I have read several problems for a long time about wine and pulseaudio in Ubuntu but never understood it clearly. What are the problems or seem to be the problems related to wine and the use by default of pulseaudio in regards to sound in games executed via wine. This affects a whole range of users that use Ubuntu but want to still be able to play specific windows games.
There really isn't much of a problem at all these days.
Applications under Wine only know how to talk to a Windows sound stack, so as with most of the other Windows subsystems, Wine provides this. The problem comes from our sound stack changing significantly in the last decade.
Once upon a time...
... we only had OSS and ALSA. They provide predictable interfaces but they aren't easy to code to. It took ages for the ALSA support to a just works stage but once it was working, it worked pretty well. If you want a stack diagram, it's very simple:
Hardware → ALSA → Application
The main problem with ALSA is it's notoriously finicky if you want more than one thing to play at once. Applications could accidentally lock it from others.
Then PulseAudio got popular.
Suddenly every desktop had this thing called PulseAudio. It was another layer between applications and ALSA to allow for many applications to make noise at once and add features like sound-over-network.
But Wine still only knew how to talk to ALSA, and there was now this PulseAudio thing hogging it right from boot. Wine's audio had to be piped through an ALSA compatibility layer into PulseAudio and then back out to ALSA. The stack shows how horrible this looks:
Hardware → ALSA → PulseAudio → ALSA emulator → Wine/Win32 → Windows app
Additionally the ALSA emulation layer (provided by PulseAudio) wasn't great. It would support a couple of channels and a few recording options but nowhere near as much as the ALSA that PulseAudio itself sat on top of.
The perceived problem was always "the other guys' fault"
Audio in Wine didn't work. With hindsight it's easy to see where the problem really was but there were three opinions at the time that made Wine a real battleground:
And to the present day. Things seem much better, so what happened?
Everybody gave a little.
And while it might seem like it, I doubt that's not the end of this story. There are commercially-supported projects like OpenAL and GStreamer that could really simplify Wine's sound stack as well as providing extra features.
These were both quite popular ideas before MMDevAPI but they've stalled a little since.