Final Fantasy Crystal Chronicles has one of the most memorable soundtracks in all of the Final Fantasy franchise. It's a soundtrack that's still praised today, but putting it together proved to be quite a challenge for the dev team. In an interview with NWR, composer Hidenori Iwasaki discussed the hurdles that needed to be overcome when creating the original soundtrack for the GameCube.
It would be correct to say that there were unused performance phrases rather that lost/unused songs to be precise. Speaking of gaming hardware from the early 2000s, it was common to have 256 KB or 512 KB of memory available for music. When you attempt to sound music within that size, the only approach available is sampling an instrument’s waveform for each music interval (for example, the C and E sounds) and using MIDI for playback. The main programmer on FINAL FANTASY CRYSTAL CHRONICLES was very capable though, and they were able to allocate 2 MB of memory for music (even though that may still be a small amount (laughs)).
That’s when we really thought things through. If we have this much memory to work with, we thought we’d be able to use half (1 MB) in the traditional way, sampling intervals (i.e. C and E) and playing back those sounds using MIDI, and use the other half for sampling the Roba Music Theatre’s performance data by breaking them down and playing them back in phrases. The strategy ended up working, and we were able to achieve music that sounded as though you’re listening to something streamed (like mp3s and wavs). That said, in actuality, the task of putting all live performance data into 1 MB was quite a challenge, and an immense amount of trial and error awaited me; it was as though I was trying to solve a large jigsaw puzzle. Even after other team members went home, I worked into the late hours, chopping up the performance phrases, reusing the same parts, and dropping the sample rate among other things. Somehow, I fit everything within the available memory, but there were some phrases that couldn’t be kept, leaving us no choice but to cut them out. This time, we were able to revive the performance phrases that were originally supposed to be incorporated but ended up going unused.