[Bug 52202] Wine doesn't output any sound when using winecoreaudio.drv

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=52202

--- Comment #4 from Reinhold  ---
For the testing I used the Mac builds of Gcenx. See 
https://github.com/Gcenx/macOS_Wine_builds

After verbose testing of Wine-6.23 on Catalina and Mojave I come to the
conclusion that there is something broken in Wine-6.23 package regarding the
audio output on macOS. In 10:1 cases there is no sound. The issue does not
exist on Linux. On Linux Ubuntu Wine-6.23 is OK and the sound is perfect. On
Catalina (2 installations) and Mojave I compared Wine-6.23 with the previous
versions of Wine-6.19 to Wine-6.22. All previous versions are OK. But when
updating or in a fresh installation of Wine-6.23, there is no sound in 10:1
cases.

I have done the testing with our software from 
https://www.notation.com/Player.php
which is a MIDI player which uses the fluidsynth libraries for audio output
(see https://www.fluidsynth.org/). When switching the MIDI Player to forward
the MIDI output to the Coreaudio MIDI engine of a Mac, the sound is OK.

Therefore I conclude there is something broken on the MAC Wine-6.23 package for
audio output.

In a discussion with Gcenx we identified the changes in winecoreaudio.drv which
were done beginning with the commit 75b57ea13de48994d29401afebbbe534cd503b86
may cause the regression.

In order to demontrate the problem on Catalina I used 2 Wine bottles for
Wine-6.22 and Wine-6.23. Both are identical except for the Wine version. I ran
the same the audio playback song on both Wine bottles.

To reproduce the problem

(1) Download Notation Player 4 from https://www.notation.com/Player.php
(2) Install it
(3) Start it and open a MIDI File through the link on the front page "OPEN A
MIDI OR .NOT FILE"
(4) Play the opened song

PROBLEM:
On Wine-6.22 the sound is OK, on Wine-6.23 there is no sound

Please find attached 2 files with the terminal output
(1) LOG_Wine-6_22.txt, sound is OK here
(2) LOG_Wine-6_23.txt, no sound. In LOG_Wine-6_23.txt at the end of the file I
cut down the number of messages
fluidsynth: warning: Ringbuffer full, try increasing polyphony!
to a few because there happen on and on. .

I looked into the fluidsynth code (I am not an expert here) but that looks as
if the ringbuffer for audio output is not properly managed by the driver side.
We use fluidsynth 2.1.0 which isn't the latest but have many thousends of
installations on various platforms at thousends of users. With these findings I
conclude that the issue is probably a regression in winecoreaudio.drv.

I have not tested other audio players but they probably behave the same.

The comment about winecfg I do not understand because winecfg is not an audio
player.