[pulseaudio-discuss] The volume control ways in PulseAudio

Aaron Chou zhoubb.aaron at gmail.com
Fri Jul 17 09:15:43 UTC 2020

Thanks for your email!

On Fri, Jul 17, 2020 at 4:20 PM Tanu Kaskinen <tanuk at iki.fi> wrote:

> On Fri, 2020-07-17 at 10:57 +0800, Aaron Chou wrote:
> > Hi, all:
> >
> > I am the newer about PulseAudio.
> > When I have some time to learn it, I found that there are two ways in
> > volume control, which is software control and hardware control.
> > I can not understand these two ways.
> > The software way means the volume data will not be sent to the hardware?
> > It is unbelievable.
> Software volume means that PulseAudio modifies the signal to be softer
> or louder. Hardware volume means that PulseAudio sends the signal
> unmodified and tells the hardware to the modification, which requires
> that the hardware provides an interface for controlling the volume (I'm
> currently using a USB sound card that doesn't provide such interface).
I also have an appearance with a USB sound card, and something else is
Such as the volume is set to 0, but it also can play music when the system
reboot or power off.
So I doubt that the volume is not be set to hardware through PulseAudio.

Can I have the following flow chart:

app->pulseaudio(software control)->alsa lib->alsa driver

Do you know how the USB sound driver receives the volume data from
The ioctl? or other else? I can not determine.


> --
> Tanu
> _______________________________________________
> pulseaudio-discuss mailing list
> pulseaudio-discuss at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/pulseaudio-discuss/attachments/20200717/4f5d8dbf/attachment.htm>

More information about the pulseaudio-discuss mailing list