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Effects Units based on existing LADSPA integration (GSoC 2010 project)

  • Student: Bruno Buccolo
    • Email:
    • Freenode: Buccolo
    • Skype: bruno.buccolo
  • Mentor: Russell Ryan


Sometimes playing the right tracks at the right time in a perfect mix is not enough. Users like to use effects/filters in their mix to squeeze every bit of energy of a track, make creative mixes using filters, delay beats to get funky, use reverb on vocals to fill the room and so on. Mixxx can already host LADSPA plugins, however it lacks a user interface for proper configuration since there must be a mapping between Mixxx controls and LADSPA plugins.

I'm proposing not only designing a user interface for configuration of LADSPA plugins, but also taking the effects on Mixxx to a whole new level. I'll create Effects Units, that will have standard controls, so we only have to map MIDI once, and then plug-in the desired effect in the effect unit to use them. The user will also have the flexibility to choose how he's going to use these 2 effects units, being able to use both on a channel, a unit per channel or even both on master.



Effects Units

  • Two independent Effects Units for Mixxx
  • An Effect Unit will be loaded with the desired LADSPA Plugin
  • The input of a Effect Unit will be Channel 1, Channel 2 or Both
  • Effects Chaining should be possible (One Channel as input for two Effects Units)
  • An Effect Unit will have 4 Parameters and Wet&Dry that will correpond to the mapped ports of the LADSPA Plugin
  • All controls for the Effects Units can be MIDI Mapped
  • Abstraction of effects backend (ladspa only, for now)

Configuration Dialog

  • Mapping of LADSPA Plugin's control ports to Effects Units parameters
  • Selection of plugin's Wet/Dry control port
  • Value range for control ports (Min ~ Max, Default)
  • Adding custom plugins downloaded from the internet (place on LADSPA_PATH?)
  • Save/Load Configuration


Effects Units

  • Code: Define code architecture
  • Code: Think about data structures to use
  • Code: Design uml diagram for the code architecture
  • Code: Backend abstraction layer
  • Code: Ladspa ←→ Effects Unit connector
  • Code: Enabling MIDI Mapping of Effects Units
  • Code: Study how to choose input for effects
  • GUI: Basic tab view for development only.
  • GUI: Display combobox with available effects
  • GUI: Load port names for the selected effect
  • GUI: RFC on Mockup Effects Units

Configuration Dialog

  • Code: Think about xml structure to save the presets
  • Code: Implement Load/Save xml
  • Code: Adding custom paths to plugins (really necessary?)
  • GUI: Basic preferences panel dialog
  • GUI: Load available LADSA Plugins into list
  • GUI: Load LADSPA Plugin's port names into combo boxes
  • GUI: Min, Max, Default values for each control port
  • GUI: RFC on Mockup Configuration Dialog


  • Select standard Plugins to be shipped
  • Create good presets for them
  • Carefully study how to give instructions for the


Translations of this page:
gsoc2010_effects_units.txt · Last modified: 2010/06/23 12:34 by buccolo