I use VLC for my screencapping, mostly because it's easy to bind a keyboard shortcut to the screenshot command, and because it's got a bunch of tools to control video speed - if you use VLC, View - Advanced Controls will toggle a toolbar with the frame-by-frame button (looks like a | with a play arrow after it), and then I have my toolbars customized to show the step forward/step back buttons and the speed controls so that I can skim through sections easily and then slow down playback on sections I want to cap. Only downside is that I've noticed if you play around with speed too much, sometimes VLC just straight-up hangs, probably due to a memory issue or something.

This is only my second time doing costume analysis for something that was actually physically made (I thought it was the first but I checked my archives and remembered I did the live action version of Saitou from Kenshin :') ) - most of my stuff is animanga so it's like, scraping together what details I can and then figuring out which of those are actually physically possible and which are a fiction of the artist's imagination (and in rare cases, get things where the designer has actually put thought into materials and design details - video game stuff seems to be better about this for some reason). I do kind of want to make YOHE Heipaoshi even though 1) lol obscure and 2) I don't think I could talk my cosplay partner into Kunlun (she is also 6" shorter than me, but that's what lifts are for - we made it work for Saiyuki)