Re: [Jack-Devel] MIDI support for OpenBSD?

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DateThu, 14 Jun 2012 07:24:12 +0200
From Hans Petter Selasky <[hidden] at c2i dot net>
To[hidden] at lists dot jackaudio dot org
Follow-UpClemens Ladisch Re: [Jack-Devel] MIDI support for OpenBSD?
On Wednesday 13 June 2012 22:45:16 Ralf Mardorf wrote:
> On Wed, 2012-06-13 at 22:00 +0200, Hans Petter Selasky wrote:
> > On Wednesday 13 June 2012 12:13:19 aCOSwt wrote:
> > > Hello,
> > > 
> > > Congratulations for your project.
> > > 
> > > *BSD are great OSes indeed.
> > > But... might not be the best choice as far as MIDI is concerned.
> > > I personally switched my desktop from freeBSD 6 to Linux because of
> > > MIDI. My opinion is that playing with MIDI, you will quickly realize
> > > the need for a good synchronization between events.
> > > I am not sure *BSD's schedulers can be tuned for reaching the levels of
> > > latency / interactivity this synchronization requires.
> > > 
> > > Sorry for this not positive and a bit out of topic piece of advice.
> > 
> > Hi,
> > 
> > I've been using FreeBSD exclusivly for USB MIDI since v8.0, and the ping
> > time on MIDI using a graphical userland application is less than 6
> > milliseconds for one command looped back. What timings are you seeing?
> > 
> > Please also note there is now a dedicated USB MIDI driver in FreeBSD 8+
> > which talks RAW MIDI.
> 
> 6ms fix latency are more than just ok, but jitter anyway could be
> audible. If the 6ms aren't fixed, but should fluctuate between 0 and 6
> ms, this could break timing, grooves. What humans are able to hear and
> to play IMO isn't equatable to what we feel, when we're grooving and
> btw. I don't trust measurements. I don't know the abilities of BSD, but
> all PCs running Linux, Win, Mac, tend to have issues with MIDI, so if
> BSD has a lack regarding to MIDI, you should reconsider to switch to
> Linux. MIDI on PCs always could cause issues, so an OS that tries to
> support MIDI as good as possible is my choice, IOW, Linux, Win, Mac are
> worse a try, any OS that is known for extra weak MIDI support might be a
> guarantor for possible issues, OTOH a pioneer always is needed to go the
> first steps.
> 

Hi,

If sending out MIDI data real fast and accurately is important, you should 
never use Windows I know. It's MIDI system seems not capable of sending more 
than one MIDI command per millisecond at FULL speed USB, because they don't 
take full advantage of the USB MIDI specification. Some hardware manufacturers 
then won't decode more than one MIDI command per ms either, because they think 
this feature in USB MIDI is not used at all, and that's why we have the 
"UQ_SINGLE_CMD_MIDI" quirk in FreeBSD.

--HPS
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