Re: [Jack-Devel] extra latency compensation was Re: is this latency coming from ALSA, jack, or ardour?

On Sun, Apr 17, 2011 at 11:33 PM, Chris Caudle <[hidden]> wrote:
> OK, understanding extra latency compensation better now, but still a bit
> confused by the results.  I can't seem to reconcile the results from
> jack_iodelay with the track to track delays I see in Ardour 3.

i've already mentioned that there are bugs with this in all released
ardour versions.

you will not get a3 doing the right thing UNLESS you disconnect a
"source" track from all other JACK ports when re-recording it to a new
track. i'm not going to explain why this is occuring - its a bug and
it will be fixed, likely in the next several days. ardour will do the
"right" thing if you switch the new track alignment to "capture time".

> So according to jack_iodelay, the additional latency not due to the period
> buffer is 3131 frames (4155 - 1024 frames per period).

this is not correct. my original instructions were more correct. i
will modify jack_iodelay to print a more informative set of output
than it currently does.

> I expected the "extra" latency to be due to the latency in the AD
> conversion and DA conversion, and to be constant for a given sample rate.
> Why such a large difference in extra latency when the period size is
> changed?

its definitely not always constant w.r.t sample rate. it depends on
the nature of the converters used.

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