On Sun, 19 Mar 2023, Volker Rümelin wrote:
Am 19.03.23 um 18:49 schrieb BALATON Zoltan:
On Sun, 12 Mar 2023, Volker Rümelin wrote:
Am 12.03.23 um 15:09 schrieb Rene Engel:
Tested with -audiodev coreaudio,id=audio0,out.buffer-count=1 to 12
1 is too slow the rest up to 12 has no effect
The sampling frequency of the via-ac97 driver is 48000 Hz under
AmigaOs4.1
Any other ideas?
In audio/audio_template.h in the AUD_open_ functions there is one
ldebug ("open %s, freq %d, nchannels %d, fmt %d\n",
name, as->freq, as->nchannels, as->fmt);
line. Please replace this line with
fprintf(stderr, "open %s, freq %d, nchannels %d, fmt %d\n",
name, as->freq, as->nchannels, as->fmt);
compile and start AmigaOS. Use the default out.buffer-count. I would like
to know the via-ac97 drivers idea of the sampling frequency.
Not sure this helps but I get these with DEBUG enabled in qemu/audio on
Linux host with alsa set to 44100 Hz dmix rate with default settings
without any -audiodev options with AmigaOS guest.
With pegasos2:
audio: open via-ac97.out, freq 44100, nchannels 1, fmt 1##############] 100
%
audio: open via-ac97.out, freq 44100, nchannels 2, fmt 3
alsa: enabling voice
alsa: disabling voice
alsa: alsa_fini
or pegasos2 with ES1370:
audio: open via-ac97.out, freq 44100, nchannels 2, fmt 3
alsa: enabling voice
alsa: disabling voice
alsa: alsa_fini
this does not play as slow as with sam460ex below but maybe a bit slow
which seems to improve with try-poll=off so this may be because of the alsa
backend issue. It's a bit faster with sdl backend, not sure if that's the
right speed or too fast but at least the backend seems to influence
playback speed.
Hi,
I still don't understand how the playback speed can slow down without
changing the pitch.
The pitch also changes when it's playing slow but sometimes the speed
difference is not too big so pitch shift maybe not obvious.
Is it possible that the guest can't provide the audio
frames fast enough and there are buffer underruns in the ALSA backend? But I
think you would hear buffer underruns.
I think we'll need your logging patch to verify this. Or are there some
traces that I can enable to check this?
With sam460ex and ES1370:
audio: open es1370.dac2, freq 44100, nchannels 1, fmt 0
audio: open es1370.adc, freq 44100, nchannels 1, fmt 0
audio: open es1370.dac2, freq 48662, nchannels 1, fmt 0
audio: open es1370.adc, freq 48662, nchannels 1, fmt 0
audio: open es1370.dac2, freq 48662, nchannels 2, fmt 3
alsa: enabling voice
alsa: disabling voice
alsa: alsa_fini
this plays definitely slow and the freq also seems to be off. I may have
different AmigaOS versions on pegasos2 and sam460ex but I they seem to use
the same driver as there were no updates to that part. I'm not sure what
the driver in AmigaOS looks like but it may be similar to the AROS AHI
SB128 one. I don't know if higher level parts in AHI may try to measure
something like you mentioned but at least the card driver does not seem to
do that.
I had a look at the AROS SB128 driver and the AHI Preferences code. There is
no code to measure the audio clock frequency. The frequency selection of
48662Hz seems to be a AROS/AmigaOS bug. This log is from a AROS x86 guest. I
hear some faint static noise but the playback speed is correct.
open pcspk, freq 32000, nchannels 1, fmt 0
open es1370.dac2, freq 44100, nchannels 1, fmt 0
open es1370.adc, freq 44100, nchannels 1, fmt 0
open es1370.dac2, freq 48662, nchannels 1, fmt 0
open es1370.adc, freq 48662, nchannels 1, fmt 0
open es1370.dac2, freq 48662, nchannels 2, fmt 3
open es1370.dac2, freq 44100, nchannels 2, fmt 3
open es1370.adc, freq 44100, nchannels 1, fmt 0
Here you end up with the correct freq but for me it stays at 48662 on
sam460ex so could that explain a speed difference? Also selecting
different sound options in AHI Prefs the test sound sounds quite different
which probably should not if only the resolution or freq is changed but
I'm not sure what the options really set.
There seems to be two independent problems, one is the bug in alsa backend
that you mentioned and something else only affecting sam460ex which causes
the wrong freq to be selected but I have no idea why or what to check
further to find out.
I'm not so sure if your analysis is correct. The ALSA error I mentioned can
significantly increase the processor load, sometimes to the point of stopping
the guest. But it can't directly change the playback speed.
What I meant is we likely have multiple issues (and the slow speed on
sam460ex may even be a guest bug if that's because using 48662 instead of
44100 Hz) but just changing the audiodev and it's options I hear different
results on pegasos2 which does not play that slow as sam460ex so this may
be some alsa backend issue.
I've looked at the alsa and sndio backends to see if I can find what the
issue with poll may be but since I don't know how it works I can't fix it.
What I've noticed is that the sndio backend seems to remove the poll
calbacks while handling the previous poll results and reenable them
afterwards. Would the alsa backend need some flag that is set after
handling poll results so while this is set the poll callback would return
instead of calling the handler again or it really needs to be removed and
reinstalled every time? (Or maybe it's not even the issue you were hinting
at.)
I will write a patch with a few tracepoints for the audio system. With your
help it should be possible to find the cause of the problem. It might take me
a few days to write and test the patch.
Thanks for looking at it, let me know if I can test anything that could
help.
Regards,
BALATON Zoltan
