19 Sep
2013
19 Sep
'13
12:04 p.m.
On Thu, September 19, 2013 7:42 pm, Fons Adriaensen wrote:
On Thu, Sep 19, 2013 at 06:46:11PM +1000, Patrick
Shirkey wrote:
Can I use jack_delay running on a second computer connected to the
external i/o of the first computer to get this value?
jack_system (in) -> pa_source (in) ->
audacity (in) -> audacity (out) ->
pa sink (out) -> jack_system (out)
Audacity is run in pass through mode with internal latency set to 0.
I would like to measure the round trip latency from jack_system (in) to
jack_system (out)
Easy using jack_delay.
1. Measure the round-trip latency of your sound card (with an
external analog loop).
2. Measure
jack_delay -> pa_source -> audacity -> pa_sink -> jack_delay.
Does this look reasonable?
1023.978 frames 21.333 ms total roundtrip latency
extra loopback latency: 1023 frames
use 511 for the backend arguments -I and -O
1023.976 frames 21.333 ms total roundtrip latency
extra loopback latency: 1023 frames
use 511 for the backend arguments -I and -O
1023.977 frames 21.333 ms total roundtrip latency
extra loopback latency: 1023 frames
use 511 for the backend arguments -I and -O
3. If pa_source and pa_sink are a single Jack client
(probably not),
subtract one period from the result of (2).
Can you explain that with the data above?
4. Add the two values.
I would like to provide an app for this task. Do you think it would be
worthwhile to extend jack_iodelay for this purpose?
--
Patrick Shirkey
Boost Hardware Ltd