presets
type: Specification
license: isc
name: LV2 Presets
shortdesc: Presets for LV2 plugins.
developer: me
release:
  revision: 2.3
  created: 2012-03-22
  blame: me
  changeset:
    item: Add pset:preset property for describing the preset currently applied to a plugin instance.
release:
  revision: 2.2
  created: 2011-11-21
  file-release: lv2-presets-2.2.tar.bz2
  blame: me
  changeset:
    item: Update packaging.
    item: Improve documentation.
release:
  revision: 2.0
  created: 2010-10-04
  file-release: lv2-presets-2.0.tar.gz
  blame: me
  changeset:
    item: Initial release.
documentation: This extension describes a format for presets (i.e. named sets of control values and possibly other state) for LV2 plugins. The structure of a pset:Preset is deliberately identical to that of an lv2:Plugin, and can be thought of as a plugin template or overlay. For example: @prefix eg: <http://example.org/> . eg:mypreset a pset:Preset ; rdfs:label "One louder" ; pset:appliesTo eg:myplugin ; lv2:port [ lv2:symbol "volume1" ; pset:value 11.0 ] , [ lv2:symbol "volume2" ; pset:value 11.0 ] . Presets may be defined in any bundle, including the plugin's bundle, separate third party preset bundles, or user preset bundles saved by hosts. Since preset data tends to be large, it is recommended that plugins describe presets in a separate file(s) to avoid slowing down hosts. The manifest.ttl of a bundle containing presets should list the presets like so: eg:mypreset a pset:Preset ; pset:appliesTo eg:myplugin ; rdfs:seeAlso <mypreset.ttl> .

LV2 Preset
type: Class
subclass of: PluginBase
subclass of: Restriction
  on property: label
  some values from: string
  comment: A Preset MUST have at least one string rdfs:label.
documentation: A Preset for an LV2 Plugin. A preset can be considered an "overlay" on a Plugin. Rather than attempting to define all valid predicates for a Preset (which is not possible since presets may need to specify values for things defined in other extensions), the presets extension simply provides this class which can be augmented with any data in the exact same fashion as the definition of a Plugin. A Preset SHOULD have at least one pset:appliesTo property. Each Port on a Preset MUST have at least a lv2:symbol property and a pset:value property.

Applies to
type: Property
domain: LV2 Preset
range: Plugin
documentation: Specifies the Plugin(s) a Preset may be applied to. When a Preset applies to a Plugin, that Preset SHOULD have ports for every control port on that plugin, each of which SHOULD have a pset:value property. If the Preset is missing ports, or refers to ports which do not exist on the Plugin, then the host SHOULD apply all the values in the preset that do match the Plugin. The Preset MAY have any other values that should be applied to the Plugin in some way. The host SHOULD simply ignore any values on a Preset it does not understand.

Has value
type: Property
domain: Port
comment: Specifies the value of a Port on some Preset. This property is used in a similar way to e.g. lv2:default.

Preset
type: Property
domain: PluginBase
range: LV2 Preset
documentation: Specifies the preset currently applied to a plugin instance. This property may be useful for saving state, or notifying a plugin instance at run-time about a preset change.