pcejin is a new project I've been working on that takes the PCE emulation core from Mednafen and gives it a real Windows interface. pcejin's movie format is already accepted by the site because it is the same as the submitted Dracula X movies.
It is sync compatible with Mednafen and is intended to replace it on Windows for PCE TASing. All current movies should sync on pcejin once converted, and new pcejin movies should sync on Mednafen as well.
There is a slight incompatibility with Mednafen mc2 format movies made with a revision prior to 270, since buttons 1 and 2 swapped. Revision 270 of Mednafen, as well as the current version of pcejin have buttons 1 and 2 corrected. To fix a movie, just swap all instances of 1 and 2 in the movie file.
Older Mednafen mcm format movies are not affected by that, and can be converted with an option in the tools menu.
http://code.google.com/p/pcejin/