been trying to get VobSub (bitmap) subs working in mkv container with ffdshow-tryout latest build (3342) - using Haali and ZoomPlayer 7
it works - after a fashion - but there are some bugs, the most important of which seems to be that the subs only render for a while, then just stop appearing!!
this was a film I encoded myself from BD original, using BDSup2Sub as tool to convert BD subs into VobSub format
...sub bitmaps are maintained at original AR/size, 1920x1080
the mkv (with embedded subs) works just fine using Gabest VobSub DS Filter
I've seen at least one other report of this problem here:-
one other point of note, choosing swscaler gaussian smoothing method makes ZP crash whenever a sub is attemptedly rendered
I can provide the subtitle stream if it will help in debugging this