Re: [jessie] recording line-in using ALSA?
D. R. Evans wrote:
> I am trying to set up the ability to record line-in, but have been unable
> to make it work and would appreciate advice. (I have looked at quite a few
> web pages of various kinds of help for ALSA, but all of them seem to be
> rather vague on the details of recording.)
>
> The hardware is very simple:
>
> ----
>
> n7dr@shack:~$ cat /proc/asound/cards
> 0 [IXP ]: ATIIXP - ATI IXP
> ATI IXP rev 2 with ALC658D at 0xfe02a000, irq 17
> n7dr@shack:~$
>
> ----
>
> The card has a mic input, a line input, and a speaker output.
>
> If I simply run aplay with a WAV file, I hear the contents of the file.
> For example:
>
> ----
>
> n7dr@shack:~$ aplay -D hw:0,0 c*.wav
>
> ----
>
> causes the named file to play. So *playing* seems to be fine.
>
> However, I have been unable to find any way to record the line input.
> Everything I have tried has resulted in silence in the output file.
>
> For example:
>
> ----
>
> n7dr@shack:~$ arecord -D hw:0,0 -fdat foo.wav
>
It is very simple
1) find out the input
shell> cat /proc/asound/devices
0: [ 0] : control
1: : sequencer
6: [ 0- 2]: hardware dependent
7: [ 0- 3]: hardware dependent
16: [ 0- 0]: digital audio playback
17: [ 0- 1]: digital audio playback
19: [ 0- 3]: digital audio playback
24: [ 0- 0]: digital audio capture
32: [ 1] : control
33: : timer
56: [ 1- 0]: digital audio capture
64: [ 2] : control
88: [ 2- 0]: digital audio capture
=> my input is the capture on the second card
88: [ 2- 0]: digital audio capture
2) so no we can test the input
shell> arecord -c2 -Dplughw:2,0 -f cd -vv /dev/null
You will see if recording can be done on the screen
> ----
>
> produces the file foo.wav, with silence.
>
> amixer says:
>
> ----
>
> n7dr@shack:~$ amixer
> Simple mixer control 'Master',0
> Capabilities: pvolume pswitch pswitch-joined
> Playback channels: Front Left - Front Right
> Limits: Playback 0 - 65536
> Mono:
> Front Left: Playback 55141 [84%] [on]
> Front Right: Playback 55141 [84%] [on]
> Simple mixer control 'Capture',0
> Capabilities: cvolume cswitch cswitch-joined
> Capture channels: Front Left - Front Right
> Limits: Capture 0 - 65536
> Front Left: Capture 53640 [82%] [off]
> Front Right: Capture 53640 [82%] [off]
> n7dr@shack:~$
>
> ----
>
> which seems to be OK, insofar as I understand it, except that there is no
> indication of whether the capture device is line-in or the mic line. I
> haven't been able to find anything that explicitly tells me how to set the
> capture device to be the line in.
>
> alsamixer looks like this when viewing the Capture item:
>
>
> ───────────────────── AlsaMixer v1.0.28 ─────────────────────┐
> │ Card: PulseAudio F1: Help │
> │ Chip: PulseAudio F2: System information │
> │ View: Capture F6: Select sound card │
> │ Item: Capture Esc: Exit │
> │ │
> │ │
> │ │
> │ │
> │ │
> │ │
> │ │
> │ │
> │ ┌──┐ │
> │ │ │ │
> │ │ │ │
> │ │ │ │
> │ │ │ │
> │ │ │ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ │▒▒│ │
> │ L└──┘R │
> │ CAPTURE │
> │ 82<>82 │
> │ <Capture > │
> │ │
> │ │
> │ │
> │ │
> │ │
> │ │
> │ │
> │ │
> └─────────────────────────────────────────────────────────────┘
>
> I've also tried plugging the incoming audio into the mic socket (in case
> that's what's being captured), and that just records silence as well.
>
> So I suppose that my questions are:
>
> 1. How do I tell alsa that I want to capture from line-in?
>
> 2. How do I actually record the audio that I'm sending on the line-in
> line?
>
> If more information is needed before these questions can be answered,
> please let me know and I'll provide it.
>
> Doc Evans
>
You are looking at PulseAudio, not at ALSA mixer
Try alsamixer -c0 and check the input section
regards
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