On Sat, May 15, 2010 at 4:23 PM, Philipp Überbacher <hollunder@lavabit.com> wrote:
Qtractor might also be able to do it. Don't know about the others.

Qtractor can do mp3 playback/non-destructive-editing and is fully jack-ified for both MIDI and Audio, per http://qtractor.sourceforge.net/qtractor-index.html
Uses JACK for audio and ALSA sequencer for MIDI as multimedia infrastructures.
Built-in connection patchbay control and persistence (a-la QjackCtl).
Audio file formats support: OGG (via libvorbis), MP3 (via libmad, playback only), WAV, FLAC, AIFF and many, many more (via libsndfile).

A few links on Qtractor showing screenshots of main features:
http://www.straightedgelinux.com/qtractor/howto_qmidi.html
http://www.straightedgelinux.com/qtractor/

If you use Fedora 12, x86_64, you can try the stable release I just built:  http://nielsmayer.com/qtractor-0.4.5svn1517-2.fc12.x86_64.rpm

My opinion of qtractor, posted to PlanetCCRMA http://old.nabble.com/Re:-Qtractor-0.4.5svn1517-p28567324.html
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I strongly second that this version of qtractor be included in the CCRMA repo. It is very solid, and very nice!! I've tested it extensively today and it never crashed, never did anything unexpected, and kept up with everything. I was also wondering when I'll be giving rosegarden another chance, as qtractor is much closer to what I expect as it's based on the last sensible DAW I ever used: Cakewalk Pro Audio ( http://www.rncbc.org/jack/qtractor-0.1.0-whitepaper.pdf ). Yes, rosegarden's integrated notation, extensive feature set, documentation and maturity is great. But the direct integration of audio and midi, and the simplicity and "ease of flow" of qtractor is more important for my purposes. Given that many of the "future features" from the aforementioned whitepaper have already been implemented, I have high hopes that qtractor will be able to remain competitive with any future developments on other platforms and other DAWs.

Other than its complete jack-ification, the thing that makes qtractor stand out is the compatibility with Cakewalk instrument definition files available on the net. For example, I quickly googled-upon http://www.cybertown.com/xginstr.zip --> YamahaXG.ins, a Cakewalk instrument definition file which creates names for patches, voices, banks in my Yamaha db60xg synth-daughterboard. I'm sure all my other synths and gear will be just as easy to find because there's a lot of Cakewalk users on the internet.

Another important feature is midi controller mappings, which are hellishly tedious to implement in a one-off fashion. It is nice that qtractor provides a framework on which people can start sharing control surface layouts and definitions, just like cakewalk did with it's .ins format: http://www.rncbc.org/drupal/node/142
Greatest thanks goes to Mathias Krause aka gizzmo, who contributed with the fundamental code to the new MIDI controller mapping functionality that now widens the Qtractor horizon with regard from generic control surfaces. Being the Behringer BCF2000 a notable example, control feedback is fully supported so that those fancy motorized faders, knobs and lights, actually reflect the whole mixing and editing session state. Some pre-made files are here provided for your convenience: bcx2000.qtc is to import into Qtractor (View/Controllers...) and a couple of presets goes into your BCF2000, Qtractor_Mixer_1-8.syx and Qtractor_Mixer_9-16.syx, respectively for the first and second set of eight channel/track strips.
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-- Niels
http://nielsmayer.com