"Enhanced MIDI functionality: ACID 4.0 allows you to display and edit MIDI files in a piano roll format, just like a sequencer. The new MIDI piano roll editor allows you to draw new notes, and makes it easier to graphically edit MIDI parameters. Record MIDI tracks into your ACID project using external MIDI devices, or add events using MIDI step recording. MIDI tracks time stretch perfectly to any tempo, and can be rendered with effects just like audio tracks".
"New - MIDI Piano Roll Editing - ACID PRO 4.0 allows you to create and edit MIDI tracks in a piano roll format, just like a sequencer. The new MIDI piano roll editor allows you to draw new notes, and makes it easier to graphically edit MIDI parameters. Use MIDI Quantizing to align your notes with beats based on the parameters you specify, including start times, and note durations. Select any quantize resolution between whole notes and 64th notes".