ALSA dummy device - how to configure?

Question

I am working on an audio stream between two virtual servers. For that, I have set up a dummy soundcard (as the vservers don't have a hw card) using modprobe snd-dummy. That seems to work fine - I am able to tweak volume levels using alsamixer. Unfortunately, I am not able to record any playback. I used arecord -r 48000 -c 1 to see what's going on, and the output is quite creepy. It contains paths:

Aufnahme: WAVE 'stdin' : Unsigned 8 bit, Rate: 48000 Hz, mono
RIFF$WAVEfmt »data8¶5m8¶5m {D {DXCCC± C²5m  C@P {D°}DxC@C0C! C°~DPÀ}DІCÐ{DÐ{DÀ{DQ`C C  `D(²5m@0re/alsa/bluetooth.confáЂC²5m 0°|Dre/alsa/pulse.confЂC²5mbluetooth.confaC CiceAà|D|D  |Dr/.asoun P°CCX|DÐ{DÀ{DÑ CCÿÿÿÿÿÿÿÿèC`CPC`C C |D¸CCCA CC   CP@Cà~D~DC8¶5m8¶5m {D {DXCCC± C²5m  C@P {D°}DxC@C0C! C°~DPÀ}DІCÐ{DÐ{DÀ{DQ`C C  `D(²5m@0re/alsa/bluetooth.confáЂC²5m 0°|Dre/alsa/pulse.confЂC²5mbluetooth.confaC CiceAà|D|D  |Dr/.asoun P°CCX|DÐ{DÀ{DÑ CCÿÿÿÿÿÿÿÿèC`CPC`C C |D¸CCCA CC   CP@Cà~D~DC8¶5m8¶5m {D {DXCCC± C²5m  C@P {D°}DxC@C0C! C°~DPÀ}DІCÐ{DÐ{

And so on... There mentions of [..]/alsa/pulse.conf, bluetooth.conf and .asoun[drc?] are really really strange.

Does anyone have a clue what is going on here? Have I configured the soundcard the wrong way, or is there anything I missed?

Answer 1

arecord will record from your sound card, which is a dummy, so its not surprising it contains rubbish. You want to record from the network. There are lots of ways to do that, but snd-dummy won't help. You could try pulse-audio - it has good support for network sound, or you could use jack audio - a bit harder to set-up, but less confusing and low latency.