Sequencer tracks can be edited in a wide variety of manners. For example, one may select a recorded area and transpose it, shorten its rhythmic durations, and have a smooth increment of velocity for a crescendo. Since MIDI's numerical structure makes rapid musical operations quite simple, many compositional techniques, such as inversion, retrograde, rhythmic diminution or augmentation, are often included as editing features. Tracks or portions of tracks also may be looped to create continuous ostinato patterns. Recently, the capability to edit metronomic tempi has been added to many sequencers.
Composers can now specify smooth accelerandos or ritards from one measure to another.
MAX patches usually take real-time MIDI input, process the information according to the composer's specifications and output what could be a very sophisticated set of responses to MIDI instruments. MAX objects simplify the programming tasks of parsing MIDI data and timing events or performing musical and temporal calculations. The user can, if he chooses, also program objects to be added to an already extensive library. Other interactive software applications, such as Intelligent Music's M , allow the performer to program certain boundaries or parameters of response by the computer. MIDI input then triggers an algorithmic set of MIDI-out responses.