I'm not much help on knowing how to implement this in Chuck but I am curious what kind of pitch extraction algorithm you intend to use. I've reviewed quite a few but never found one I really liked. It is a tricky problem (What is the difference between a chord and an note from an instrument with harmonics? Theoretically not much.) but based on the number of commercial packages that claim to be doing score extraction I assume there has been some progress since the last time I checked.

-Steve (aka zencuke)

PS. I've looked but I've found very little public documentation for any kind of ChucK extension capabilities whether at the C++ level or ChucK (ChuGin etc.) level. Most of the support focus (documentation etc) seems to be on naive users and/or beginners. That's good but it sort of leaves users trying to do sophisticated things out in the cold. ChucK seems more targeted as a classroom teaching vehicle than as a serious music tool. There doesn't seem to be much interest in developing and supporting a serious ChucK user community. I'm learning that there are quite a few serious users but they mostly seem to work in isolation. I like ChucK but I'm thinking of switching to SuperCollider for serious work and only using ChucK for quick simple experiments. The SuperCollider community seems to encourage serious users. At least the advanced interfaces are documented.