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, framesPerSecond. A beat is a single pulse of musical time. Beat time is related to real-time by the tempo, 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.

Index

ClassesProperties

Classes

Position

Class
LabelPosition
Superclass ofRate
Time
In range ofposition

A point in time and/or the speed at which time is passing.

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.

Rate

Class
LabelRate
Subclass ofPosition
In domain ofbeatUnit
beatsPerBar
beatsPerMinute
framesPerSecond
speed

The rate of passage of time.

The rate of passage of time in terms of one unit with respect to another.

Time

Class
LabelTime
Subclass ofPosition
In domain ofbar
barBeat
beat
frame

A point in time in some unit/dimension.

Properties

bar

Property
Labelbar
DomainTime
Rangexsd:long
TypeDatatype Property

A musical bar or measure.

barBeat

Property
Labelbeat within bar
DomainTime
Rangexsd:float
TypeDatatype Property

The beat number within the bar, from 0 to beatsPerBar.

beat

Property
Labelbeat
DomainTime
Rangexsd:double
TypeDatatype Property

The global running beat number.

This is not the beat within a bar like barBeat, but relative to the same origin as bar and monotonically increases unless the transport is repositioned.

beatUnit

Property
Labelbeat unit
DomainRate
Rangexsd:nonNegativeInteger
TypeDatatype Property

The note value that counts as one beat.

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.

beatsPerBar

Property
Labelbeats per bar
DomainRate
Rangexsd:float
TypeDatatype Property

The number of beats in one bar.

beatsPerMinute

Property
Labelbeats per minute
DomainRate
Rangexsd:float
TypeDatatype Property

Tempo in beats per minute.

frame

Property
Labelframe
DomainTime
Rangexsd:long
TypeDatatype Property

A time stamp in audio frames.

framesPerSecond

Property
Labelframes per second
DomainRate
Rangexsd:float
TypeDatatype Property

Frame rate in frames per second.

position

Property
Labelposition
RangePosition
TypeObject Property

A musical position.

speed

Property
Labelspeed
DomainRate
Rangexsd:float
TypeDatatype Property

The rate of the progress of time as a fraction of normal speed.

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.

History

Version 1.6 (2019-02-03)
  • Clarify time:beat origin.
Version 1.4 (2016-07-31)
  • Define LV2_TIME_PREFIX.
Version 1.2 (2012-10-14)
  • Use consistent label style.
Version 1.0 (2012-04-17)
  • Initial release.