Basic audio not working

[lawnjelly]

Godot version

3.5 RC 7 (and all other 3.5 official builds)

System information

Linux Mint 20, PulseAudio

Issue description

A simple project to play audio that worked in 3.4.4 and earlier now fails to make any audio.

Steps to reproduce

Add an AudioStreamPlayer with a sound, set it to autoplay.
Run the project - no sound output.
Load the same project in 3.4, sound is output.

Minimal reproduction project

AudioThrottleTest.zip

Discussion

I'm hoping this is something simple, some change to default behaviour.. 🤔

[lawnjelly]

Have bisected to this PR: #54654
This explains why others weren't reporting this - it seems unique to PulseAudio, and might be a problem with the name constructed on my machine.

[lawnjelly]

On further investigation it is very strange, it may be a PulseAudio bug or me misclicking something.
The problem is that the running project is being wired to the wrong audio output:

[lawnjelly]

Ok panic over, have worked out why this was occurring, it is a PulseAudio "quirk" / bug rather than a Godot bug.

My system has 2 audio outputs, speakers, and Yeti microphone output (with no speakers). When I reboot, PulseAudio always selects Yeti as default output, so I have to manually reset it when using audio apps. On this occasion, I created a new project before resetting the default, and PulseAudio associates the program name with Yeti output.

Before 3.5, the name was always "Godot" for PulseAudio, so it presumably would always use the same output, the speakers!

So I'll chalk this down to a PulseAudio problem and see if I can figure a way around this on my system.
Sorry for the panic! 😀

Just for reference, I'm not the only one with this problem with PulseAudio, it doesn't seem like you can set the default audio output device from the UI:
https://wiki.archlinux.org/title/PulseAudio/Examples#Set_the_default_output_sink