At Thu, 30 Mar 2006 16:47:41 -0500,
Lee Revell wrote:
> 
> On Thu, 2006-03-30 at 21:52 +0200, Marcel Witte wrote:
> > I have searched with google and found a lot of /etc/asoundrc...but noone of 
> > them worked correctly.
> 
> Most of the .asoundrc examples people post on the net are garbage.
> Check the list archives for some better examples.
> 
> > My dream is that i can use 5.1-sound with dmix and automatic upmix from 
> > 2channel-sound to 6channel. Is this possible??
> 
> There's still no easy way to do this.  There is some work in progress
> (dmix improvements and new upmixing plugins) to make it easier.
> 
> For now you'll have to choose between dmix and stereo->5.1 upmixing (I
> have never seen a working .asoundrc that does both).

The dmix works fine with 5.1 surround.  The setup of dmix is a bit
complicated and depends on the hardware, but upmixing is easily done
by my new stuff in alsa-plugins package.

Suppose you have ALSA 1.0.11rc4 or better CVS version.
In the case of intel onboard chip (installed as card 0), add the
following to ~/.asoundrc:

        pcm.dmix51 {
                type upmix
                slave.pcm {
                        type dmix
                        ipc_key {
                                @func refer
                                name defaults.pcm.ipc_key
                        }
                        ipc_gid {
                                @func refer
                                name defaults.pcm.ipc_gid
                        }
                        slave {
                                pcm "hw:0,0"
                                period_size 512
                                periods 10
                                channels 6
                                variable_buffer_size true
                        }
                }
        }

The period_size and periods are chosen to suit with 128kb buffer.

Then choose "Channel Mode" to "6ch" on mixer, turn off "Surround Down
Mix" and "Center/LFE Down Mix" (if any).  They could be automatically
set up if you define a hook pcm as found in
/usr/share/alsa/cards/ICH4.conf.  But, here, I don't write it up for
simplicity.

Playing with this PCM will upmix automatically to 5.1.

        % apaly -Dplug:dmix51 foo.wav

For making it to default, define the following in addition:

        pcm.pdmix {
                type plug
                slave.pcm "dmix51"
        }
        pcm.!defalut "pdmix"


In the future version, better pre-configurations for easy use will be
included (hopefully :)


Taksahi


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