GM256M was made because I was curious about 256 key MIDIs for a long time before I even knew programming. I started development on BPFA and it had 256 key support, but the problem was there were no 256 key MIDIs to actually play. So with the help from Arduano, the creator of MIDIModificationFramework... I made a barebones merger that simply took 128 key MIDIs and converted them into 256 key MIDIs. I eventually got bored of that and rewrote it, and GM256M was born.
• Download the program archive from the releases, and extract it.
• Click the "Choose MIDI" button and select an input MIDI.
• Click the "Save Location" button and select where to save the output, and name it.
• Then simply click "Start Merge"