RE: Volume per voices [Feature Request]

[Dino <dino@e4a.it>]

Scrive Giuliano Pochini <pochini@shiny.it>:

>
> On 26-Jul-2005 Dino Puller wrote:
> > Hi all,
> >     i don't know if this is the right place to ask for a new feature,
> > BTW here it is:
> > It's should be very useful to have a standard way/function to map volume
> > per PCM stream. For now seems that only emu10k1 and via82xxx has a
> > volume control for each PCM streams, probably because a lack on the
> > others drivers. Where the HW/driver doesn't support this control, it's
> > should be emulated via software.
>
> Most cards have hw volume, but ALSA cannot answer this simple question:
> given this PCM handle, what numid:index control controls the gain of its
> Nth channel ?
This is exactly what i'd like. I'd like to skip this access to a control gain,
and instead create a standard map to the relative pcm stream.

> That question is not as simple as it may seem at first glance. The ctl
> may not exist at all if the cards do not support it or if the PCM is
> not an hardware PCM (eg. is uses dmix). Even if the card has a simple
> 1:1 relation between a PCM device and an hw control, some plugins (route,
> multi or any combination of any plugins) may have shuffled things...
Hmm i know nothing about route and others plugins, but we can use this volume
control only if it's direct and use an emulation otherwise, it's a simple
access to a lookup table and two multipications. This emulation should be done
even if our hardware doesn't support this gain. At this purpouse i'm looking at
the code of cs46xx driver witch play with my soundcard, and i'm trying to add
this controls and its seems to work (a bit buggy but i've just started) btw
it's really simple to do.
Anyway it's strange that alsa doesn't support this feature, because the old GUS
classic supports volume per pcm, volume ramp, and looping! And alsa was born
from it's drivers.

regards,
   Dino

>
>
> --
> Giuliano.
>




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