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:
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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:
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n7dr@shack:~$ arecord -D hw:0,0 -fdat foo.wav
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produces the file foo.wav, with silence.
amixer says:
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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
--
Web: http://www.sff.net/people/N7DR
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