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- // Copyright 2006, Thomas Scott Stillwell
- // All rights reserved.
- //
- //Redistribution and use in source and binary forms, with or without modification, are permitted
- //provided that the following conditions are met:
- //
- //Redistributions of source code must retain the above copyright notice, this list of conditions
- //and the following disclaimer.
- //
- //Redistributions in binary form must reproduce the above copyright notice, this list of conditions
- //and the following disclaimer in the documentation and/or other materials provided with the distribution.
- //
- //The name of Thomas Scott Stillwell may not be used to endorse or
- //promote products derived from this software without specific prior written permission.
- //
- //THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
- //IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
- //FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
- //BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
- //(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- //PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
- //STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
- //THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- desc:peak-eating limiter
-
- slider1:0.0<-30.0,0.0,0.1>Threshold
- slider2:-0.1<-20.0,0.0,0.1>Ceiling
- slider3:2.0<0,6.0,0.01>Soft clip (dB)
- //slider4:10<3,20,0.1>Soft clip ratio
-
- @init
- pi = 3.1415926535;
- log2db = 8.6858896380650365530225783783321; // 20 / ln(10)
- db2log = 0.11512925464970228420089957273422; // ln(10) / 20
-
- @slider
- thresh=exp(slider1 * db2log);
- threshdb=slider1;
- ceiling=exp(slider2 * db2log);
- ceildb=slider2;
- makeup=exp((ceildb-threshdb) * db2log);
- makeupdb=ceildb-threshdb;
- sc = -slider3;
- scv = exp(sc * db2log);
- sccomp = exp(-sc * db2log);
- peakdb = ceildb+25;
- peaklvl = exp(peakdb * db2log);
- scratio = slider4;
- scmult = abs((ceildb - sc) / (peakdb - sc));
-
- @sample
- peak=max(abs(spl0),abs(spl1));
- spl0=spl0*makeup;
- spl1=spl1*makeup;
- sign0 = sign(spl0);
- sign1 = sign(spl1);
- abs0=abs(spl0);
- abs1=abs(spl1);
- overdb0 = 2.08136898 * log(abs0) * log2db - ceildb;
- overdb1 = 2.08136898 * log(abs1) * log2db - ceildb;
- abs0 > scv ? (
- spl0=sign0*(scv + exp(overdb0*scmult)*db2log);
- );
- abs1 > scv ? (
- spl1=sign1*(scv + exp(overdb1*scmult)*db2log);
- );
-
- spl0=min(ceiling,abs(spl0))*sign(spl0);
- spl1=min(ceiling,abs(spl1))*sign(spl1);
-