This is a vocabulary for precisely describing a position in time and the passage of time itself, in both real and musical terms.
In addition to real time (e.g. seconds), two units of time are used:
frames
and beats
. A frame is a numbered quantum of time. Frame
time is related to real-time by the frame rate
or sample rate
,
time:framesPerSecond. A beat is a single pulse of musical time. Beat time is
related to real-time by the tempo
, time:beatsPerMinute.
Musical time additionally has a meter
which describes passage of time
in terms of musical bars
. A bar is a higher level grouping of beats.
The meter describes how many beats are in one bar.