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Dshare

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I'm no ALSA expert, but since this page was empty and getting information on dshare was not easy I decided to be daring and put something on this page. BTW, most pages about dshare contain .asoundrc snippets in a "this doesn't work" context, so it might be nice to see what did work (for me).

Two things seem to be very important when using dshare :

   pcm_slave.nforce {
       pcm "hw:0"
       channels 6
       rate 44100        # fixed, because all dshare devices must use the same samplerate.
       buffer_size 4096  # make these sizes smaller for lower latency
       period_size 2048
       periods 0
       period_time 0
   }

then use dshare type pcm definitions, bound to the hardware slave :

   pcm.ch12 {
       type dshare
       ipc_key 47110815
       slave nforce
       bindings.0 0
       bindings.1 1
   }

   pcm.ch34 {
       type dshare
       ipc_key 47110815
       slave nforce
       bindings.0 2
       bindings.1 3
   }

   pcm.ch56 {
       type dshare
       ipc_key 47110815
       slave nforce
       bindings.0 4
       bindings.1 5
   }

On top of each dshare pcm device, you could create a plug device to allow other samplerates. See the Plugin Documentation page.


2005-09-18

With the assistance of the above post I finally figured out how to use dshare with the ice1712. With this I can play linuxsampler out of channels 1-4 and fluidsynth out of channels 5-6 simultaneously, with very low latency, and very low cpu load. -Garett Thank you Garret

   pcm_slave.66_slave {
       pcm "hw:1,0"
       channels 8
       rate 44100
       buffer_size 256
       period_size 128
   }

   pcm.66ch1234_dshare {
       type dshare
       ipc_key 18273645
       slave 66_slave
       bindings.0 0
       bindings.1 1
       bindings.2 2
       bindings.3 3
   }

   pcm.66ch1234 {
       type plug
       slave.pcm "66ch1234_dshare"
   }

   pcm.66ch56_dshare {
       type dshare
       ipc_key 18273645
       slave 66_slave
       bindings.0 4
       bindings.1 5
   }

   pcm.66ch56
       type plug
       slave.pcm "66ch56_dshare"
   }

Retrieved from "http://alsa.opensrc.org/Dshare"

Category: ALSA plugins