Re: [Alsa-user] auto upmix in .asoundrc

[Takashi I. <ti...@su...>]

At Fri, 27 Nov 2009 12:33:36 +0100,
Clemens Ladisch wrote:
> 
> Christopher Schramm wrote:
> > I'm looking for a way to realize an automatic upmix function.
> > 
> > What I got right now in my .asoundrc is a pcm of type route which
> > distributes channels 0 and 1 to a 7.1 signal.
> > 
> > The problem is, when source is a surround signal, every other channel
> > than 0 or 1 gets lost. What I want is stereo signals getting upmixed and
> > everything with more than two channels not getting touched-
> 
> The plug plugin can duplicate channels, like this:
> 
> pcm.mysurround71 {
> 	type plug
> 	slave {
> 		pcm "hw:0,0"
> 		channels 8
> 	}
> 	route_policy duplicate
> }
> 
> However, this will send left/right channels to the center/LFE outputs
> separately instead of mixing them; there is currently no plugin that
> could do this.

The upmix plugin in alsa-plugins is for such a purpose.
See alsa-plugins/doc/upmix.txt.


Takashi