Re: [LAD] JACK + PA Latency

There is no difference between jack_iodelay and *older* versions of Fons'
original jack_delay, other than the formatting of the output.

He has noted in the past that we should upgrade the code in jack's utility
folder to use his newer version.

On Sun, Sep 29, 2013 at 3:57 AM, Patrick Shirkey <pshirkey@email-addr-hidden
> wrote:

>
> On Sat, September 28, 2013 6:53 am, Fons Adriaensen wrote:
> > On Sat, Sep 28, 2013 at 03:09:36AM +1000, Patrick Shirkey wrote:
> >
> >> The results are quite different so that's a good sign. However they are
> >> still changing on a regular basis so my quest to understand the cause of
> >> this behaviour to find out if it is a localised issue or a bug of some
> >> kind is not over yet.
> >
> > I'd say you have two ways to find out:
> >
> > 1. Get the PA sources and rip them apart,
> > 2. Get the PA authors and make them sing
> > (or rip them apart as well).
> >
>
> The PA Devs are aware of my results and have been very helpful so far. We
> are getting into a murky area where the code has not been worked on
> recently so it takes time to refresh on the specifics.
>
> With the differing results from jack_iodelay and jack_delay that has
> unfortunately thrown a spanner in the works. Now I have to *prove* that
> the new results are completely reliable. That's not an attack on your
> work, just that now I have a new variation that needs to be fully
> explained to make sure there is no doubt, otherwise it's likely that
> fingers will point in other directions.
>
> Some additional empirical data and test results from other people will be
> helpful too.
>
> I have compiled the test procedure into a basic document now:
>
> http://boosthardware.com/pa-jack-latency-test.txt
>
> To recap some of the "results" so far are :
>
> - The combination of JACK + PA is stable on my machine for several days in
> a row even at 64 frames/period and using hda_intel onboard device
> - PA Stream Buffer can give consistent 10ms latency
> - I am now seeing latency between 16ms to 75ms with the new version of
> jack_delay
>
> - There appears to be a bug in the official jack_iodelay which is part of
> the jack utility app suite.
>
>
>
>
> --
> Patrick Shirkey
> Boost Hardware Ltd
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> Linux-audio-dev mailing list
> Linux-audio-dev@email-addr-hidden
> http://lists.linuxaudio.org/listinfo/linux-audio-dev
>

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Received on Mon Sep 30 12:15:01 2013