4XM encoder used by some games (Toy Commander, Headhunter, Alone In The 
Dark 4). 

Extremelly slow, even for today's processor, and it's not multithread, 
so you won't get advantage on multicore. 

Potentially you could take advantage of multicore by executing more than 
one instance of the encoder, but it tends to crash this way. 

Good luck with it :) 

I think only the newer version doesn't play well on Dreamcast... but I'm 
including here anyway since it's hard to find, and I'm not sure about 
this information.