[Pipewire] Sampling Rate Issues

[TatriX]

Hi!

I'm pretty sure my card is 48000Hz by default.
Here's pw-top output (slightly edited by removing unimportant things, like mics):

S   ID  QUANT   RATE    WAIT    BUSY   W/Q   B/Q  ERR FORMAT           NAME
I  167      0      0   0.0us   0.0us  ???   ???     0    F32LE 2 48000 Firefox
R   87    256  48000  99.7us   1.0us  0.02  0.00  885   S32LE 16 48000 alsa_input.usb-BEHRINGER_X-USB_61C77E02-00.pro-input-0
R  113    900  48000  38.7us   7.0us  0.01  0.00    0    F32LE 2 48000  + Firefox
R   89      0      0  43.4us   8.1us  0.01  0.00    0   S32LE 16 48000  + alsa_output.usb-BEHRINGER_X-USB_61C77E02-00.pro-output-0
R  136   1024  44100    ---     ---   ---   ---   662   S16LE 16 44100  + Audio Stream <<<<< SDL3 app

But when I call SDL_GetAudioDeviceFormat on that device I get the following:

Audio Devices (1)
	2. X-USB Pro (id: 19)
		format: S16LE (0x8010); channels: 16; freq: 44100; frames: 1024

and then if I try to actually play audio the app crashes:

Thread 3 "SDLAudioP19" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7ffff5eef6c0 (LWP 1374847)]
0x00007ffff7c22974 in ?? () from /usr/lib/libSDL3.so.0
(gdb) bt
#0  0x00007ffff7c22974 in ?? () from /usr/lib/libSDL3.so.0
#1  0x00007ffff7c2bac1 in ?? () from /usr/lib/libSDL3.so.0
#2  0x00007ffff7c2d052 in ?? () from /usr/lib/libSDL3.so.0
#3  0x00007ffff7c21a26 in ?? () from /usr/lib/libSDL3.so.0
#4  0x00007ffff718ad4d in ?? () from /usr/lib/libpipewire-0.3.so.0
#5  0x00007ffff5f01634 in ?? () from /usr/lib/spa-0.2/audioconvert/libspa-audioconvert.so
#6  0x00007ffff719c599 in ?? () from /usr/lib/libpipewire-0.3.so.0
#7  0x00007ffff716dfb2 in ?? () from /usr/lib/libpipewire-0.3.so.0
#8  0x00007ffff7fa7246 in ?? () from /usr/lib/spa-0.2/support/libspa-support.so
#9  0x00007ffff7191ce7 in ?? () from /usr/lib/libpipewire-0.3.so.0
#10 0x00007ffff76a32ce in ?? () from /usr/lib/libc.so.6
#11 0x00007ffff772829c in ?? () from /usr/lib/libc.so.6

If I specifically request 48000Hz and 2 channels, it doesn't crash, though the audio is distorted, presumably because there's some sort of rate mismatch somewhere.

I request 2 channels, though I still get 16 back not sure if that's expected.
If I then try to create a stream with the spec returned from SDL_GetAudioDeviceFormat, it complains about wrong channels.
So i set channels back to 2, on the spec and now it's fine.

Maybe somewhat related to #12129.

I realize I have a peculiar setup :) So any debugging advice is welcome.
Thanks!

[TatriX]

I've just tried SDL_AUDIO_FREQUENCY=48000 hint with SDL_AUDIO_DRIVER=pulseaudio.
That fails to bind a stream with "Invalid audio device instance ID"

Then I tried SDL_AUDIO_DRIVER=alsa and that works perfectly - no distortion or anything.

I think pipewire intercepts alsa calls, so the app doesn't block everything else from accessing the sound card.