LV2 Units

This vocabulary defines a number of units for use in audio processing.

For example, to say that a gain port's value is in decibels (db)

@prefix units: <http://lv2plug.in/ns/extensions/units#> .
@prefix eg:    <http://example.org/> .

eg:plugin lv2:port [
    a            lv2:ControlPort , lv2:InputPort ;
    lv2:index    0 ;
    lv2:symbol   "gain" ;
    lv2:name     "gain" ;
    units:unit   units:db
] .

Using the same form, plugins may also specify one-off units inline, to give better display hints to hosts:

eg:plugin lv2:port [
    a            lv2:ControlPort , lv2:InputPort ;
    lv2:index    0 ;
    lv2:symbol   "frob" ;
    lv2:name     "frob level" ;
    units:unit [
        a            units:Unit ;
        rdfs:label   "frobnication" ;
        units:symbol "fr" ;
        units:render "%f f"
    ]
] .

It is also possible to define conversions between various units, which makes it possible for hosts to automatically and generically convert from a given unit to a desired unit. The units defined in this extension include conversion definitions where it makes sense to do so.

Version 5.12 (2019-02-03)

• Fix outdated port description in documentation.
• Remove overly restrictive domain from units:unit.

Version 5.10 (2015-04-07)

• Fix non-existent port type in examples.
• Add lv2:Parameter to domain of units:unit.

Version 5.8 (2012-10-14)

• Remove units:name in favour of rdfs:label.
• Use consistent label style.

Version 5.6 (2012-04-17)

• Add unit for audio frames.
• Add header of URI defines.
• Merge with unified LV2 package.

Version 5.4 (2011-11-21)

• Make units.ttl a valid OWL 2 DL ontology.
• Define used but undefined resources (units:name, units:render, units:symbol, units:Conversion, units:conversion, units:prefixConversion, units:to, and units:factor).
• Update packaging.
• Improve documentation.

Version 5.2 (2010-10-05)

• Add build system (for installation).
• Convert documentation to HTML and use lv2:documentation.

Version 5.0 (2010-10-05)

• Update packaging.
• Improve documentation.
• Initial release.
• Define used but undefined resources (units:name, units:render, units:symbol, units:Conversion, units:conversion, units:prefixConversion, units:to, and units:factor).