Latency correction with audio/jack 1.9.22

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From: Florian Walpen <dev_at_submerge.ch>
Date: Fri, 10 Feb 2023 12:59:30 UTC

Hi,

a short "heads up" to users of audio/jack:

There is a fix to latency correction on FreeBSD in the latest JACK 1.9.22 
release. This only matters to you if you have measured JACK latency with your 
setup (jack_iodelay) before and apply latency correction in your JACK config.
That would be CLI arguments -I, --input-latency and -O, --output-latency for 
jackd, or the input-latency and output-latency settings for jackdbus.

Any latency measurements with prior versions of JACK will not work for JACK 
1.9.22. You have to measure again and adjust the parameters following an 
upgrade. More info on latency measurement and correction:

https://github.com/0EVSG/freebsd_jack_notes#latency-correction

The change was necessary because the original base latency was one JACK period 
off, leading to invalid measurements in some cases, and the measurements 
depending on the JACK period which shouldn't be.

If you encounter problems with this change, please contact me directly or post 
a bug report on https://bugs.freebsd.org .

FW