A vocabulary for describing musical time.
This is a vocabulary for describing a position in time and the speed of time passage, in both real and musical terms. In addition to real time (based on 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.
A point in time and/or the speed at which time is passing. A position is both a point and a speed, which precisely defines a time within a timeline.
The rate of passage of time in terms of one unit with respect to another.
This is not the beat within a bar like time:barBeat, but relative to the same origin as time:bar and monotonically increases unless the transport is repositioned.
Beat unit, the note value that counts as one beat. This is the bottom number in a time signature: 2 for half note, 4 for quarter note, and so on.
The rate of the progress of time as a fraction of normal speed. For example, a rate of 0.0 is stopped, 1.0 is rolling at normal speed, 0.5 is rolling at half speed, -1.0 is reverse, and so on.