I'm writing an application that uses PortAudio to generate sound. I need to synchronize certain GUI changes with the sound stream. The callback function receives a struct PaStreamCallbackTimeInfo that seems to have the timing information I need, but there's no documentation on what the various fields mean. Through experimentation, I've found that the currentTime field is the time that the callback was called (in retrospect, that seems pretty obvious), but what do the inputBufferAdcTime and outputBufferDacTime fields mean?

(Actually, PortAudio calls the callback fast enough that I could just use the currentTime to get the synchronization close enough, but still... it's the principle of the thing.)

As I was working on another part of my project, I just happened to stumble across the answer. Oh well.

For those of you interested, this page says that inputBufferAdcTime is the time that the first sample of the input buffer was received, and outputBufferDacTime is the time that the first sample of the output buffer will be sent.