SRT is obviously a basic subs format. I think that originally it was meant to have only basic formatting and in time developers considered it could also support font change as well. It's just there is nobody to care about writing an updated spec
. So it's up to the player whether to implement the font change tag or not. I just tried PotPlayer and just as MPC-HC it respects font change in SRT and displays the change correctly. It seems that both players consider font change tag
an important addition and a
tag worth having for SRT format.
.
I don't know about any other 'unusual' tags like font size (I've never seen it) but it seems that positioning, even though mentioned in the SRT specs
there, is not supported by MPC-HC or PotPlayer.