Is there a way to "crop" bitmap based subtitles? Specifically I have some hdmv/pgs subs that I'd like to crop along with the video they go with, and while I can use a complex filtergraph to crop them, they encode as video, I need them to encode as dvb_subs or something similar.
Currently I can either not touch the pgs subs, and simply pass them through with -c:s copy, or convert them to dvd or dvb subs, but they are the wrong size since I've now changed the video resolution by cropping.
My last resort would be to burn in the subs, then crop the video after that using a filtergraph, but I hate burned in subs unless they're absolutely necessary. Is there a way to crop the subs in order to fit the video?