# Representation: **dur¶

## Humdrum Representation for Duration¶

### REPRESENTATION¶

**dur – duration (time-span) representation

### DESCRIPTION¶

The **dur representation can be used to encode a sequence of time-spans or successive durations. Units may be seconds, minutes, hours, days, months, and/or years.

In the **dur representation, duration information is encoded according to the following basic syntax:

years*/months**/days/hours:minutes:seconds.decimal*

Duration information may be encoded in full, or may consist of isolated elements or parts. The following table shows the most succinct ways of encoding single duration values within **dur:

 .11 11 one-hundredths of a second 11 11 seconds 11: 11 minutes 11:: 11 hours 11/ 11 years /11 11 months //11 11 days

Examples of ***dur** components*

Notice that if a single numerical value appears, it is interpreted as seconds. For example, the data token  32 represents a duration of 32 seconds. If a single value appears followed by a slash, it is interpreted as the number of years; if a single value appears followed by a colon, it is interpreted as the number of minutes. Days and hours require two leading or two trailing delimiters respectively. In general, abbreviated forms of **dur representations tend to favor the two extremes of durations: in seconds and in years.

The data token  1:15:10 represents a duration of one hour fifteen minutes and 10 seconds. It is also possible to encode such durations in seconds alone as in the equivalent –  4510. If only a single colon is encountered, it is presumed to delineate minutes and seconds as in  5:33 (five minutes and 33 seconds).

The data token  53/ means an elapsed duration of 53 years, whereas  /9// means a duration of 9 months. The data token  //730/ means 730 days.

The **dur representation provides a means for representing approximate durations. It also provides a means for representing uncertainty, as well as mechanisms for representing time boundaries (prior to ...; after ...).

If a duration token is preceded by the tilde (~) signifier, the entire data token is taken to be approximate. Hence, the token  ~1/ signifies a duration of about 1 year and the token  ~3 means a duration of about 3 seconds.

If a duration token is preceded by the question mark (?), the duration is taken to be uncertain. Hence, the token  ?3: signifies a duration of perhaps 3 minutes.

The **dur representation does not support the x’ and z’ signifies used by related representations such as **date and **Zeit. However, **dur is able to represent shorter-than (<) and longer-than (>) indications. For example, the data token  <1: means a duration of less than one minute.

Barlines are represented using the “common system” for barlines – see **barlines**.

### FILE TYPE¶

It is recommended that files containing predominantly **dur data should be given names with the distinguishing .dur’ extension.

### SIGNIFIERS¶

The following table summarizes the **dur mappings of signifiers and signifieds.

 0-9 decimal values / years-months, months-days and days-hours delimiter : hours-minutes and minutes-seconds delimiter . fractional second delimiter; null token ? duration uncertain ~ duration approximate < duration shorter than > duration longer than = barlines == double barline

Summary of ***dur** Signifiers*

### EXAMPLES¶

A sample document is given below:

 !! Gustav Holst **dur *M5/4 =1 .3 .3 .3 1 0.5 0.5 1.0 =2 *-

### PERTINENT COMMANDS¶

The following Humdrum command produces **dur data as output:

**dur**

change canonical durations (**recip) to elapsed time in seconds 

The following tandem interpretations can be used in conjunction with **dur:

 MIDI channel *Ch1 meter signatures *M6/8 tempo *MM96.3 timebase *tb32

Tandem interpretations for ***dur***

 barlines, **date, **metpos, **ordo, **recip, **takt, **time, **Zeit`