On Fri, 3 May 2013, Vincent Gulinao wrote: > 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? Because my impression was that your soundcard had a large number (I chose 18 as an example) of input channels. And that there is no way for the computer to know which of those were paired together. All of my choices were illustrative only to point out to you what to look for. As I said, I have absolutely no idea about your soundcard, how it works, how the driver for it works, etc. Maybe it puts out 16 different pairs and looks to alsa like 16 different sound cards each with a stereo output. In which case you would need a separate line for each. Or maybe it looks like one card with 32 channels. Or whatever. > > 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 OK, change 16 and 32 above for 32 and 64. I have no idea. I have never seen such a card nor do I know anything about it. > all of them will be used at least in the beginning. Is this where the > asoundrc and/or "-D hw:.." comes into picture? Maybe. You say you have installed the card and have a driver for it. What do you get when you do ls /dev/snd? ls /proc/asound? > > / Vincent > > > On Thu, May 2, 2013 at 7:52 PM, Bill Unruh <unruh@xxxxxxxxxxxxxx> 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 | unruh@xxxxxxxxxxxxxx >> Canada V6T 1Z1 | and Gravity | www.theory.physics.ubc.ca/ >> > -- 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 | unruh@xxxxxxxxxxxxxx Canada V6T 1Z1 | and Gravity | www.theory.physics.ubc.ca/ ------------------------------------------------------------------------------ Get 100% visibility into Java/.NET code with AppDynamics Lite It's a free troubleshooting tool designed for production Get down to code-level detail for bottlenecks, with <2% overhead. Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap2 _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
