[pulseaudio-discuss] Emulate Alsa A52 plugin in pulseaudio ?

Jim Duda jim at duda.tzo.com
Thu Feb 28 12:09:45 PST 2008

I would like to use pulseaudio on a machine which I have the sound card attached to an digital decoder.  I'm using the 
alsa A52 plugin to perform a stereoupmix from 2 channels to six channels such that I get the same stereo out of the 
front and rear speakers.

Can I use the remap module to copy 2 channels to 4?  The front speaker and sub woofer would be nice too.  The example on 
the pulseaudio twiki for module-remap-sink doesn't quite apply (at least I don't think so).

This is what I have for stereoupmix in ALSA, turning 2 channel stereo into 6 channels via a52 reencoding.  You'll notice 
that I naively attempted to replace the a52 plugin with the pulse plugin after upmix, but that doesn't want to work.

pcm.!default {
    type plug
    slave.pcm "Filter_RateConvert"

pcm.Filter_RateConvert {
    type rate
    slave {
        pcm "stereoupmix"
        rate 48000

pcm.stereoupmix {
    type upmix
    slave.pcm "a52encode"
    channels 6

pcm.a52encode {
#    type pulse
    type a52

pcm.front-spdif {
    type plug
    slave.pcm "iec958"

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