[Alsa-user] passing arguments

[Massimiliano C. <mas...@po...>]

hi
my .asoundrc I have:

------------8<----------------------------
pcm.filter {
     @args [ ENNOISE ENBIQUAD FLAT ]
     @args.ENNOISE {
         type integer
         default 0
     }
     @args.ENBIQUAD {
         type integer
         default 0
     }
     @args.FLAT {
         type integer
         default 0
     }
     type test
     slave {
         pcm "play0"
     }
     noise $ENNOISE
     biquad $ENBIQUAD
     flat $FLAT
}
pcm.filter_mono {
     @args [ _ENNOISE _ENBIQUAD _FLAT ]
     @args._ENNOISE {
         type integer
         default 0
     }
     @args._ENBIQUAD {
         type integer
         default 0
     }
     @args._FLAT {
         type integer
         default 0
     }
     type plug
     slave {
         pcm "filter:$_ENNOISE,$_ENBIQUAD,$_FLAT"
         channels 1
         rate 44100
     }
}
------------8<----------------------------

If I use filter device there is no problems, for example:
# mplayer -vo null -ao alsa:device=filter=1,0,0 sweep_100-5000.wav
it plays correctly wav file

but I have to use filter_mono device, and I get an error:
# mplayer -vo null -ao alsa:device=filter_mono=1,0,0 sweep_100-5000.wav
MPlayer UNKNOWN-4.3.3 (C) 2000-2010 MPlayer Team

Playing sweep_100-5000.wav.
Audio only file format detected.
==========================================================================
Forced audio codec: mad
Opening audio decoder: [pcm] Uncompressed PCM audio decoder
AUDIO: 44100 Hz, 1 ch, s16le, 705.6 kbit/100.00% (ratio: 88200->88200)
Selected audio codec: [pcm] afm: pcm (Uncompressed PCM)
==========================================================================
[AO_ALSA] alsa-lib: conf.c:1685:(snd_config_load1) 
_toplevel_:171:33:Unexpected char
[AO_ALSA] alsa-lib: conf.c:3467:(snd_config_hook_load) 
/home/root/.asoundrc may be old or corrupted: consider to remove or fix it
[AO_ALSA] alsa-lib: conf.c:3326:(snd_config_hooks_call) function 
snd_config_hook_load returned error: Invalid argument
[AO_ALSA] alsa-lib: conf.c:3713:(snd_config_update_r) hooks failed, 
removing configuration
[AO_ALSA] Playback open error: Invalid argument


how can I pass arguments from filter_mono to filter device?

thanks