Need Audio recorder for capturing from output of soundcard

JosephS · 02-16-2017, 10:54 PM

Using Debian Jesie

I need something to record from my soundcard. I have tried audacity but not able to get it working. I need something that works. What are some good recording software that works in linux? I do google searches with not much luck. Mostly get hits for Audacity.I cna't get audio control set up properly for Audacity. It would be good to have more than one audio recorder anyway.

Thanks,

Joe

bat999 · 02-17-2017, 03:34 AM

teckk · 02-17-2017, 10:46 AM

If you have snd-aloop kernel module

Code:

find /lib/modules/`uname -r` | grep snd

Make a virtual loopback device, then you can record whatever comes through the sound device, regardless of having a sound device that doesn't allow it.

Example:
~/.asoundrc

Code:

pcm.!default {
  type asym
  playback.pcm "LoopAndReal"
  #capture.pcm "looprec"
  capture.pcm "hw:0,0"
}

pcm.looprec {
    type hw
    card "Loopback"
    device 1
    subdevice 0
}


pcm.LoopAndReal {
  type plug
  slave.pcm mdev
  route_policy "duplicate"
}


pcm.mdev {
  type multi
  slaves.a.pcm pcm.MixReale
  slaves.a.channels 2
  slaves.b.pcm pcm.MixLoopback
  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.MixReale {
  type dmix
  ipc_key 1024
  slave {
    pcm "hw:0,0"
    rate 48000
    #rate 44100
    periods 128
    period_time 0
    period_size 1024 # must be power of 2
    buffer_size 8192
  }
}

pcm.MixLoopback {
  type dmix
  ipc_key 1025
  slave {
    pcm "hw:Loopback,0,0"
    rate 48000
    #rate 44100
    periods 128
    period_time 0
    period_size 1024 # must be power of 2
    buffer_size 8192
  }
}

Load the kernel module

Code:

modprobe snd-aloop

Capture Audio to m4a:

Code:

ffmpeg -f alsa -i hw:1,1 -c:a aac -b:a 32k -vn OutFile.m4a

When you are done if you want:

Code:

mv ~/.asoundrc ~/.loop_asoundrc && modprobe -r snd-aloop

You'll need to use your own device parameters.

jefro · 02-17-2017, 02:49 PM

I'd find out why Audacity® didn't work. (funny, they copy protected the name)

Using pulse, jack or alsa may be part of the issue??

lspci | grep -i AUDIO

dmesg | grep -i sound

JosephS · 02-17-2017, 09:39 PM

Quote:

Originally Posted by teckk

If you have snd-aloop kernel module

Code:

find /lib/modules/`uname -r` | grep snd

Make a virtual loopback device, then you can record whatever comes through the sound device, regardless of having a sound device that doesn't allow it.

Example:
~/.asoundrc

Code:

pcm.!default {
  type asym
  playback.pcm "LoopAndReal"
  #capture.pcm "looprec"
  capture.pcm "hw:0,0"
}

pcm.looprec {
    type hw
    card "Loopback"
    device 1
    subdevice 0
}


pcm.LoopAndReal {
  type plug
  slave.pcm mdev
  route_policy "duplicate"
}


pcm.mdev {
  type multi
  slaves.a.pcm pcm.MixReale
  slaves.a.channels 2
  slaves.b.pcm pcm.MixLoopback
  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.MixReale {
  type dmix
  ipc_key 1024
  slave {
    pcm "hw:0,0"
    rate 48000
    #rate 44100
    periods 128
    period_time 0
    period_size 1024 # must be power of 2
    buffer_size 8192
  }
}

pcm.MixLoopback {
  type dmix
  ipc_key 1025
  slave {
    pcm "hw:Loopback,0,0"
    rate 48000
    #rate 44100
    periods 128
    period_time 0
    period_size 1024 # must be power of 2
    buffer_size 8192
  }
}

This is what I sound for my snd-aloop:
/lib/modules/3.16.0-4-amd64/kernel/sound/drivers/snd-aloop.ko
Can I just use your script?

Quote:

Capture Audio to m4a:

Code:

ffmpeg -f alsa -i hw:1,1 -c:a aac -b:a 32k -vn OutFile.m4a

Does pulse mess up the use of alsa?

JosephS · 02-17-2017, 10:47 PM

Quote:

Originally Posted by jefro

I'd find out why Audacity® didn't work. (funny, they copy protected the name)

Using pulse, jack or alsa may be part of the issue??

lspci | grep -i AUDIO

joe@BunsenLabs:~$ lspci | grep -i AUDIO
00:05.0 Audio device: NVIDIA Corporation MCP61 High Definition Audio (rev a2)

dmesg | grep -i sound

joe@BunsenLabs:~$ dmesg | grep -i sound
[ 11.456032] sound hdaudioC0D0: autoconfig: line_outs=4 (0x14/0x15/0x16/0x17/0x0) type:line
[ 11.456039] sound hdaudioC0D0: speaker_outs=0 (0x0/0x0/0x0/0x0/0x0)
[ 11.456042] sound hdaudioC0D0: hp_outs=1 (0x1b/0x0/0x0/0x0/0x0)
[ 11.456045] sound hdaudioC0D0: mono: mono_out=0x0
[ 11.456047] sound hdaudioC0D0: inputs:
[ 11.456051] sound hdaudioC0D0: Front Mic=0x19
[ 11.456054] sound hdaudioC0D0: Rear Mic=0x18
[ 11.456057] sound hdaudioC0D0: Line=0x1a
[ 13.276961] input: HDA NVidia Front Mic as /devices/pci0000:00/0000:00:05.0/sound/card0/input8
[ 13.277134] input: HDA NVidia Rear Mic as /devices/pci0000:00/0000:00:05.0/sound/card0/input9
[ 13.277301] input: HDA NVidia Line as /devices/pci0000:00/0000:00:05.0/sound/card0/input10
[ 13.277458] input: HDA NVidia Line Out Front as /devices/pci0000:00/0000:00:05.0/sound/card0/input11
[ 13.277616] input: HDA NVidia Line Out Surround as /devices/pci0000:00/0000:00:05.0/sound/card0/input12
[ 13.277788] input: HDA NVidia Line Out CLFE as /devices/pci0000:00/0000:00:05.0/sound/card0/input13
[ 13.288538] input: HDA NVidia Line Out Side as /devices/pci0000:00/0000:00:05.0/sound/card0/input14
[ 13.288757] input: HDA NVidia Front Headphone as /devices/pci0000:00/0000:00:05.0/sound/card0/input15

I don't know what to do with this.

I got Audacity to work today. I don't know why that is. I don't see what I did different. I chose monitor built-in audio analogue stereo. Yesterday Audacity kept freezing on me and I had to terminate it with kill.

I also tried vlc today to record. Using view > advanced controls, > chose audio capture > built-in audio capture
However when I played the file the sound was only a whisper. Xould hardly hear it.

If I tried moniter built-in audio capture I get a bad sound while listening.

I don't really understand pulse.

jefro · 02-18-2017, 03:12 PM

When I think of the times I had problems with volume levels there were two issues. One was some setting like -20db that was checked. The other was I was using mic as input and not internal line passthrough to capture sound.

Shadow_7 · 02-20-2017, 09:48 AM

Pulse doesn't understand pulse.

I tend to use a pulseaudio over jackd configuration. When you need to do something fancy / odd you can use qjackctl to change the routes to get what you need. Otherwise you need the loop stuff and direct access.

$ find /lib/modules/$(uname -r)/ -iname '*snd*loop*'

Audacity can be pretty non-functional without a .asoundrc to tell it which end is up. Or other less than obvious configurations for other audio applications. Like hostname and /etc/hosts to be setup and configured, so the client and server model functions even though nothing else about it uses networking. Kids these days.

Doug G · 02-20-2017, 01:56 PM

Audacity works fine for me in Fedora 25 w/ pulse. It was a little tricky to set up, first visit was to the pulse audio volume control to choose Monitor as an input source (monitor devices weren't enabled by default for me) Then I had to fiddle with the Device toolbar in Audacity to set the audio host, recording device and playback device properly.

After those one-time setup steps I've been able to record anything that was playing sound without any problems.