Hi!
I have some questions about the minimum and maximum values of a port's latency
(i.e., its latency range). The documentation states the following:
"Both latencies might potentially have more than one value because there may
be multiple pathways to/from a given port and a terminal port."
Does this also apply to a setup with two output ports "A" and "B"
(representing two distinct physical devices) with different capture latency,
which are both connected to the same input port "C"?
Here are some details of an example setup (useful for demonstration purposes,
but probably not for doing any real recording work) as reported by jack_lsp:
"A" (Focusrite Saffire PRO 14 Firewire audio interface):
firewire_pcm:00130e0402403491_1394/Out:01 (Mic/Lin/Inst:01)_in
port latency = 337 frames
port playback latency = [ 0 1792 ] frames
port capture latency = [ 337 337 ] frames
properties: output,physical,terminal,
"B" (Line6 PODxt Live guitar effects processor synchronized by zita-ajbridge):
line6_in:capture_1
port latency = 867 frames
port playback latency = [ 1792 1792 ] frames
port capture latency = [ 867 867 ] frames
properties: output,physical,terminal,
"C" (Ardour track):
ardour:track 1/audio_in 1
port latency = 0 frames
port playback latency = [ 1792 1792 ] frames
port capture latency = [ 867 867 ] frames
properties: input,
Under the assumption that the physical inputs of "A" and "B" represent
the
same time scale, the correct answer for the port capture latency at port "C"
would be [ 337 867 ] and not [ 867 867 ].
So my questions are:
*) What is the rationale behind jack reporting the larger of the two latencies
of "A" and "B" both as the minimum and maximum latency of
"C", and ignoring
the smaller one?
*) Is it possible to provide additional information to jack to state that the
signals at "A" and "B" originate from the same physical source (or
from
different physical sources sharing the same time scale), such that both
latencies of "A" and "B" are taken into account for the latency range
of "C"?
Thanks & kind regards,
Markus