Thank you for your message.
> 1. The ability to change the background color (unless this is already possible?)
Another user requested the same feature.
I released the temporary version of MIDITrail for Mac OS X.
Ticket [#27988] Piano Roll Rain RANGE
http://sourceforge.jp/ticket/browse.php?group_id=5114&tid=27988
In the next version (1.2.1), MIDITrail will include that feature formally.
> 2. 16x anti-alaising (8x still looks pretty jagged)
MIDITrail supports max 16x anti-aliasing.
But if your PC does not support 16x, you can not select 16x.
Please check the spec of the graphic card.
> 3. The ability to output the visualization as a series of .png or similar for high quality video capture.
Sorry, there are no plans to implementing that feature.
I will register your request to the ticket.
Reply to #65329