Interchangeable microtonal text format (IMT) - proposal.

Here is a first idea for a text file format to be easily read by
microtonal programs and saved, and to specify microtonal pitches
and timings:

Requirements - must be easy to read and to save. Must be easily
convertible into Midi and also into C-sound. Must be possible to
save it directly from a performance in real time, so that one
records note ons and note offs as separate events.

Must also be able to quickly convert into it from a format that 
specifies each note by the start time and duration only, with no note offs.

Must be able to specify pitches by scale degrees only, or by cents,
ratios, or herz values.

Default scale I suppose 12-et and default 1o1 middle c, but then
you can specify those.

A pentatonic j.i. tune  might begin:

scale 1/1 9/8 5/4 3/2 16/5 16/9 2/1
1o1 440.0

time 0.0
notes 1:0=1.0 1:2=1.0 2:3=1.0
time 1.0

here in 1:0=1.0

1: means play the note in part 1 where by default one need make
   no distinction between parts and instruments - instrument n 
   plays in part n
0 means play scale degree 0. Here you can also use
  decimal point for cents, ratio with '/' for ratio, or herz
  using z as prefix, e.g. z440 to play  440 herz.
=1.0 = note lasts for 1.0 seconds

time 1.0 sets the current time for what follows.

For real time recording the same thing is done as:

time 0.0
notes_on 1:0 1:2 2:3
time 1.0
notes_off 1:0 1:2 2:3

Here something that raises a question - how do you recognise a note
off? Maybe that it is the same pitch to within a given tolerance
and the same instrument number as the note on.

Conversion between the two formats is still tricky - but
maybe one could do a utility to do it. It just needs to read
the notes_on, notes_off, time, and notes lines and can
leave everything else unchanges.

Also would have an optional

arpeggio 0 2 4 7 9 12
so that from then on the degrees refer to notes
in the arpeggio rather than the scale, then
arpeggio(0) resets it to follow the scale again.

I think that covers all the essentials of playing notes
- one then needs to think about effects and pitch glides
and so on, and how to do those.

Maybe

glide 0 12 0.5 100 = glide from scale degree 0 to 12 in 0.5 seconds
with a suggested resolution of 100 pitch increments.

Each instruction has to start a new line, and a program that reads it
ignores the rest of the line if it doesn't recognise the instruction that
starts it.

Any tokens after the first one that begin with anything except for 0, 1, .. 9
are treated as comments, so you can write.

glide from 0 to 12 time 0.5 steps 100

The program reading it will just read the word glide at the beginning to know 
what it is then only the numbers after that 

String comparison takes
time while just testing to see if a token begins with 0 to 9 is very fast
indeed, in c it can be done in a single switch statement which is
very fast indeed.

switch(c)
{
 case '0':
 case '1':
...
 case '9':
  // read the next expected value
  break;
 default:
  // ignore it
}

Also as in Scala, all lines begining with an '!' as comments.


If you use decimal point instead of a scale degree,
reads it as cents inteval from the 1o1
(ignore the current scale) If it has a '/', the value is a ratio.
To play a particular herz value prefix it with z.

so:

notes 1:7/6=1.0 1:702.0=1.0 1:z660=1.0
are examples of these other three file formats -
ratio, cents, herz.

If the number has a '/' in it, it is read as a ratio 
so you can specify decimal point numbers by appending
/1. E.g. 1.5/1 is the same as 3/2, and _not_ 1.5 cents.


Have parts too:

By default instrument n plays in part n.

To change that:

Parts 1:3 2:3 3:6

Part 1 plays instrument 3, so does part 2. Part 3 plays instrument 6

Then after that when you have

notes 1:0=1.0 

it now means part 1 plays degree 0 for 1 second, so i.e. instrument 3 as that
is now the instrument for part 1, using whatever
effects have been assigned to part 1.

This will make conversion from midi easier and also generally a useful
feature to have.

Controllers etc: can do

midi_controller 10 (pan) part 1 value 64

to set pan for part 1 to 64

that kind of thing.

Just an idea.