[PD-ot] Record PCM output - ALSA - Rapsberry Pi

Greg Schroeder gmschroeder at gmail.com
Sun Nov 25 23:54:05 CET 2012


You could write a patch that records 16-bit mono .wav, at as low a
sample rate as you'd like, to .wav with writesf~ . . . more or less
copy-pasting from the help page.
Recording to something besides .wav, especially into a separate
application (which just because it's a separate application will need
more processing power) in realtime, needs encoding (and thus
processing power and RAM) as you write, which is going to be a bigger
problem than disk space on a raspberry pi, I'd think.
How long are you planning to record, and what is your file size limitation?

Someone correct me if I'm wrong, for my information as much as his,
Greg

On Sun, Nov 25, 2012 at 2:48 PM, Pierre Massat <pimassat at gmail.com> wrote:
> Hi Hans,
>
> Thanks for your reply. I can't use writesf~ alone because i want to save
> some disk space, wav is too big.
> Is there a way i can run Pd, and then pipe its output to another program to
> record it whenever I want? I don't want Pd to continuously write to a file
> because i'm running it for hours.
>
> Cheers,
>
> Pierre.
>
>
> 2012/11/25 Hans-Christoph Steiner <hans at at.or.at>
>>
>>
>> [writesf~]
>>
>> .hc
>>
>> On 11/25/2012 05:03 AM, Pierre Massat wrote:
>> > Or is there a way to directly pipe Pd's audio output into another
>> > program?
>> > Too bad JAC doesn't work on the Pi...
>> >
>> >
>> > 2012/11/24 Pierre Massat <pimassat at gmail.com>
>> >
>> >> Hi,
>> >>
>> >> I 've been searching the internet for two days and i couldn't find any
>> >> satisfying answer, so I thought I'd ask here...
>> >> I'm running PD on my Raspberry Pi, and I need to record Pd's output. I
>> >> can't use the standard writesf~ because I lack disk space, and
>> >> oggwrite~
>> >> doesn't work well on the RPi (it records fine but Pd's output is
>> >> trashed).
>> >>
>> >> I recently discovered that i could record something in raw with ALSA
>> >> using
>> >> arecord, and pipe this into oggenc, or flac, or whatever I need to
>> >> record
>> >> the file. Something like:
>> >> arecord <parameters> raw | oggenc <parameter> file.ogg
>> >>
>> >> The thing is that the RPi has no capture device (the single PCM doesn't
>> >> seem to be capable of capture).
>> >>
>> >> A lot of things seem to be possible using a .asoundrc configuration
>> >> file
>> >> for ALSA, but I don't know how to use it.
>> >> What I would want is to copy the PCM output so that ALSA can recognize
>> >> this copy as an input in a record. Note that I need to be able to
>> >> listen to
>> >> the output while recording.
>> >>
>> >> Do you thing this is possible at all?
>> >>
>> >> Cheers,
>> >>
>> >> Pierre.
>> >>
>> >
>> >
>> >
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