[LAD] Trying to understand Jack Midi, (Arpage, Dino)

[fons at kokkinizita.net]

On Mon, Feb 15, 2010 at 12:31:19PM -0500, Paul Davis wrote:

> On Mon, Feb 15, 2010 at 11:35 AM,  <fons at kokkinizita.net> wrote:
> > On Mon, Feb 15, 2010 at 04:18:03PM +0000, james morris wrote:
> >
> >> 1) Is there any way to improve Jack Midi timing when the audio driver has
> >> a high latency?
> >
> > I don't think so. If you set the audio period size to
> > e.g. 4096, jack will call clients only every 85ms, and
> > midi gets delayed as well.
> 
> fons, recall the difference between latency and jitter. the problem
> with the -Xseq backend (and -Xraw too) is that it causes really bad
> jitter in addition to whatever latency is present. a2jmidid (at least
> the current git version) doesn't do this - it keeps the jitter as low
> as possible and the latency is constant.

Yes, you're right. Since midi events get timestamped w.r.t.
the start of the current period a large period just adds
latency and not jitter.

So the solution would be a separate thread that receives
MIDI all the time and not just at the start of a cycle ?

Ciao,

-- 
FA

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E guerra e morte !