Re: levelmeter?

[Richard G. <rg...@ta...>]

On Thu, 27 Jun 2002, laurent wrote:

> Hi!
>
> I'm thinking about the way to make a levelmeter for Glame ,
> for input/output  of the soundcard . So:
> - Do you think it could be useful ? (one could think it would be better
> in the mixing program , like gmix,
> but there's no mixer with level meter for Linux , as far as I know)

Well - levelmeters are useful of course. But I doubt they'll be useful
within glame, at least they are very difficult to implement in glame.
Instead it should be possible (we talked about this at the LinuxTag with
alsa developers/users) to do a generic levelmeter program using an alsa
plugin (it was the "copy" plugin, if I remember). I.e. the program would
monitor any alsa device without blocking it and just showing a levelmeter.

Such a program would be very useful and could be used in conjunction with
not just glame, but any other program lacking such levelmeters.

> -  Until now, i just looked at the Alsaplayer levelmeter code: it needs
>   a sound buffer to feed the levelmeter.
> In Glame , could the ssp_streamer be ok for feeding a levelmeter ?
>
> - The next thing would be to "connect" the levelmeter somewhere
> ( may be by duplicating when necessary the audio input/output streams)
>
> -  Do we need thread(s) to run the levelmeter ?(  i suppose yes)

You mention the very problems with levelmeters and glame - the audio is
run by plugins, not by the "backend". This makes native glame levelmeters
hard to implement (not impossible, though).

> What do you think of this "project" (or experiment ) ?
> Of course, I will not commit in cvs without your advice !

It would be cool to have someone working on a generic alsa levelmeter
program - you probably want to coordinate/get suggestions from the linux
audio developers mailinglist, too: lin...@mu...
(maybe subscriber posts only).

Richard.

--
Richard Guenther <ric...@un...>
WWW: http://www.tat.physik.uni-tuebingen.de/~rguenth/
The GLAME Project: http://www.glame.de/