Thanks Bill,
The signals I need to record will come from multiple sources (radio
stations) that outputs stereo format, so I guess it means I'd need a "-c 2"
parameter in each of my arecord command then? In what cases is "-c 18" in
your example applicable?
More noob questions: how would arecord determine which channels exactly to
get its signals? This card supports up to 64 input channels, I assume not
all of them will be used at least in the beginning. Is this where the
asoundrc and/or "-D hw:.." comes into picture?
/ Vincent
On Thu, May 2, 2013 at 7:52 PM, Bill Unruh <un...@physics.ubc.ca> wrote:
> On Thu, 2 May 2013, Vincent Gulinao wrote:
>
> Hi everyone,
>>
>> I have a task to setup a system that will continuously capture multiple
>> stereo signals using a MADI audio card (RME HDSPe MADI) and write them
>> into
>> files (perhaps in 1 hour chunks). Few checks I've learned while googling
>> on
>> the topic looks like that my linux setup seem to recognize the card at
>> least.
>>
>
> "Multiple Stereo signals" means what? I have no idea about the MADi
> interface
> or how alsa supports it. But if it does, it may be as simple as arecord
> -Dhw:0 -c 18 -r 48000 -f SB24_LE output.wav
>
> which would keep recording forever into output.wav. You could also use the
> -d 3600 to tell it to record for exactly an hour. You
> would then have to have a script to restart it to a different output file,
> but
> would miss a bit of the stream because of the time to stop and restart. I
> vaguely recall a recording program that will automatically dump into a new
> file every x secods, presumably not missing anything, but cannot remember
> it
> now.
>
> (Note the above tells arecord to use the hardware input, not put it
> through a
> filter like rate changing etc, tells it you want 18 channels, a rate of
> 48000
> samples per sec on each channel, and the input is in 24 bit format with Low
> Order byte order.
>
>
>
>> I'm a total noob in ALSA and audio concepts in general. I've read many
>> docs
>>
>
> If you told us what you were trying to do, someone could probably offer
> better
> advice.
>
> Note that the above assumes that you alsa does support the card without
> problems and the card is card 0 on your system.
>
>
> and forums (e.g. arecord, asoundrc, pulseaudio, jack, etc.) here and
>> there.
>> But while I wait all those info settle in my mind, can somebody pitch here
>> some high-level hints on what things I need to know, or what sort of
>> questions should I be asking, to accomplish this task and make sure I'm on
>> the right direction?
>>
>> Thanks in advance!
>>
>>
> --
> William G. Unruh | Canadian Institute for| Tel: +1(604)822-3273
> Physics&Astronomy | Advanced Research | Fax: +1(604)822-5324
> UBC, Vancouver,BC | Program in Cosmology | un...@physics.ubc.ca
> Canada V6T 1Z1 | and Gravity | www.theory.physics.ubc.ca/
>
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