[Jack-Devel] I'm confused about latency

[Ralf Mardorf]

On Thu, 2019-04-04 at 18:19 +0200, Alexandre Bique wrote:
> I've tried with qjackctl to set the periods/buffer to 12 with 2048
> samples per buffer at 44100 Hz which is about half a second of
> latency. Do you manage to get the correct latency reported with those
> settings? See https://imgur.com/w45wsp8

Hi,

what's wrong with QjackCtl's calculation?

For the calculation I found a page that seemingly contains a typo.

"(Frames [or buffer] / Sample Rate ) * Periods = Latency in ms" -
https://wiki.linuxaudio.org/wiki/list_of_jack_frame_period_settings_ideal_for_usb_interface

It should read "s" not "ms".

(2048 frames / 44100 Hz sample rate) * 12 periods = 0.557 s IOW 557 ms

Regards,
Ralf