[sdiy] Processing Midi - Dropping Notes

[Theo]

Hi David,

Yes real-time messages can replace expected data just like the example you gave.
Yes the real time message is guaranteed to be one byte only, but more than one real-time message is possible.

Like:
Note on
Note value
Real-time active sensing 
Real-time timing clock
Note velocity

Or:
Note on
Real-time active sensing 
Note value
Real-time timing clock
Note velocity

The real time messages are:
$F8 - Timing clock
$F9 - undefined
$FA - start
$FB - continue
$FC - stop
$FD - undefined
$FE - active sensing
$FF - system reset

The other one byte messages ($F1...$F7) are not real-time and not allowed to go in-between the data of other messages.
However I like to pars them as if they where real-time messages, part for easy of coding.
But also because of timing.
"Midi time code quarter frame" ($F1) is one of them, you don't like that one waiting in a FIFO too long.
And having "Song select"($F3) or "Song position pointer"($F2) waiting in the FIFO while $FA "start" is received and executed in is also a bit sloppy.

Best use a method that takes care of these things automatically.
Like the one I described in the other message.

Cheers,
Theo



  ----- Original Message ----- 
  From: David Brown 
  To: synth-diy at dropmix.xs4all.nl 
  Sent: Friday, July 16, 2004 6:14 PM
  Subject: Re: [sdiy] Processing Midi - Dropping Notes


  At 09:34 PM 7/13/2004, you wrote:

    For even more fun there is also "real time messages" that can come in-between the bytes of other messages.
     
    The real time messages are one byte only.
    So just check if a message is real time, then do something with it, like nothing at all.

  Can you clarify the real time messages?  I'm writing my own MIDI parser and I don't know if I have handled it correctly.  Specifically, can a real time message replace the expected data in a message?  For example ...

  Note on command
  Note value
  Real time message
  Note velocity

  In this case, is the real time message always guaranteed to be one byte?

  Thanks. - Dave 
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