you are describing a buffer over/under run. jitter is when a stream of serial audio data (such as most external usb/firewire/etc audio interfaces end up receivi

you are describing a buffer over/under run. jitter is when a stream of serial audio data (such as most external usb/firewire/etc audio interfaces end up receiving) is not time-aligning it's frames/samples correctly with the clock of the codec (which should be the master clock) or other situations where the clocking of playback/recording differs from the derived "clock" of the streams boundaries.