Am 29.03.23 um 21:20 schrieb BALATON Zoltan:
On Tue, 28 Mar 2023, Volker Rümelin wrote:
it seems your Mac uses a 48kHz sample rate, although QEMU requested a
44.1kHz sample rate. Could you add -audiodev
coreaudio,id=audio0,out.frequency=48000 to your command line and test
if the playback speed and pitch is now correct?
I guess you could also set the sampling rate in the guest to match the
host but if that results it to do resampling then it may use more CPU
that way.
With default settings QEMU resamples the selected guest rate to
out.frequency.
The default for out.frequency is 44100.
I think ALSA and Pulseaudio may also default to 48kHz. I remember
configuring ALSA to 44.1 kHz on my machine to avoid resampling in the
more common case of playing music. So is this a general problem or
something with the coreadio backend? Should this somehow detect the
host sampling rate and do something about it?
Querying the host sample rate and using the host sample rate instead of
out.frequency seems easy. It gets difficult when someone changes the
host sample rate when QEMU is running. Current QEMU code can't change
the sample rate for an established audio stream. I think the Google
Android emulator fork of QEMU uses the Core Audio API to resample the
audio stream in this case.
Regards,
BALATON Zoltan
