Dear all,
Hello to everyone as this is my first email to the list. I would start with
some background to the problem first.
Background
-------------
(1) My laptop's sound card has stopped playing from the speakers as well as
from the headphones due to internal hardware problems. I think it is a
connection problem from inside as the sound card itself works.
(2) Hence, I have bought a c-media usb sound card with inbuilt FM transmitter
so that I can play my sound from computer to the receiver which can tune to
FM frequencies of my choice.
(3) I successfully setup my .asoundrc to use asym to have dmixed output and
capturing capability from Mic in of my laptop (yes, as I said just laptop
speaker and headphone jack stopped working). I have defined dsp0 also so that
the program using oss could also use the sound card. With that setup my
skype, vmware and everything works as per the expectation.
Problem
---------
(1) Now the problem I am facing is that I would like to record some music
using audacity. As my USB audio doesn't have any capture device or mixer
built in, the only option I get to choose is capture devices provided by my
on-board sound card. But due to my .asoundrc file which uses usb audio as
actual hardware devices, my onboard sound card doesn't get any sound at all
and hence no recording possible in Audacity. So, I came up with following
idea.
(2) I setup a 4 channel virtual device using on-board sound card and usb sound
card using multi plugin. I have used ttables in such a way that the sound is
copied to both the devices. The idea worked great. I could listen to the
music through USB sound card as well as record using audacity. Please look at
the following piece of settings in .asoundrc just for using multi plugin.
============================
pcm.audacity {
type plug
slave.pcm "multi"
ttable.0.0 1.0
ttable.1.1 1.0
ttable.0.2 1.0
ttable.1.3 1.0
}
pcm.multi {
type multi
slaves.a.pcm "hw:1"
slaves.a.channels 2
slaves.b.pcm "hw:0"
slaves.b.channels 2
bindings.0.slave a;
bindings.0.channel 0;
bindings.1.slave a;
bindings.1.channel 1;
bindings.2.slave b;
bindings.2.channel 0;
bindings.3.slave b;
bindings.3.channel 1;
}
pcm.!default {
type plug
slave.pcm "audacity"
}
ctl.audacity {
type hw;
card 0;
}
=======================
The problem with this idea is that I loose the dmixing capabilities on my USB
sound card. I tried to insert dmix plugin in the above chain. So I wrote
following .asoundrc.but I get no sound at all using aplay or any other
application. I have read only one post on this mailing list pointing out the
same problem but didn't have definite answer at the end that it is not
possible. I suspected if multi plugin takes any other virtual device other
than dmix and hence tried to use copy plugin instead of dmix and that also
doesn't work. However,
http://alsa.opensrc.org/How_to_use_softvol_to_control_the_master_volume
describes using virtual devices with multi plugin. Thus, it is not clear why
multi won't work with dmix or my test with copy plugin in the chain.
(a) So could someone confirm that multi plugin to dmix chain is broken or I am
doing something wrong?
(b) In fact, I can alwasy use working multi plugin .asoundrc before starting
to play any music which I want to record but you know it is combursome to
everytime remember to do that
(c) Can someone point out some alternative to be able to use audacity in my
setup described above?
Sorry for the long post.
=========================
pcm.audacity {
type plug
slave.pcm "multi"
ttable.0.0 1.0
ttable.1.1 1.0
ttable.0.2 1.0
ttable.1.3 1.0
}
pcm.multi {
type multi
slaves.a.pcm "dmixer"
slaves.a.channels 2
slaves.b.pcm "hw:0"
slaves.b.channels 2
bindings.0.slave a;
bindings.0.channel 0;
bindings.1.slave a;
bindings.1.channel 1;
bindings.2.slave b;
bindings.2.channel 0;
bindings.3.slave b;
bindings.3.channel 1;
}
# playback channel
pcm.dmixer {
type dmix
ipc_key 1024
slave {
pcm "hw:1,0"
period_time 0
period_size 1024
# preserve true
buffer_size 8192
#periods 128
rate 44100
}
bindings {
0 0
1 1
}
}
pcm.!default {
type plug
slave.pcm "audacity"
}
ctl.audacity {
type hw;
card 0;
}
========================
Regards,
kibanadai
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