Ardour's handling of MIDI and how it allows the editing of MIDI data differs in key ways from most other DAWs and MIDI sequencers. Also, unlike its handling of audio data, the editing of MIDI data in Ardour is necessarily destructive by nature.

Key features of Ardour MIDI editing

• All editing is done in-place, in-window; there is no separate piano roll window or pane. Notes are edited right where they appear.
• Editing note information in Ardour occurs in only a single region. There is no way currently to edit note data for multiple regions at the same time; so, for example, notes cannot be selected in several regions at once and then all deleted. However they can they be copied and pasted from one region to another.
• Every MIDI track has its own MIDI port for input; it may have an arbitrary combination of audio and MIDI outputs, depending on the signal processing in the track.
• Full automation for MIDI tracks, integrated with the handling of all MIDI CC data for each track.
• Controllers (CC data) can be set to discrete or continuous modes (the latter will interpolate between control points and send additional data).
• There is a Normal and a Percussive mode for note data editing.
• The visible note range is controlled by a scroomer widget, which is a combination scroll/zoom tool for altering the zoom level and range of visible MIDI data. When in internal edit mode, you can also use scroll operations to adjust the visible range in various ways.