Re: [LAD] JACK and ALSA elucidations

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To: Paul Davis <paul@...>
Cc: linux-audio-dev@lists.linuxaudio.org <linux-audio-dev@...>
Date: Wednesday, March 12, 2014 - 2:26 am

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>=20

wrote:
don=92t get it. Is there a relation between the ALSA period with JACK=92s=
period?
How can that be? JACK says -p 128 samples and ALSA says 2 on the PC and =
16 on the BBB
double "buffered" model where the total size of the hardware memory area =
used for transfers (what ALSA calls the "hardware buffer") is always =
twice the "buffer size".
the total hardware buffer size. This is unusual among audio APIs, except =
that JACK follows the same convention in its ALSA backend. You can =
specify the period size (-p) and the number of "periods" that make up =
the hardware buffer.
So if I use -p128 and -n2 it means the kernel will buffer 256 samples =
per interrupt, is it?

Thanks for the patience

Gian=

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On Mon, Mar 10, =
2014 at 9:51 AM, Gianfranco Ceccolini <gianfranco@portalmod.com.br> wrote:

Paul. I=92m really sorry for my lack of comprehension, but I still don=92t=
get it.  Is there a relation between the ALSA period with JACK=92s =
period?they are =
identical.How can that be? JACK =
says -p 128 samples and ALSA says 2 on the PC and 16 on the =
BBB 
note: other audio APIs call this a "buffer". some, like ASIO, force =
a double "buffered" model where the total size of the hardware memory =
area used for transfers (what ALSA calls the "hardware buffer") is =
always twice the "buffer size".
ALSA offers control over *both* the "period" (between interrupts) =
and the total hardware buffer size. This is unusual among audio APIs, =
except that JACK follows the same convention in its ALSA backend. You =
can specify the period size (-p) and the number of "periods" that make =
up the hardware buffer.So if I =
use -p128 and -n2 it means the kernel will buffer 256 samples per =
interrupt, is it?

Thanks for the =
patienceGian=

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Messages in current thread:
[LAD] JACK and ALSA elucidations, Gianfranco Ceccolini, (Fri Feb 28, 5:58 pm)
Re: [LAD] JACK and ALSA elucidations, Jeremy Jongepier, (Fri Feb 28, 8:01 pm)
Re: [LAD] JACK and ALSA elucidations, Gianfranco Ceccolini, (Mon Mar 10, 1:51 pm)
Re: [LAD] JACK and ALSA elucidations, Alex Gagnon, (Mon Mar 10, 2:34 pm)
Re: [LAD] JACK and ALSA elucidations, Paul Davis, (Mon Mar 10, 2:50 pm)
Re: [LAD] JACK and ALSA elucidations, Paul Davis, (Mon Mar 10, 2:26 pm)
Re: [LAD] JACK and ALSA elucidations, Gianfranco Ceccolini, (Wed Mar 12, 2:26 am)
Re: [LAD] JACK and ALSA elucidations, Paul Davis, (Wed Mar 12, 2:50 am)
Re: [LAD] JACK and ALSA elucidations, Gianfranco Ceccolini, (Wed Mar 12, 3:21 am)
Re: [LAD] JACK and ALSA elucidations, Paul Davis, (Wed Mar 12, 12:12 pm)
Re: [LAD] JACK and ALSA elucidations, Jeremy Jongepier, (Wed Mar 12, 11:37 am)
Re: [LAD] JACK and ALSA elucidations, Paul Davis, (Fri Feb 28, 6:12 pm)