Re: [PATCH v7] audio/pwaudio.c: Add Pipewire audio backend for QEMU

[Dorinda Bassey <dbassey@redhat.com>]

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>
> Are you sure about sizeof(n_bytes) here? That's 4. ;-)
>
my bad!

>
> Volker's point was that "silence" is the center of the wave range. With
> signed
> range that's zero, yes, but with unsigned range that's 2^(bitdepth) / 2.
>
> So you need to memset() the correct value to generate "silence".
>
I understand now, Thanks. I guess it should work for signed range, so I
would do:

@@ -117,7 +117,9 @@ playback_on_process(void *data)
     }

     if (avail == 0) {
-        memset(p, 0, n_bytes);
+        memset(p, 0, (int32_t) n_bytes);

CMIIW

Thanks,
Dorinda.

On Mon, Mar 13, 2023 at 2:37 PM Christian Schoenebeck <
qemu_oss@crudebyte.com> wrote:

> On Monday, March 13, 2023 2:11:11 PM CET Dorinda Bassey wrote:
> > Hi Volker,
> >
> >
> > > To hear this,
> > > start QEMU with qemu-system-x86_64 -machine pcspk-audiodev=audio0
> > > -device ich9-intel-hda -device hda-duplex,audiodev=audio0 -audiodev
> > > pipewire,id=audio0,out.mixing-engine=off ...
> > >
> > I hear the clipped audio stream with these options. IMO, I don't think
> > memset is responsible for that behaviour, I still hear the harsh sound
> with
> > "-audiodev pa". I also tried using an alternative like:
> >
> > @@ -117,7 +118,7 @@ playback_on_process(void *data)
> >      }
> >
> >      if (avail == 0) {
> > -        memset(p, 0, n_bytes);
> > +        p = g_malloc0(sizeof(n_bytes));
> >      } else {
> >
> > The clipped audio issue is still persistent.
>
> Are you sure about sizeof(n_bytes) here? That's 4. ;-)
>
> Volker's point was that "silence" is the center of the wave range. With
> signed
> range that's zero, yes, but with unsigned range that's 2^(bitdepth) / 2.
>
> So you need to memset() the correct value to generate "silence".
>
> Best regards,
> Christian Schoenebeck
>
>
>

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