Luppp : Source opened, but still pre-alpha!

Hi All!

With recent changes in the world of live looping software I've decided to open my private repo of Luppp.

The Luppp project has been one of my main occupations over the last couple of years, and I've tought myself C++ programming while working on it. Its a live looping instrument with similar features to the well known software Ableton Live, and more recently Bitwig studio. I feel the live workflow available with such programs is something the Linux Audio community would also benefit from, and hence it will be released under the GPL license, version 3.

Its current state is that most "basic" functionality is in place: Loading, playing back & recording of loops works, effects can be added to these audio streams, and later they are mixed. A basic config file is used to store information about loops, and hence Luppp can make more informed decisions how to use loops.

This is pre-alpha software, as not all features to fullfill alpha state are  implemented. On the other side, most features currently available are quite stable (on my local machine anyway :)

I would like to announce that I will continue to work on the Luppp project myself, but that I do also welcome input / testing / help from other developers. I am aware that there are some basic enough flaws in the program in its current state, however these are also the primary items on my TODO list.

Remember its pre-alpha, please keep that in mind :)
Git source repo: https://github.com/harryhaaren/Luppp
ZIP of master branch: https://github.com/harryhaaren/Luppp/zipball/master

If you're intrested in working on Luppp, have a feature request, have ideas, time, or want to build Luppp a website, feel free to get in contact!!
Cheers, -Harry

Mandatory screenshot (note your GTK theme will influence its looks, this is on the todo! ):

Arch Linux : The quest for a minimal system with maximal RT performance

Hey All,

My install of TangoStudio is getting old, and its repos are getting polluted with conflicts & nastiness, that means a reinstall! So a quick bit of searching for a minimal yet configurable, RT capable and rock-solid led to some intresting distro choices.

TangoStudio - Worked well enough ( 30ms lowest lat on stock kernel )
64Studio - a touch oudated by now, but it was always very good
Pure::Dyne - personal favorite for a while, also gone a touch out of date
Gentoo - probably not good for a non-kernel hacker type... but then

Arch has been a distro I've tried a couple of times because I love the sound of it:

Arch Linux, a lightweight and flexible Linux® distribution that tries to Keep It Simple.

However any time I tried it I had been put off by its "initial configuration" that needs doing before you can get yourself online to look at some forums / wiki's for help!

So off I went, download the 380mb ISO, install it on a seperate partition, get going. You get a minimal system that drops to a root prompt on install, and "startx" isn't going to help much untill you install you video driver packages etc. Note this can be done during install but I opted not to, as I wanted the control to select only needed packages.

So after a bit of haggling with the X server, reading some wiki entries using the text only webbroswer links, and installing the "slim" display manager, messing with /etc/inittab and ~/.xinitrc there's a system up and running, straight to a graphical logic screen (with awesome "darch-white" theme") and then to a barebones LXDE desktop with OpenBox as WM.

The speed of the menu's & actions in unreal, it feels like its there before you clicked. Some small issues with ugly themes and nasty font's were quickly ironed out using lxapperance.

Couple of "nasty" little things:
-Hotkeys: https://wiki.archlinux.org/index.php/Xbindkeys
-Keymap: https://wiki.archlinux.org/index.php/loadkeys
-Touchpad: https://wiki.archlinux.org/index.php/Touchpad

Then on to the audio side of things:
There's a project called ArchAudio, who are maintaining lots of up to date software for audio / multimedia purposes, you'll want to install that repo:
http://archaudio.org/packages/ has all the info you'll need!

I'm a JACK1 user, so first thing I wanted to do was install that:
the "Extra" repository has a build of 0.121.3, so a simple pacman -S extra/jack1 done the trick. FFADO installation for my Echo AudioFire was quick and painless: pacman -S libffado That installs your needed library, the ffado-mixer, ffado-test etc programs, and sets up the privelidges so that you can run JACK in RT mode.

If you want to use this install as your "daily", you'll need to install a mountain of stuff, things like gtkmm,flashplayers, media players, codecs, etc. But if you want to run audio... no need. Actually you'd be better off without that stuff.

The end result:
A system that will run JACK @ 4ms latency, 192kHz samplerate, with a *non-RT* kernel. That's currently still compiling, and I'm hoping to squeeze another ms or 2 off the RT_PREEMPT & IRQ tuning (& IRQ threading.. but that's dangerous territory AFAIK!)

So far I'm very satisfied with Arch and its amazing documentation :)
Will keep this up to date with the RT kernel progress & latency tuning,
-Harry

Tutorial: JACK Ringbuffers

Hey All,

A quick tutorial on basic Jack ringbuffer usage. Ringbuffers are an easy way to exchange data from one thread to another in a realtime safe way. This means that no thread will block when reading or writing, and hence you use ringbuffers in a real-time thread.

For this tutorial I'll be using the "standard" linux audio ringbuffer that comes with JACK. Its docs are available here: http://jackaudio.org/files/docs/html/ringbuffer_8h.html

So what were going to do is:
1. Setup a ring buffer
2. Register a JACK client, and give it a process callback
3. Write data in the "local" thread, ie: our main()
4. Make JACK print out any data it recieves in its RT thread

Note that here the JACK thread is our READ thread , and the main() thread is the WRITE thread. This is important, because a ringbuffer like the JACK one will only work in ONE direction.

Find the well commented source here: https://sites.google.com/site/harryhaaren/Home/main.cpp

Note the compile command is: g++ main.cpp `pkg-config --cflags --libs jack` (its also in the source.. but just to make sure :)

Responses welcome, -Harry

PS: Note there are many different implementations of ringbuffers, all with benefits of their own. The JACK ringbuffer is a simple and IMO easily usable one, and that's the reason I like it. I don't want a fancy impossible multi-read multi-write templated 13 class derived special oval ringbuffer, just something that does what it says on the tin :)