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Whooie

Member

Registered: 2015-12-16

Posts: 6

[SOLVED] Using the snd-aloop module to capture internal audio

Hello, I'm trying to set up a way to record the audio being put out by an application (dolphin emulator, in this case). I've come across the snd_aloop module, and loaded it with

# modprobe snd-aloop

which gives me a virtual sound card with two devices, each with eight subdevices. Here's the output of aplay -l

$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM]
  Subdevices: 8/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
card 0: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM]
  Subdevices: 8/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
card 1: PCH [HDA Intel PCH], device 0: ALC269VC Analog [ALC269VC Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 2: Headset [Logitech G430 Gaming Headset], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

and arecord -l

$ arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: Loopback [Loopback], device 0: Loopback PCM [Loopback PCM]
  Subdevices: 8/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
card 0: Loopback [Loopback], device 1: Loopback PCM [Loopback PCM]
  Subdevices: 7/8
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1
  Subdevice #2: subdevice #2
  Subdevice #3: subdevice #3
  Subdevice #4: subdevice #4
  Subdevice #5: subdevice #5
  Subdevice #6: subdevice #6
  Subdevice #7: subdevice #7
card 1: PCH [HDA Intel PCH], device 0: ALC269VC Analog [ALC269VC Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 2: Headset [Logitech G430 Gaming Headset], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

I've set an .asoundrc

$ cat ~/.asoundrc
defaults.pcm.card 0
defaults.pcm.device 0
defaults.ctl.card 0

Now what I think should be happening is when I have an application (I made sure to re-open it too) play audio, it should be sending it to device 0 on the virtual sound card, but when I try to capture audio from either of the devices on that card with

$ ffmpeg -f alsa -i hw:0,0 test.wav
$ arecord -D hw:0,0 -f S16_LE test.wav

or even just in Audacity (I've also tried hw:0,1), I don't get any sound. It records the file and saves it, but when I play it with mplayer (after changing my .asoundrc back to something that will play sound through real speakers), there's no sound. I'm not really sure what I'm doing wrong here.

EDIT: Well, I had to reboot for an unrelated problem, and whoop-dee-doo wouldja look at that, it works now. Now I feel like an idiot.

Last edited by Whooie (2016-01-19 07:22:45)

spnzdg

Member

Registered: 2019-07-22

Posts: 2

Re: [SOLVED] Using the snd-aloop module to capture internal audio

This is an old post. But you saved my day.

I did

modprobe snd_aloop

  as root, and no sound anymore.

Made .asoundrc file, rebooted and

thanks.

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Kernel: 5.2.1-arch1-1-ARCH x86_64 bits: 64 Quad Core model: i5-2500 bits: 64 type: Cache: 6144 KiB :: 1600/3700 MHz Core speeds (MHz) :: Intel 2nd Gen Graphics driver: i915

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,132

Re: [SOLVED] Using the snd-aloop module to capture internal audio

Closing thi old post.