw lines to see if the stroke remained straight.