[directmusic] Re: Introduction and question...
- From: ThSteup@xxxxxxx
- To: directmusic@xxxxxxxxxxxxx
- Date: Tue, 5 Nov 2002 00:04:20 EST
In einer eMail vom 04.11.2002 21:18:36 Westeuropäische Normalzeit schreibt
leonewman@xxxxxxxxxxxxx :
<<<
>
> A few more questions...
>
> Do I need to make a tool that will process the MIDI messages that
> SendMidiMsg() sends or is there a default tool that handles the message
> that
> it sends to the performance?
<<<
The MIDI messages are sent directly to the Performance. The performance
reacts like any MIDI-Playback-Device would react to the same MIDI-Messages.
<<<
> Lets say I want to do a pitch-bend up one semitone. If I set it to be plus
> or minus 127 semitones for the range, do I pitch bend it 16384/255? Then
> do
> I convert this to a 14-bit number and split it into the high seven bits and
> low seven bits?
<<<
As far as I remember the relations between the byte-values and the resulting
Pitch-Shift are like that :
MSB_Shift_Amount in semitones = BendRange in semitones/127
LSB_Shift_Amount in semitones = MSB_Shift_Amount/127
Pitch_Bend in semitones = MSB_Shift_Amount*MSB + LSB_Shift_Amount*LSB
So if the Bend Range MIDI-Parameter is Set to + -127 you would have
a BendRange of 254 Semitones
a MSB_Shift_Amount of 2 semitones
a LSB_Shift Amount of approximately 2/127 Semitone which is about 1,6 Cent
thus, given the desired Shift-Amount in Semitones you should get the
following calculation:
MSB = integral_part_of( Desired_Shift_Amount in semitones/2 )
LSB = integral_part_of(2*Desired_Shift_Amount in semitones-4*MSB)/127
<<<
> I have spent most of the learning time with the DirectX SDK documentation.
> It gets a little abstract for me at times. Is there another source that
> would help me with DirectMusic programming? (Any books available?)
<<<
For the DirectMusic Programming the documentaion and the newsgroups are
currently the only sources we use.
For this special task here I found Rob Young's book "The MIDI Files" very
useful for figuering out all the midi message stuff. This book is not exactly
written for software-programmers but it's a good source of information on
MIDI.
Thomas
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