15 Jul
2010
15 Jul
'10
10:26 p.m.
On Thu, 2010-07-15 at 21:14 +0100, James Morris wrote:
On 15 July 2010 20:27, Nathanael Anderson
<wirelessdreamer(a)gmail.com> wrote:
Perhaps the source code for Qtractor could help.
I've got timing issues, but they have nothing to do with JACK transport.
I guess (didn't use it) JACK transport is okay, with the limits Rui
mentioned today. Usually Rui does good programming.
-------- Forwarded Message --------
From: Rui Nuno Capela <rncbc(a)rncbc.org>
To: Ralf Mardorf <ralf.mardorf(a)alice-dsl.net>
Cc: Robin Gareus <robin(a)gareus.org>rg>, Devin Anderson
<devin(a)charityfinders.com>om>, qtractor-devel
<qtractor-devel(a)lists.sourceforge.net>et>, 64studio-devel
<64studio-devel(a)lists.64studio.com>om>, Linux-Audio-Dev
<linux-audio-dev(a)lists.linuxaudio.org>
Subject: Re: [LAD] Transport issue for Qtractor - has impact to the
jitter issue
Date: Thu, 15 Jul 2010 09:33:53 +0100
On Thu, 15 Jul 2010 10:15:53 +0200, Ralf Mardorf wrote:
If I don't find anything I want to hack
something together, so a primer on
midi tempo sync, and how to program with it would be appreciated.
Hi Nathanael,
I'm using JACK MIDI which makes it quite easy (compared with designing
the program architecture) to output MIDI events.
I'm also trying to use JACK transport to a) sync with other timebase
master programs, b) to act as a simple timebase master.
The JACK timebase and transport documentation focuses on using JACK to
accomplish these tasks.
see here: http://jackaudio.org/files/docs/html/transport-design.html
There is also a transport example in the examples directory within the
source code for JACK.
But these documents do not go into the issues you'll come across when
trying to accurately synchronize your application with another. Or
accurately acting as timebase master (ie you've recorded some audio
sequenced by your MIDI program acting as timebase master but it does
not line up when imported into a DAW with the same tempo/meter).
Beyond this, you'll have to look into other software source code
(AFAIK). But it's far from trivial.
Cheers,
James. Transport issue for Qtractor - has impact to the
jitter issue
what transport issue? oh i see... :)
qtractor has in fact a known trouble with jack transport sync when slaving
to period/buffer sizes greater than 2048 frames. it skids. maybe that's
exactly what you're experiencing when running jackd -p4096.
i'll recommend for you to turn jack transport mode to "none" or
"master"
only, never "slave" nor "full" on those situations (in
view/options.../audio/jack Transport).
another recommendation would be to grab the latest from svn trunk where
the said trouble has been already mitigated :)
cheers