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From: chena1@ese.essex.ac.uk (Chengodan A)
Newsgroups: comp.music
Subject: Need help With MIDI interface S/W Ideas.
Keywords: Keyboard to IBM via MIDI.
Message-ID: <2211@servax0.essex.ac.uk>
Date: 21 Oct 89 12:04:37 GMT
Sender: news@servax0.essex.ac.uk
Reply-To: chena1@ese.UUCP (Chengodan A)
Organization: University of Essex, Colchester, UK
Lines: 76


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A.Chengodan,
ESE,
Essex University,
Colchester,CO4 3SQ,
Essex, UK.

					21/10/89.

Hi,
	I have got more problems to solve with MIDI.
I'm trying to interface an IBM-AT with a keyboard
via MIDI. Now I`m not sure the actual DATA structure 
I need to use on READING THE MIDI MESSAGES; especially
the timing information of each MIDI MESSAGES 

i.e:
In storing the MIDI MESSAGE ( key on/off ..), how do I
include the time field indicating when each note/event 
( key on/off ..) has occurred (relatively/ ??). This is to
make sure the MIDI MESSAGES are sent at a right time on 
playback. 

	How to incorporate this timing in the MIDI 
MESSAGE structure? 

	So far I could only think of these, using:

(1).	hardware:	Reading a Real-Time clock
			with high resolution. 
			
			or

			A special timer set after each
			key is pressed and reset it as
			it's released. ( not sure this is
			that simple when 16 keys are
			pressed simultaneously ....)

(2).	software:	Reading a computers Real-Time 
			clock and calculate the time 
			interval between each event.
			( this might eat-up a lot of 
			CPU's time and miss reading
			the incoming data..).

			The structure which I think suitable
			in C is:

			struc MIDIMSG
			{
				int status;	/* 8 bit integer */
				int data;	/* to make a full */
				int speed;	/* use of memory */
				int time;
			};

(3).	SYSTEM REAL-TIME MESSAGES:
			Using the System Real-Time MIDI Messages
			which provide a TIMING-CLOCK at a rate of
			24 beats per quarter notes.
			If I could use this, what sort of calculations
			or steps I should take to make it work?


	I hope to get some comments and ideas of how I can go around 
solving this problem. I wish you will be able to send some Email for me.

Thank You Very Much.

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Email:	chena1@ese.essex.ac.uk.

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