Cool, looking forward to next pv release =) I was thinking, it seems most command line tools which display ETA like wget for example exhibit very simple behavior by default: ETA is displayed every second and average rate used to compute it is simply average rate during last second (hence wild ETA jumps when connection speed varies !)
I guess most people would expect that so it probably makes sense for pv to do this by default also. But it'd certainly be handsome to have other algorithms to choose from for cases where that is ill-suited. So the different patches are not necessarily mutually exclusive, could just add command line options to choose which algorithm to use. Regarding this patch, name for '--rate-window' option isn't great, '--eta-window' would be much better. I'll update my patch on github. Good luck with next pv release !
