NES - Replacing Ultima IV music with songs from Ultima III Exodus

[cospefogo]

Dear friends,

Ultima III Exodus is a game I always loved playing. For me it is one of the best RPGs on NES.
I love Ultima IV too, it's a very well done conversion of the PC classic, however, the music on the NES version is soo annoying most of the time.
The songs have no "spirit"! No mood! In my opinion they did not fit well on the way the game was supposed to be.

So, I have this idea in mind for quite a long time...
Imagine NES Ultima IV with music of NES Ultima III Exodus!

Is this feasible?
Is it a task who a experienced rom hacker could accomplish?

Thanks, guys!
Regards,
Cospefogo.

[Disch]

The answer to "is it possible" or "is it feasible" is almost always "yes"... as long as you are not asking for something that is clearly outside the bounds of the system's capability.

However, the answer to "is it easy" is certainly "no".

Games typically have a "score" assigned to each channel.  The score is basically a sequence of bytes that the music engine steps through... each byte representing a note, rest, or other command (like a command to loop, or to change the volume, etc)

Finding and deciphering the score is no small feat.  There are lots of approaches you can take... from corruption and trial-and-error to disassembling the game code and figuring out how the music engine itself works.

Regardless... to accomplish this... you will have to do find the score data and decipher the format for both games.

If you are extremely lucky... both games will use the same score format AND Ultima 4 has more ROM space set aside for the score.  In which case you'll be able to copy/paste Ultima 3's music into Ultima 4... adjust a few pointers, and you're good to go.

However that is extremely unlikely.  More than likely you'll have to decipher/decode the score for each channel in each song... and then manually "rescore it" to use Ultima 4's score format.

And if there are issues with ROM space you'll have to figure out a way around that (not easy).




So yes.  It can be done.  And yes it is certainly within the capabilities of an experienced hacker.