midifilter.lv2 houses a collection of LV2 plug-ins that let you filter MIDI events.

There are 23 MID event filters that are implements:

• Channel Filter -- discard messages per Channel
• Channel Map -- map any MIDI-channel to another MIDI-channel
• Enforce Scale -- force midi notes on given musical scale
• Eventblocker -- notch style message filter. Suppress specific messages.
• Keyrange -- discard notes-on/off events outside an give range
• Keysplit -- change midi-channel number depending on note (and optionally transpose)
• Mapscale -- flexible 12-tone map
• Chord -- harmonizer - create chords from a single note in a given musical scale
• Delay -- delay MIDI events with optional radomization
• Dup -- unisono - duplicate MIDI events from one channel to another
• Strum -- arpeggio effect intended to simulate strumming a stringed instrument (e.g. guitar)
• Transpose -- chromatic transpose MIDI notes
• Legato -- Hold a note until the next note arrives
• NoSensing -- strip MIDI Active-Sensing events
• NoDup -- MIDI duplicate blocker. Filter out overlapping note on/off and duplicate messages.
• NoteToggle -- toggle notes: play a note to turn it on, play it again to turn it off.
• nTabDelay -- repeat notes N times (incl tempo-ramps -- eurotechno hell yeah)
• Passthru -- no operation, just pass the MIDI event through (example plugin)
• Quantize -- live midi event quantization
• Velocity Randomizer -- randomly change velocity of note-on events
• Sostenuto -- delay note-off messages, emulate a piano sostenuto pedal
• Velocity Range -- filter MIDI note events according to velocity.
• Velocity Scale -- modify note velocity by constant factor and offset