have same situ of MP4 inside .AVI, from a helmet cam recording to SD card, and converted them last time using Super IIRC. Just picked more footage from client this weekend, and have to dig up previous workflow. I definitely didn’t use anything expensive last time.
btw, the clips play best inside DivX player – haven’t tried the DivX converter since haven’t got the Pro version, but it’s also a possibility…….