flooper

flooper — Function-table-based crossfading looper.

Description

This opcode reads audio from a function table and plays it back in a loop with user-defined start time, duration and crossfade time. It also allows the pitch of the loop to be controlled, including reversed playback. It accepts non-power-of-two tables, such as deferred-allocation GEN01 tables.

Syntax

asig flooper kamp, kpitch, istart, idur, ifad, ifn

Initialization

istart -- loop start pos in seconds

idur -- loop duration in seconds

ifad -- crossfade duration in seconds

ifn -- function table number, generally created using GEN01

Performance

asig -- output sig

kamp -- amplitude control

kpitch -- pitch control (transposition ratio); negative values play the loop back in reverse

Examples

Example 260. 

aout flooper 16000, 1, 1, 4, 0.05, 1  ; loop starts at 1 sec, for 4 secs, 0.05 crossfade
     out     aout


The example above shows the basic operation of flooper. Pitch can be controlled at the k-rate, as well as amplitude. The example assumes table 1 to contain at least 5.05 seconds of audio (4 secs loop duration, starting 1 sec into the table, using 0.05 secs after the loop end for the crossfade).

Here is another example of the flooper opcode. It uses the file flooper.csd and fox.wav.

Example 261. 

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

<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
-odac     ;;;realtime audio out
;-iadc    ;;;uncomment -iadc if realtime audio input is needed too
; For Non-realtime ouput leave only the line below:
; -o flooper.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

sr = 44100
ksmps = 32
nchnls = 2
0dbfs  = 1

instr 1

kpitch	line	1, p3, .9 ;lower pitch a bit during the note
aout	flooper	.9, kpitch, 1, .53, 0.05, 1  ; loop starts at 1 sec, for .53 secs, 0.05 crossfade
	outs	aout, aout

endin
</CsInstruments>
<CsScore>
;table size is deferred,
; and format taken from the soundfile header
f 1 0 0 1 "fox.wav" 0 0 0

i 1 0 8.2
e
</CsScore>
</CsoundSynthesizer>


Credits

Author: Victor Lazzarini
April 2005

New plugin in version 5

April 2005.