Trigging loop out from controller not recognized

[Uwe Klotz]

Very short button presses that result in two "loop_out" events (pressed=true=1 followed by released=false=0) are sometimes not recognized by Mixxx. This only happens for the Loop Out button. I was not able to reproduce it with the Loop In button that is mapped in exactly the same way.

Steps to reproduce:
- Loop is inactive
- Set a loop in point by pressing (and releasing) the corresponding button on a controller
- Set a loop out point by pressing (and instantly releasing) the corresponding button on a controller

Both button press and release events must by captured and the "loop_in" and "loop_out" controls are set accordingly to either 1 (pressed) or 0 (released).

Example: Denon MC6000MK2
https://github.com/mixxxdj/mixxx/pull/1664

[Sean M. Pappalardo (pegasus-renegadetech)]

You verified with --controllerDebug that the MIDI message mapped to loop_out=0 is actually being received by Mixxx, right?

[Uwe Klotz (uklotzde-deactivatedaccount)]

I've checked with a MIDI monitor that even the shortest press/release cycle always sends 2 separate messages.

Unfortunately --controllerDebug is unusable with Qt5, no debug messages are logged. And I had to switch temporarily to Qt5, because with Qt4 Mixxx fails to load the JS scripts on Fedora 28. I've already created another bug report for this (much more serious) issue.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/9290