[Bug 48781] New: midiOutShortMsg sends more than 2 bytes for Program Change

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=48781

Bug ID: 48781
           Summary: midiOutShortMsg sends more than 2 bytes for Program
                    Change
           Product: Wine
           Version: 5.0-rc6
          Hardware: x86
                OS: Linux
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: winmm&mci
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

According to the Windows multimedia spec of midiOutShortMsg the second pair of
MIDI data bytes are optional, depending on the MIDI status byte. For the MIDI
event Program Change there are no optional data bytes. But midiOutShortMsg for
Program Change sends those optional bytes, too. This results that some modern
keyboards accepts the second byte as a further Program Change which is 0
meaning piano for bank 0. The consequence is that every midi file played by
such an external MIDI device always sounds as piano. According to the Windows
spec "This function - midiOutShortMsg - is used to send any MIDI message except
for system-exclusive or stream messages." - which means for Program Change as
well resulting in that behaviour.

As a workaround midiOutLongMsg was used for Program Change with length = 2.
This avoids sending additional invalid bytes. midiOutShortMsg is very broadly
used according to the Windows spec for Program Change events and should be able
to handle Program Change correctly.