Re: [PATCH] audio/pwaudio.c: Add Pipewire audio backend for QEMU

[Christian Schoenebeck]

On Wednesday, February 15, 2023 4:59:47 PM CET Daniel P. Berrangé wrote:
> On Wed, Feb 15, 2023 at 05:18:50PM +0400, Marc-André Lureau wrote:
> > Hi
> > 
> > On Wed, Feb 15, 2023 at 12:51 PM Dorinda Bassey <dbassey@redhat.com> wrote:
> > >
> > > This commit adds a new audiodev backend to allow QEMU to use Pipewire as 
> > > both an audio sink and source. This backend is available on most systems.
> > >
> > 
> > Hmm, I would rather have less audio (and ui) backends in QEMU. (for
> > audio, if I could introduce and keep only one, that would be
> > GStreamer: to remove the others..)
> 
> Even if we take this patch, and don't have a gstreamer impl,
> it feels like we've scope for cutting down the backends.
> 
> The 'oss' driver for example ?  On Linux that's long obsolete,
> with alsa or one of the higher level APIs available.  OSS was
> also use on freebsd, but IIUC,  sndio is better choice there
> now too ?  Deprecate (and later remove) 'oss' now ?

There is indeed little reason to still use OSS nowadays IMO. At least marking
OSS as deprecated would not hurt.

> The 'sdl' driver is setup in meson.build as our lowest priority
> impl, we'll pick any other driver ahead of sdl. Is there any
> compelling reason why we must give users the option of 'sdl'
> for audio when we have soo many other choices available ?
> Even if using SDL for graphics, it seems like we can use any
> other backend for audio. Deprecate (and later remove) 'sdl'
> for audio ?
> 
> IIUC, pipewire is positioned to replace pulseaudio. So if we
> take a pipewire backend, once pipewire is available in enough
> distros we could deprecate the pulseaudio backend and eventually
> remove it. Maybe the same applies for 'jack' ?

AFAIK Pipewire is Linux only, whereas PulseAudio and JACK are available for
Windows and macOS, too. And in it's current version (provided QEMU Pipewire
patch), I don't see it as a full replacement for the JACK driver yet.

> IOW, could we get to
> 
>  - Windows: dsound
>  - MacOS: coreaudio
>  - (Open|Net|Free)BSD: sndio
>  - Linux: alsa/pipewire
> 
> ?
> 
> With regards,
> Daniel
>