Symbols and numbers in a parameter file have to be limited with
space, tab or return.
The values of a modul (generator, mask etc.) can be distributed over
several lines.
Several moduls can also be written together in one single line.
Symbols (f
, rnd
, mask
, accum
...) can be written in upper case
or lower case letters.
{
<text>
}
The text in braces {}
may contain function table statements, note lists and other score
statements inclusive comments, which should be copied unchanged into
the score file . This prescribed text must be written before any
field desriptions.
Example:
{
f1 0 8193 10 1
f2 0 1024 8 0 512 1 512 0
; tables with sine wave and envelope
}
;
<text>
Comments can be written elsewhere into the parameter file .
They begin with a semicolon ;
and extend to the end of the line.
(
<t1 v1> <t2 v2> <t3 v3> <..> [
ipl
<<val> 
cos

off
>]
) [
<vstart> <vend> [
ipl
<<val> 
cos

off
>] ]
Almost every module in CMask can controlled by a constant or by
time dependend values. The description of variable values is done by
segment functions (also known as breakpoint functions or
polygonals). Such a function have to be written within parenthesis as
a sequence of timevalue pairs or points (<tn vn>
). The function value of
the first point is also valid before its time. The same principle
applies to the last point.
There is a simplified way to write functions that consists of only
one segment lasting from start to end of the field. A simple segment
function have brackets []
and only two numbers  the start and the end value.
Values between the given points will be calculated by linear,
power or cosine function interpolation. The optional interpolation
exponent follows the keyword ipl
. The default for interpolation is
0, that is linear. If ipl
is followed by off
, the
result a step function instead of interpolation.
Interpolation exponents:
exponent 
result 

 
0 
linear (similar to linseg in Csound) 
>0 
slowly rising, fast decaying (convex, similar to expseg in Csound) 
<0 
fast rising. slowly decaying (concave) 

halfcosine interpolation (smooth curve) 

no interpolation (steps, similar to GEN17 in Csound) 
Examples:
(0 3 5 0 8 1) ;3 points {0,3},{5,0} and {8,1} with linear interp.
(0 3 5 0 ipl 1) ;2 points {0,3},{5,0} with concave interp.
[10 50 ipl 2.3] ;2 points {start,10},{end,50} with strong convex int.
[10 50 ipl cos] ;2 points {start,10},{end,50} with smooth interpolation
f
<start time> <end time> <parameter1> <parameter2> ...
A parameter file consists of one or any number of fields. Fields
are comparable to clouds or streams in granular synthesis
systems.
A field describes at least the first 3 parameter of any Csound
instrument: the instrument number, the onset time (or beat) and the
duration. Depending on the structure of the instrument there can be
other parameters.
Every field must have a header that is marked by the letter
f
.
Then follow the start and the end time of the field in seconds.
After the header begins the block with parameter descriptions for
p1, p2, p3
etc.
The field description ends after the last given parameter px
or with a declaration of a next
field.
Fields don't have to be declared in chronological order.
pn
<generator> [<mask>]
[<quantizer>]
[<accumulator>]
[prec <val>]
Each CMask parameter pn
will be described with one or more moduls from the
processing scheme (see above).
n
corresponds to the
numbering in Csound score files p1, p2, p3
etc.
A CMask parameter have to contain at least one of the generators
(const, item, seg, range, rnd,
osc
).
Any subsequent modifying moduls (mask,
quant, accum
) are optional. In dependence on the
choosen generator there only certain modifying moduls allowed.
prec
<val>
The numbers computed by the last modul of every parameter will be
rounded normally to a precision of 5, that is 5 decimal places after
the point. This precision in changeable with the optional prec 
value (0...5).
<val>
defines the
desired number of decimal places for the output, 0 results in
integers, negative values are not allowed.
A generator produces numbers, which may be further processed by a
mask, a quantizer or an accumulator.Currently there are the follwing
generators implemented: const, seg,
range, rnd, osc
and item
.
const
<val>
const generates a constant value
val
.
Possible processing with accum
.
Example:
p1 const 2 ;constant instrument number
item
<mode> <list>
item
reads one number at
a time from list dependend on the mode.
Possible processing with accum
.
access 
mode 
example 

 
cyclic (forward loop) 
cycle 
(1 2 3 4) > 1 2 3 4 1 2 3 4 1 2 3 4 
swinging (forbackward loop) 
swing 
(1 2 3 4) > 1 2 3 4 3 2 1 2 3 4 3 2 
permutations 
heap 
(1 2 3 4) > 3 2 1 4 3 1 4 2 2 3 4 1 
random 
random 
(1 2 3 4) > 4 2 3 3 2 1 3 4 1 2 1 4 



Example:
p4 item heap (400 410 30.3 5000 1222)
;5 different values
seg
<bpf>
seg
reads function
values from the segment function given in bpf
.
Possible processing with quant
and accum.
Example:
p3 seg (0 1 4 .3 6 1)
range
<val1> <val2>
range
generates uniform
distributed random numbers in the range {val1,val2
}.
Possible processing with quant
and accum
.
Example:
p2 range .1 .5 ;rhythms between 0.1
and 0.5 seconds
rnd
<func> [<val1  bpf1> [<val2  bpf2>]]
rnd
produces random
numbers according to a probability distribution func
. Some of the distributions have
optional parameters to describe their shape precisely. The values of
these optional parameters may be constant (val
) or time variant (bpf
).
Possible processing with mask
, quant
and accum
.
Probability distributions:
distribution 
name 
optional parameters 
default 
remarks 

 
uniform 

 


linear 


1.0 
; >0 : decrease 
linear, increasing 

 


triangle 

 


exponential, decreas. 


1.0 
; only values >0 
exponential, increas. 


1.0 
; only values >0 
exponent., bilateral 


1.0 
; only values >0 
gaussian 


0.1 0.5 
; standard deviation 
cauchy 


0.1 0.5 
; spread and mean {0...1} 
beta 


0.1 0.1 
; a and b {0...1} 
weibull 


0.5 2.0 
; s {0...1} and t {>0} 
Example:
p4 rnd gauss (0 .1 10 .6)
.5
osc
<func> [<freq  bpf> [<phs> [<exp>]]]
osc
generates numbers
according to a periodic function func
in dependence on a constant or
variable frequency freq
and
an optional phase phs
.
Possible processing with mask
, quant
and accum
.
Periodic functions:
function 
name 
optional parameters 
default 
remarks 

 
sine 


1 0 
;frequenz in cps, phase {0...1} 
cosine 


1 0 

square 


1 0 

triangle 


1 0 

saw, increasing 


1 0 

saw, decreasing 


1 0 

power function, 


1 0 0 
;frequenz, phase, exponent 
power function, 


1 0 0 
;frequenz, phase, exponent 
Example:
p4 osc sin (0 2 3 .5 ipl 1) ;from 2 to
0.5 Hz falling frequency
A modifier processes the numbers which was generated by a
preceeding generator or another modifier.
All modifying moduls are optional, but there is only one possible
order (see the processing scheme above).
The implemented modifiers are: mask
, quant
and accum
.
mask
<low  bpf> <high  bpf> [map <exp>]
The values generated by rnd
or osc
can can be mapped onto a time
dependend range  the tendendency mask.
Both low and high boundaries may be constant or time variant
(bpf
).
The mapping process itself depends on the optional map
exponent: Values which was produced
by rnd
or osc
are always in the range {0...1}.
Within a mask they will now transformed by a (nonlinear) function:
The default exponent is 0, this results in a linear
transformation.
Positive exponents result in a power function. For example: an
exponent 1 makes the squares of the input numbers, 0.5 will be 0.25,
0.3 will be 0.09, that is, all values gets smaller (except 0 and
1).
Negative exponents result in a root function. For example: an
exponent 1 makes the square root of the input numbers, 0.5 will be
0.707, 0.3 will be 0.547, that is, all values gets larger (except 0
and 1).
Example:
p4 rnd uni
mask 50 (2 100 10 200) ;lower limit 50, upper limit from 100 to 200
quant
<q  bpf> [<s  bpf> [<o  bpf>]]
A quantizer attracts the results of the preceeding modul onto a
quantization grid q
. The
optional strength s
{0...1}
(default 1) specifies to which extent the grid takes effect (1 is
total quantization, 0 is no quantization at all). The optional offset
o
(default 0) shifts the
whole grid by the given amount. Each of the 3 parameters may be
constant or time variant (bpf
).
Example:
p4 range 100 200
quant 20 [0 1] ; dynam. quantization to a grid > 100,120,140,160,180,200
accum
<mode> [<low  bpf> <high  bpf>] [init <exp>]
The accumulator continuously sums all its input values to an
inital value init
. The
inital value is optional and has a default value of 0. In order to
restrict the sum to a certain range it is possible to define lower
and upper limits similar to tendency masks.
The accumulators behavior near by the limits can be determined by one of three limiting modes:
method 
mode 
parameter 

 
without any limiting 


with limiting 


with limiting and reflection 


with cyclic closed limits 


Example:
p4 range 10 10
akkum mirror 100 300 init 200