Re: Major problem with the current alsa mixer.

[Takashi Iwai <tiwai@suse.de>]

At Fri, 12 Sep 2003 13:46:39 +0100,
James Courtier-Dutton wrote:
> 
> Jaroslav Kysela wrote:
> > On Fri, 12 Sep 2003, James Courtier-Dutton wrote:
> > 
> > 
> >>There is a MAJOR problem with the current alsa mixer.
> >>How do I set a mixer volume to the 0 db point. I.E. no attenuation, and
> >>no gain.
> >>Currently, we might have a value from 0 to 100%. Percent of what?
> > 
> > 
> > Percent of the volume range.
> > 
> > 
> >>What this value means varies depending on the sound card hardware being
> >>used.
> >>I think that this should all be changed to signed values, with a max and
> >>a min setting. With a value of 0 being equivalent to no-gain,
> >>no-attenuation. Each alsa-driver would then convert this signed value
> >>into a value actually written to the hardware register via a lookup table.
> > 
> > 
> > Things are not as easy as you like. Using the signed notation for the
> > volume representation does not sound bad, but on the other side, it's
> > great to have zero as minimum value as well.
> 
> Zero as a minimum value is not very meaningfull in audio terms. With a 
> mixer, the zero dB point is probably more use. The minimum value of a 
> slider should be the equivalent of mute, so I think that instead of a 
> minimum value, it should display "mute" for the user.

it's not always true.  some codes provide the minimum value which
doesn't mean mute.  in this case, another lower value would be needed
as the meaming of really minimum "mute".

> The user should be able to reduce the volume, and if they hit the 
> minimum, mute automatically becomes active, but if they increase the 
> volume again, mute automatically is disabled. I am thinking about the 
> way a TV volume/mute control works. If one is muted, turning volume up 
> or down automatically un-mutes the sound. This programming could 
> probably be done at the application level, but I think that as so many 
> people would want it that way, it should maybe move to alsa-lib.

hmm, it's a question whether it should go into alsa-lib.
another upper library seems better for me.

note that i don't mean against this idea at all - i'm absolutely for
this :)
the real problem is, of course, how to implement it for _all_
soundcards and architectures...
 

Takashi


-------------------------------------------------------
This sf.net email is sponsored by:ThinkGeek
Welcome to geek heaven.
http://thinkgeek.com/sf