[LAD] JACK and ALSA elucidations

Gianfranco Ceccolini gianfranco at portalmod.com.br
Wed Mar 12 02:26:24 UTC 2014

> On Mon, Mar 10, 2014 at 9:51 AM, Gianfranco Ceccolini <gianfranco at portalmod.com.br> wrote:
> Paul. I’m really sorry for my lack of comprehension, but I still don’t get it.  Is there a relation between the ALSA period with JACK’s 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 patience

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.linuxaudio.org/pipermail/linux-audio-dev/attachments/20140311/e12bbaff/attachment.html>

More information about the Linux-audio-dev mailing list