XX by U&I software is an imperfect tool by the developer of Metasynth that takes a graphic approach to manipulating MIDI. You can select rectangular areas of a piano roll and stretch them along both the pitch and time dimensions, invert or reverse them, conform them to a specific key and scale (within a 12-tone equal tempered paradigm), and perform random transforms (of pitch, velocity, time position and/or duration, with the ability to specify the probability and range of change for each of these parameters). It’s Mac-only, it cost 99 bucks and there’s a demo.
Some negatives:
- Its user interface is like Metasynth’s. Idiosyncratic. To me, completely non-intuitive.
- It tries to be a plugin host, but it’s the worst plugin host I’ve ever seen. It will load up to 48 Audio Units, but if you have more than that, they’re not necessarily the ones you want to use. Some AUs can cause it to crash at startup, apparently those without a Carbon UI. Fortunately you can switch off this feature and use other means to audition your work; You can output each part to a MIDI channel or use provided multisample instruments.
- It sometimes has problems importing MIDI files, which may be caused by issues with the MIDI file’s tempo value.
- It allows certain types of velocity manipulation, but as far as I can tell, it doesn’t actually display note velocity.
