With some opcodes such as diskin & the granular opcodes, the pitch is determined by a ratio ex. 1 = no change, 2 = octave up, .5 = octave down.

If one knows the pitch of the input file, for example A2, what is the recommended way of dealing with this? So if I want to be able to use cpspch, mtof or cpsmidinn etc. to determine my note choices and apply those to the pitch parameter of the opcodes that use ratios, what would be a good method to approach it?

I'm not particularly good at math... so far the idea I had was something like this (assuming input sample is A2, 110 Hz), which is just dividing standard freq by the sample freq:

  instr 1
kfreq  = cpspch(8.09)
knote  = kfreq/110
printk .1, knote
kfreq2 = mtof(69)
knote2 = kfreq2/110
printk .1, knote2
  endin

Is there a better or more accurate way? The answer or proper opcode/example to do this is probably right in front of me somewhere & likely there is a general way to approach it as I certainly can't be the first to ponder this, but I'm a little lost here.

Scott

Csound mailing list
Csound@listserv.heanet.ie
https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND
Send bugs reports to
        https://github.com/csound/csound/issues
Discussions of bugs and features can be posted here

Hi Scott,
there are the opcods semitone and cent, which will determine the factor 
necessary to change any pitch to go up/down the given semitones or cents. So 
if you specify MIDI notes and hard code the MIDI note of your file, it's easy. 
Say
iFileNote init 69
iDesiredNote init 60
iTones = iDesiredNote - iFileNote ; = -9
iReadFactor init semitone(iTones)
aInput diskin2 Sfile, iReadFactor

I haven't tested it, but I hope you get the picture and can corect any 
haphazard mistakes in the above code. :)

Best wishes and good luck,

Jeanette

-- 
  * Website: http://juliencoder.de - for summer is a state of sound
  * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g
  * Audiobombs: https://www.audiobombs.com/users/jeanette_c
  * GitHub: https://github.com/jeanette-c

You should never try to change me
I can be nobody else
And I like the way I am <3
(Britney Spears)

Csound mailing list
Csound@listserv.heanet.ie
https://listserv.heanet.ie/cgi-bin/wa?A0=CSOUND
Send bugs reports to
        https://github.com/csound/csound/issues
Discussions of bugs and features can be posted here