[pulseaudio-discuss] [PATCH 5/5] man: sync_volume parameters to manual page

Colin Guthrie gmane at colin.guthr.ie
Sat Oct 16 04:21:51 PDT 2010

'Twas brillig, and David Fries at 16/10/10 04:48 did gyre and gimble:
> This is what I came up with, take it or leave it.

I've tweaked the wording again. Hopefully it's OK, but further patches
can be made if needed.

>>    </option>
>>    <option>
>>      <p><opt>sync-volume-extra-delay-usec=</opt> The unit of time all HW
>>      volume changes are delayed. Negative values are also allowed.
>>      Defaults to 0.</p>
>>    </option>
> How about "sync-volume-hw-delay-usec=" ?  Then,
> The unit of time all HW volume changes are delayed if the volume
> changes are a constant time early. Negative values are also allowed.

I don't want to change the name of the option as that will affect the
other patches. Also I think if this proves to be needed then it
something we'd apply on a per-hw basis which means that ultimately we'd
need to build up a database of hw and the values. This information will
likely come from either alsa or from udev and not be a setting you apply
in the daemon.conf (which applies to all hardware you have on your machine).

So I'll leave this as it is for now.

> On Fri, Oct 15, 2010 at 10:22:16AM +0200, Paul Menzel wrote:
>> I am still thinking that a ???normal??? users does not have a clue on how to
>> determine to what value these options should be set. So it should be
>> marked as expert value or something or a hint should be given on how one
>> can determine what values should be used.

I think any values entered would be mostly trial and error anyway.

> A program could measure the hardware mixer latency by playing a square
> wave on one stream and adjusting the volume of another stream playing
> silence.  Then adjust the parameters so that the wave doesn't vary as
> the volume changes.  Too bad sound cards don't have the internal
> analog loopback control anymore, now you would need to externally loop
> the audio back.

I think "normal" users wont know how to use "man ..." :p

Yes this could be useful. If anyone writes such a tool, then we can
certainly reference it here.



Colin Guthrie

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