On 08/12/16 18:18, James Shatto wrote:
> No, I mean you can record all four channels as input at the same time
> with the same app. Hence the -c 4 aka 4 channels. In audacity you
> just select 4 channels and press record. Once recorded you can break
> them out into 4 mono channels and save each individually (unmixed).
> There's no mixing involved until you configure it to do so. WAV files
> and other audio formats often contain multiple tracks. Individual
> unmixed tracks. They are mixed at the time of playback if configured
> to do so.
Yes that works. I had to select M Audio Delta 44: ICE1712 Multi(hw:0,0)
for recording.
Page 4-30 of the ice1712/envy24 data sheet shows that a multi channel
buffer is used to record "a seamless flow of multiple streams".
So the hardware is capable of multitrack record without using any sound
servers.
Anyway this seems to work with arecord ...
pcm.D44_cslave {
type dsnoop
ipc_key 223456
slave {
pcm "hw:0,0"
rate 48000
period_time 0 # in microseconds
buffer_size 256 # in bytes
period_size 64 # in bytes
channels 4
format S32_LE
}
bindings {
0 0
1 1
2 2
3 3
}
}
pcm.D44_ch12_capture {
type plug
ttable.0.0 1
ttable.1.1 1
slave.pcm D44_cslave
}
pcm.D44_ch34_capture {
type plug
ttable.0.2 1
ttable.1.3 1
slave.pcm D44_cslave
}
Terminal 1 ...
$ arecord -v -DD44_ch12_capture -r 48000 -c 2 -d 60 -fS32_LE ./test12.wav
Terminal 2 ...
$ arecord -v -DD44_ch34_capture -r 48000 -c 2 -d 60 -fS32_LE ./test34.wav
No XRUNs but the buffer settings could do with some further optimisation.
The key is to use a dsnoop instead of a hw as the slave.
Thanks for your help James.
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