Would it be possible to make a port of a SMB2J nes rom (NTSC) into PAL so that it will play in the right speed.
With right speed I mean, SMB2J would go in the same speed as in SMB1 (PAL). The same speed of both music and graphics.
Perhaps using a Super Mario Bros. (E) (REVA) [!].nes rom and using the information in it and combine it with Loopys MMC3 hack of Super Mario Bros 2(J) would work?
In theory it can be done. In practice if you have to ask you're probably not ready for such a project. For completeness sake: the eu rom won't do you much good except for maybe the values of which speed mario needs to move at. Iirc super mario bros 2 j uses the scanline counter on the mmc3 for something so you're gonna have to adjust timing on that. Change marios move values (might require some code changes) And the same goes for luigi and every other enemy in the game.
Yeah possible, but not easily. I've always been outright impressed that the PAL version of SMB is sped up. You almost have to code the game with that in mind from the beginning for it to be easy (or at least be smart about handling sprite movements and scrolling). OTOH, for converting a PAL game to NTSC speed, it's not as hard to slow it down (the easy way is just skipping every 6th frame, which is what Nerdtracker 2 does - some stuff sounds slightly better in it's original PAL mode).
Memblers wrote:
I've always been outright impressed that the PAL version of SMB is sped up. You almost have to code the game with that in mind from the beginning for it to be easy
It's "easy" in anything that uses subpixel velocity, which Nintendo platformers had already been using since Balloon Fight.