Virtualbox 4.2 on Quantal doesn't respect VBOX_ALSA_DAC_DEV

[Joseph]

I've long used VBOX_ALSA_ADC_DEV and VBOX_ALSA_DAC_DEV on Virtualbox 4.1 (presently 4.1.26-84997~Ubuntu~precise) to point Virtualbox at a USB microphone. However, Virtualbox 4.2 doesn't seem to pay it any mind.

Note, I am NOT using the USB functionality, instead I'm point VBox to the appropriate soundcard which just happens to be a USB one.

To reproduce, simply install 4.1.23 and point virtualbox to your ALSA ADC/DAC devices. If that works, install 4.2 and see that it doesn't work anymore.

[Frank Mehnert]

The interface has changed. I think setting these environment variables was never documented. The new syntax is

VBoxManage setextradata VM_NAME \
   "VBoxInternal/Devices/ichac97/0/LUN#0/Config/Audio/Alsa/ADCDev" foo
VBoxManage setextradata VM_NAME \
   "VBoxInternal/Devices/ichac97/0/LUN#0/Config/Audio/Alsa/DACDev" bar

This syntax is still not documented and will be subject of further changes but I hope this will work for you in the meantime.

[aeichner]

Please reopen if still relevant with a recent VirtualBox release.

[Yarik]

Hi,

Seems the following syntax does not work any more starting from VirtualBox version 5.0 (as well as for latest 5.1):

VBoxManage setextradata VM_NAME \
   "VBoxInternal/Devices/ichac97/0/LUN#0/Config/Audio/Alsa/ADCDev" foo
VBoxManage setextradata VM_NAME \
   "VBoxInternal/Devices/ichac97/0/LUN#0/Config/Audio/Alsa/DACDev" bar

VM is mapped to default sound card regardless of this options values.

Did this syntax or something else change?

Please advice.

[wiet8phu]

Many thanks for silently closing this issue. ALSA support is still a total disaster in VirtualBox, which is a good product per se. I get no sound using a DMIX configuration, despite there are no errors in the log.

Simply changing the output device (to "dmixer", for example) is not possible, because there's no option in the GUI, no documentation for extradata and the only bug about it is silently closed.

Thanks again.

[wiet8phu]

After looking at DrvHostALSAAudio.cpp , function alsaStreamOpen of the 6.1.4 sources, I can confirm this is at least in 6.1.4 hardcoded to "default".

There is no way to change the ALSA device without recompiling VirtualBox.