[pulseaudio-discuss] How do different sound cards dynamically use different configurations?

[zhaochengyi at uniontech.com]

Hi Sean,

Thanks for your reply.

On 2022/7/17 上午3:18, Sean Greenslade wrote:
> On Fri, Jul 15, 2022 at 06:04:49PM +0800, zhaochengyi at uniontech.com 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).

Thanks,
Chengyi