Am 19.09.2013 10:46, schrieb Patrick Shirkey:
Moving this thread to LAU as it seems to be a more
generic issue now:
I am testing the round trip latency when using PA and JACK together. I
have the following connection graph:
jack_system (in) -> pa_source (in) -> audacity (in) -> audacity (out) ->
pa sink (out) -> jack_system (out)
Unless your research is completely academic I do not see a practical use
for its results on the user-side. For Audacity latency is not a big
issue. It does not build for realtime-application rather for offline
editing, audio-restauration etc, in that field a latency of 100ms is
still OK....
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)
This is a slightly unusual request but it is actually a reasonably
important measurement in the bigger scheme of things.
Does anyone have any suggestions?
Ideally I would like to get accurate measurements for both input and
output latency.
input:
jack_system (in) -> pa_source (in) -> audacity (in)
output:
audacity (out) -> pa sink (out) -> jack_system (out)
So a tool that allowed me to measure the latency between every node on the
graph would be perfect.
Obviously made alot harder by mixing PA and JACK together. I have tried
jack_iodelay but it does not measure the input signal from the mic instead
it provides it's own signal.
I suppose I could modify jack_iodelay to accept an input signal as the
starting point for the latency graph but I have not looked into the code
yet to see how tricky that would be.
--
Patrick Shirkey
Boost Hardware Ltd
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