Re: [LAU] Testing JACK and PA latency

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To: <linux-audio-user@...>
Date: Thursday, September 19, 2013 - 12:32 pm

Resending as the first one appears to have been blocked.

On Thu, September 19, 2013 8:46 pm, Fons Adriaensen wrote:

external analog loop).
external i/o of the first computer to get this value?

Here's a bit more detail for discussion before I send this over to the PA
guys for feedback.

I am seeing the time period returned by jack_delay regularly increase
during the measurement process. Do you have any thoughts on why that would
be happening? I would like to rule out jack_delay because this is most
likely a bug in PA that I have come across now.

I'm using this method:

jack is now set to 64/48000/2

This is the graph:

jack_delay -> pa_source -> audacity -> pa_sink -> jack_delay

Using audacity with 0 internal latency and in pass through mode I see the
following results. It starts out as 10.667ms and after a few seconds it
climbs up to 70.667 ms.

I see similar results with ecasound instead of audacity using the
following graph and ecachain:

jack_delay -> pa_source -> ecasound -> pa_sink -> jack_delay

ecasound -f:32,2,48000 -b:64 -i alsa -o alsa

In that case it starts at 60.000 ms and climbs upto 572.000 ms after a few
seconds of running the test.

Console logs here:


worthwhile to extend jack_iodelay for this purpose?
it's done, then add or substract.

Patrick Shirkey
Boost Hardware Ltd

Linux-audio-user mailing list

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Messages in current thread:
Re: [LAU] Testing JACK and PA latency, Patrick Shirkey, (Thu Sep 19, 12:32 pm)
Re: [LAU] Testing JACK and PA latency, Fons Adriaensen, (Thu Sep 19, 12:56 pm)