Hi Sean,
On 2022/7/20 上午2:59, Sean Greenslade wrote:
On Mon, Jul 18, 2022 at 02:42:07PM +0800, zhaochengyi@xxxxxxxxxxxxx wrote:
On 2022/7/17 上午3:18, Sean Greenslade wrote:
On Fri, Jul 15, 2022 at 06:04:49PM +0800, zhaochengyi@xxxxxxxxxxxxx wrote:
Hi guys,
On a special PC, it is required to start the pulseaudio daemon
with some special parameters in the file /etc/pulse/daemon.conf,
as follows:
-------
default-sample-rate = 48000
default-fragments = 2
default-fragment-size-msec = 20
-------
When plugging in a USB headset with a separate sound card to this special
PC,
I found that there was a noise in the playback audio. After investigation,
the sound card of the USB headset needs to use the following default
parameters.
-------
default-sample-rate = 44100
default-fragments = 4
default-fragment-size-msec = 25
-------
After my further investigation, I found that noise is only generated
when changing the sink-input volume (pa_context_set_sink_input_volume),
but not when changing the sink volume (pa_context_set_sink_volume_by_index).
Can you describe this noise more specifically? Does it go away with
larger fragment size / counts? Have you enabled or disabled tsched? Have
you run with Pulse debug logging enabled and looked for any hints there
(e.g. underruns)?
I found out I only modified the item default-sample-rate in the file
'/etc/pulse/daemon.conf', and then it will occur the the noise when
changed the sink input volume.
default-sample-rate = 48000
; alternate-sample-rate = 48000
I think the merge_requests 120 can fix this noise issue:
https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests/120
Thanks a lot.
Best Regards,
Chengyi
