More likely is a specific file-naming trick that lets you use right-to-left writing to make a file look like something it's not. When it's written backwards, you can make iva.scr look like rcs.avi, and the target will just think it's a video file when it's actually an executable. If you're not paying attention, you may not notice that Windows Explorer shows a .avi extension but lists the file as an executable. Hell, if you open the file directly from your torrent app, it may not even list the file type at all. In effect, it's not hiding a payload in a video file, just disguising the payload as a video file.