Documentation

[hollunder at gmx.at]

On Fri, 02 May 2008 15:01:30 +0200
"ttoine at ttoine.net" <ttoine at ttoine.net> wrote:

> Philipp,
> 
> It is not so easy. First of all, depending of the sound card chipset,
> some will start with a period at 2, some at 3. As there is no database
> about that point (I can't find one), anyone will have to test. It is a
> good idea imho to create a wiki page with the tested setting of the
> user community, but I don't know if it is easy to motivate people to
> fill that.
> 
> Second point, it is not compulsory to have a real time kernell in
> order to start Jack. If well set up with a long latency (more than
> 60ms), it can starts and works very well too.
> 
> Third point, the frames is the latest point to configure. I mean that
> first, one has to set up the sample frequency he wants to work with
> (44,1, 48, ...), then, try different period values (most of the time 2
> or 3). And then, when RT is activated, it is possible to decrease the
> frame value, so it will decrease the latency time. Basic sound cards
> (like integrated chipsets) will not work well at latency below 20ms.
> And some more professional sound chipset (M-Audio envy24, RME hdsp,
> etc...) will start without matter at a period of 32 or 64, giving
> very low latency around 2 or 3 ms at 48khz.
> 
> Depending the use, the latency has to be different. For example, if
> the aim of the session is only to record a live performance, one can
> work with a latency around 60ms to be sure of the quality of the
> result. If the aim is to work on multi audio tracks with re-recording
> of musicians, the lowest the latency is, the better it is for the
> musicians. And if one wants to use midi, he will have to work around
> 8 ms or 10 ms to avoid midi synchro problems.
> 
> So it means that people will have to test a bit, and configure
> depending their sound card, and their need. And once it is well set
> up, it is possible to save profiles for several uses and sound cards.
> Then, using Patchage is not very difficult to explain.
> 
> A few month ago, I tried to write something on the ubuntu help wiki.
> The problem is how to include on a ubuntu wiki page some screen
> capture ? IMHO, it will be hard to write a good stuff for beginners
> on Qjackctl without any screen capture. If you know how to do that, I
> would be glad to help you.
> 
> Toine

Thanks Luis, the need for this kind of documentation is what drives me,
explaining the same stuff again and again on IRC just can't be it.

ttoine, my plan is to provide set of basic first steps to get jack
running, as this is, from my experience, the most needed thing.
More in-detail descriptions should be on separate pages, else this
JackQuickStartTutorial, or however we will call it, will simply become
too large.

I plan to keep the jack-settings in the tutorial at a high latency, and
I think that most cards work with that, but I will of course tell the
user to experiment and give hints for that, and ask for help on
creating a database of settings. Team members should also contribute to
it, since it's not a lot of effort for them (no extra signup needed).
I appreciate any help on technical details, since there are quite some
things I don't know, for example if rt should be set if the kernel is
generic.
That's all stuff that can be included once the page is there.

On screen capture:
Look at https://help.ubuntu.com/community/HowToQjackCtlConnections,
it appears to be possible. The code seems to be a simple:
attachment:TutQjackCtlConnections2.png
Here's the wikis tutorial page for that stuff:
https://help.ubuntu.com/community/WikiGuide/Screenshots

I'd like to have a nice name for the page for a start, so we can start
to work on it together.
Something similar JackQuickStart would be my choice.
Also, if you think my idea of the thing is flawed, please criticise now.
I may or may not start tomorrow, but it would be best if we already
had that thing up with the release of hardy (I'll base the thing on
hardy).

Best Regards,
	Philipp