QMidi 32-bit (prior to v2.8) relied on Apple’s QuickTime framework to read movie files. On 64-bit systems, Apple replaced QuickTime with the new AVFoundation framework, which supports only a reduced set of modern high-quality video codecs. In OS X Mavericks through macOS Mojave, QMidi could still convert eligible files into a readable format using the "QT Modernizer" Apple tool. Since this tool is no longer available on macOS Catalina, third-party software must be used to "modernize" these videos.
QMidi cannot currently display CDG graphics directly from CD+G disks. You need to "rip" your CD+G disks by using the free CDGBackup software. This operation will extract your tracks as MP3+CDG files, which in turn will be played flawlessly by QMidi.
Be sure to use the right version of QMidi:
If your serial starts with "QMDP", download the PRO version, else download the standard version:
NB: To prevent confusion, be sure to remove the wrong version from your HD before entering the registration code.
Hold down the shift key while launching QMidi to reset all windows positions. See: QMidi Help > Shortcuts.
Starting from version 2.0.4, QMidi allows you to save the DLS synth volume "compensation" (offset) in the music device setup window. You can boost the volume as needed and save your changes by clicking the "Save Preset" button:
(*) On Mountain Lion (10.8), Apple has fixed this bug.