The Alternative Csound Reference Manual
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# dispfft

displayfft -- Displays the Fourier Transform of an audio or control signal.

## Description

These units will print orchestra init-values, or produce graphic display of orchestra control signals and audio signals. Uses X11 windows if enabled, else (or if -g flag is set) displays are approximated in ASCII characters.

## Syntax

dispfft xsig, iprd, iwsiz [, iwtyp] [, idbout] [, iwtflg]

## Initialization

iprd -- the period of display in seconds.

iwsiz -- size of the input window in samples. A window of iwsiz points will produce a Fourier transform of iwsiz/2 points, spread linearly in frequency from 0 to sr/2. iwsiz must be a power of 2, with a minimum of 16 and a maximum of 4096. The windows are permitted to overlap.

iwtyp (optional, default=0) -- window type. 0 = rectangular, 1 = Hanning. The default value is 0 (rectangular).

idbout (optional, default=0) -- units of output for the Fourier coefficients. 0 = magnitude, 1 = decibels. The default is 0 (magnitude).

iwtflg (optional, default=0) -- wait flag. If non-zero, each display is held until released by the user. The default value is 0 (no wait).

## Performance

dispfft -- displays the Fourier Transform of an audio or control signal (asig or ksig) every iprd seconds using the Fast Fourier Transform method.

## Examples

Here is an example of the dispfft opcode. It uses the files dispfft.orc, dispfft.sco and beats.wav.

Example 1. Example of the dispfft opcode.

    /* dispfft.orc */
    ; Initialize the global variables.
    sr = 44100
    kr = 4410
    ksmps = 10
    nchnls = 1

    ; Instrument #1.
    instr 1
      asig soundin "beats.wav"
      dispfft asig, 1, 512
      out asig
    endin
    /* dispfft.orc */

    /* dispfft.sco */
    ; Play Instrument #1 for three seconds.
    i 1 0 3
    e
    /* dispfft.sco */

## See Also

display, print

## Credits

Comments about the inprds parameter contributed by Rasmus Ekman.

Example written by Kevin Conder.

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