[LAD] Jack2 on DROPS/L4 (Diploma thesis) | towards a truly real-time capable FOSS audio distribution

From: micu <micuintus@email-addr-hidden>
Date: Thu Apr 16 2009 - 19:43:45 EEST

Dear Linux Audio Developers,

as indicated by Stéphane in his presentation [1] he gave at LAC2009 today, I
finally handed in my diploma thesis, which I announced here [2]. You can
download the full text of the thesis here:
        
        <http://www1.inf.tu-dresden.de/~s3418892/diplom.pdf> [3].

If you want to take a glimpse at the code, you can get a (still very dirty)
snapshot of the code here [4].

The abstract of the thesis:

> Several available free software audio solutions were analyzed, and
> Jackdmp—a C++ reimplementation of the renowned JACK Audio Connection
> Kit—was selected as the most appropriate solution for a real-time audio
> architecture on DROPS. The JACK sound architecture provides the lowest
> processing latency possible on a desktop computer for a given set of sound
> card parameters. It reduces the latency jitter caused by software to zero
> and synchronizes streams at sample accuracy.

> A real-time admission scheme for JACK clients is proposed.
> The execution time of different typical JACK clients was analyzed with
> measurements to validate the assumptions the proposal is based on,
> but also to gain further knowledge about their timing behavior.
> The measurements showed that the condition set by Paul Davis—the
> time to process a client must be a linear function of the buffer size—holds
> for all tested clients.

> Jackdmp was ported to DROPS. The developed design of the port and its
> implementation is documented here. Measurements showed that—although
> the real-time performance of the Linux kernel is continously being improved
> in the mainline and on special external branches—DROPS can provide a
> signaling latency that is two times lower on average than the values that
> can be achieved on the same machine running with a low latency patched
> Linux kernel. Thus, it can be stated that DROPS is well-suited for
> real-time audio processing and that the pursued path to use it as the
> foundation of a truly real-time capable audio workstation should be
> followed.

As of the project's future: I will try to get the ALSA driver and the
connection with L4Linux working until the presentation of the project (no
date set so far, but probably in 2--4 weeks or so). If all works well, we
will consider releasing a demo disc and / or a Youtube demonstration for
interested developers and power users of the system then. And then we'll
see :).

Kind regards --- and those of you who are in Parma: Have an interesting
conference and a great time in Italy! ---,

micu
===============================================================
[1]<http://linuxaudio.de/lac2009/JACK2_LAC_2009_slides.pdf>
[2]<http://lists.linuxaudio.org/pipermail/linux-audio-dev/2008-July/021384.html>
[3]<http://www1.inf.tu-dresden.de/~s3418892/diplom.pdf>
   // This is only a temporal location, I will inform you about the final
      location here as soon as the document is published there.
[4]<http://www1.inf.tu-dresden.de/~s3418892/code_snapshot_(still%20dirty).tar.gz>

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Received on Thu Apr 16 20:15:01 2009

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