[LAD] JACK Graph Internal Latency? (was Re: A small article ...)

Ralf Mardorf ralf.mardorf at alice-dsl.net
Thu Apr 29 09:25:29 UTC 2010

Louigi Verona wrote:
> Hey guys!
> I was the one who tested this for Mike. I used Qtractor and Rakarrack.
> In Qtractor I had Audio track 1 and Audio track 2.
> Signal from track 1 was routed into Rakarrack and then into track 2.
> The latency is there and quite audible.
> Louigi.

Maybe it has nothing to do with this:

    -------- Original Message --------
    Subject:     Re: [LAD] JACK Graph Internal Latency? (was Re: A small
    article ...)
    Date:     Thu, 29 Apr 2010 11:17:31 +0200
    From:     Ralf Mardorf <ralf.mardorf at alice-dsl.net>
    To:     michael noble <looplog at gmail.com>
    CC:     linux-audio-dev at lists.linuxaudio.org
    <s2q339c30111004281945ke03e953dp404e0b63e42b563d at mail.gmail.com>
    <m2yeb4b5e1d1004282041j67fd5bcek60636d345c38ba0f at mail.gmail.com>
    <l2y339c30111004282258rfd24b69bo3f86bbd54235ff12 at mail.gmail.com>
    <p2p339c30111004290202u6fec7788ka4b038632ac42c87 at mail.gmail.com>


    I also wonder why JACK's zero-copy implementation could cause issues
    audio apps. There was an issue for Qtractor, anyway, until today I
    believed that there is no latency when using JACK in any way, excluded
    connections regarding to the sound card.
    I never noticed a latency, but maybe it's because I used this insert
    connections for time related FX only, e.g. flanger and delay.

    Interesting to read about latency I never was able to hear.


But anyway, what version of Qtractor do you use? There was an issue 
related to a supposed zero-copy implementation for outdated versions of 
Qtractor, that a long time ago was fixed in SVN or even in the 
previously used CVS.


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