Re: [Alsa-user] ice1712 recording

[James S. <www...@gm...>]

> You can mix all 4 inputs down into one stream and then record that, but
do you really mean that you can record to 4 separate application threads
concurrently without mixing?

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.

By default sound is often configured for stereo with one track panned
left and one track panned right.  But it's two tracks, not mixed
(until reproduced and analog-illy mixed in air).  Baring cheap sound
devices that have bleed over between tracks with unintentional mixing.
In audacity you can separate the channels and unpan them for two true
mono tracks.  As well as a few CLI options for the same.  Sox is good
for that.

With unix-isms you can send your output to stdout and pipe to stdin of
another app.  Like tee which can then save a file and redirect the
same output to another file.  I've sometimes gone this route to output
the raw WAV and a compressed MP3 at the same time to two different
storage devices / locations.

I seem to recall an arecord option to output each channel as it's own
mono file.  Which you could tail -f on other terminals to pipe that to
other things.  Seems like --separate-channels is that option.

$ arecord --help

- James