median — A median filter, a variant FIR lowpass filter.


Implementation of a median filter.


ares median asig, ksize, imaxsize [, iskip]


imaxsize -- the maximun size of the window used to select the data.

iskip -- initial disposition of internal data space. A zero value will clear the space; a non-zero value will allow previous information to remain. The default value is 0.


asig -- input signal to be filtered

ksize -- size of the window over which the input is to be filtered. It must not exceed the maximum window size; if it does it is truncated.

median is a simple filter that retuns the median value of the last ksize values. It has a lowpass action. The efficiency decreases as the window size increases.


Here is an example of the median opcode. It uses the file median.csd.

Example 599. Example of the median opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.


sr = 44100
kr = 441
ksmps = 100
nchnls = 1

instr 1
  a1  oscil  30000, 10, 1
  a2  median a1, 5, 8
  out a2

f1 0 4096 10 1
i 1 0 0.1 



See also

Standard filters: Variant FIR lowpass filter


Author: John ffitch
University of Bath
May 2010

New in Csound version 5.13