http://www.vimeo.com/7526719

I'm writing an application that will act as a piano roll / musical sequencer. I'd like the application to generate audio by manipulating the sample rate of a specified sound file in order to change pitch.

For things like vibrato or portamento (slides), sample rate would have to be changed rather quickly. With Minim, I've tried using threads to set sample rate when a "playhead" passes certain points (essentially changing sample rate every frame for vibrato and slides). Of course, this maintains no semblance of musicality, the amounts of time for which notes are played are completely arbitrary .. I'm guessing that's just too expensive an operation to be performing every frame.

I'm looking for a good strategy to "buffer" this manipulated sample data, as it seems foolish to try and generate it in "real time". In the future I'd like to do so for multiple tracks. Any guidance on the subject would be appreciated (is Minim the right library to use for this  Should I be writing my own Oscillator that reads ahead from an AudioSample)