Subject: Re: [linux-audio-dev] midi events in jack callback (was: Reborn)
From: Martijn Sipkema (msipkema_AT_sipkema-digital.com)
Date: Mon Aug 19 2002 - 21:12:47 EEST
> >MIDI through and any other 'immediate' type MIDI messages do
> >not need to be scheduled, they can be written to the interface
immediately.
>
> Yes, they could. It would however necessitate different input routes
> for 'immediate' and 'queued' events to the MIDI output handler.
The MIDI I/O API I am working on has 'scheduled' and 'immediate' queues. I
don't think there is a way around this unless 'immediate' messages are not
used
at all and that is clearly not an option.
> This
> would not help make things simpler. It would also mean that a Sysex
> or pitch/CC burst routed through can delay MIDI clocks because of the
> limited bandwidth on the MIDI wire.
Sysex can hurt timing for other events, but that's MIDI. MIDI clock (any
MIDI realtime message) can interleave other messages. And yes, merging
MIDI streams is not easy.
> Thinking about it -- it's hypothetical because we don't have them in
> Linux yet -- I believe a decent MIDI out handler using a firm timer
> would be an order of magnitude more complicated than one based on the
> RTC. Have you coded one yet?
Yes, and it is not that complex I think. Note that this would only have to
be done
in a driver process or a user-space sequencer application and not for every
client
application.
I'll try to get a version of my MIDI I/O API/framework ready, but it will
probably still
take me some time to get finished.
--martijn
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