[PlanetCCRMA] Planet CCRMA kernel - capaibilities

Mark Knecht markknecht@attbi.com
Sun Dec 29 11:23:01 2002


Fernando,
   I'm just poking around for info. Thanks in advance. 

   Paul Davis was giving a bit of an explanation on Jackit-Dev about
low-latency operation as a normal user and how this made possible by
using a kernel that has 'capabilities' enabled. He then stated that he
thought your PlanetCCRMA kernel did this, and that your jackstart
application utilizes capabilities to grant low-latency operation to
other Jack apps. I wanted to check that this is true? If I run jackstart
as a user, and then start other jack applications like Ardour as a user,
then do they all get this high level of control over the machine?

   Assuming that it is true, I'm wondering how well the timing of MIDI
Sequencers will survive in this environment? I am struggling through
some really bad MIDI timing issues as I run Rosegarden as a user along
side Ardour and jackstart. I have jack support built into Rosegarden,
but my MIDI timing is terrible. It seems to be a sort of random problem.
I've posted some examples of Pro Tools and Linux playing the same song.
The results are pretty bad.

GOOD - Pro Tools:
http://www.controlnet.com/~makeMusic/Linux/PT_ref_out.mp3

BAD: Ardour/Rosegarden
http://www.controlnet.com/~makeMusic/Linux/RG_Ardour_test.mp3

   Don't get to worried about the actual sound. Please just listen to
the timing. I've not figured out how to make a proper bounce from Ardour
yet and the audio is getting scaled up an clipping.

   Again, the cause of this could be any number of things. I don't have
a clue right now what makes this so bad and am just searching for a
solution.

   Thanks!!

Cheers,
Mark