Re: Volume Peak display

[Takashi Iwai <tiwai@suse.de>]

At Wed, 24 Sep 2003 10:33:43 -0400,
Manuel Jander wrote:
> 
> Hi Takashi,
> 
> I was thinking that wouldn't it be a good idea to have a "visualization"
> category for alsa controls ? Or at least some naming scheme that allows
> to identify controls that should just show some data, like VU meters, or
> the hardware EQ peak i'm implementing for the aureal vortex.

well, the volatile flag should be used for such a purpose.
if it's set, the control change won't be notified to the application.
the application which shows these controls must re-read the data
periodically (not passively like others).

the other flag name might be more obvious, though.

> 
> > > 
> > > - The peaks doesnt get updated by alsamixer nor alsamixergui.
> > > I set the "volatile" flag, but is doesnt have any effect.
> > 
> > this is inteintional.
> > (otherwise it will be too heavy for terminals over a slow network
> >  connection :)
> > 
> > for these purposes, we'll need anyway a special mixer app like
> > envy24control.
> 
> Ok. I got it. I'll start writing our "Vortex turbo  mixer" as soon as i
> can :-)
> 
> > > - Alsamixer shows only 4 of the peak control set (20 total), and other
> > > mixers just show 2 of them.
> > 
> > maybe the result of abstraction by simple-mixer API.
> > 
> > > - The controls are declared as read only, but i can change their value.
> > > This shouldn't be allowed.
> > 
> > really?  then it must be fixed.
> > could you elaborate how this can happen?
> 
> This could be a problem of the mixer app. I mean that i can modify the
> sliders on alsamixer or alsamixergui. The alsalib doesnt try to invoke a
> "control_put()" function (which is correct), since that would yield a
> segfault (i didnt implemented the control_put(), because that would be
> nonsense). 
>
> What i wanted to say, is that it shouldn't be possible in a mixer app to
> "Move" sliders from readonly controls. Their appearance should be
> different too. They should look like "progress bars" or something else.
> Or better than that, VU meters should look like VU meters :)

agreed.  at least, showing the elements with volatile in alsamixer
doens't make sense unless alsamixer shows vu meter (hey, it's not bad
:)


Takashi


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