111 lines
3.4 KiB
C
111 lines
3.4 KiB
C
|
// _____________
|
||
|
|
// _________________
|
||
|
|
// _____/~\___________/\_
|
||
|
|
// ______/\_/\_________/\____
|
||
|
|
// ______/\___/\_______/\______
|
||
|
|
// _____/\_____/\_____/\_______
|
||
|
|
// ____/\_______/\___/\________
|
||
|
|
// __/\_________/\_/\________
|
||
|
|
// /\___________/~\_______
|
||
|
|
// ___________________
|
||
|
|
// _____________
|
||
|
|
//
|
||
|
|
//***************************************************************************//
|
||
|
|
//* *//
|
||
|
|
//* Project : Neural Audio *//
|
||
|
|
//* File : Limiter.c *//
|
||
|
|
//* Description : Limiter *//
|
||
|
|
//* Author(s) : Jeff Thompson *//
|
||
|
|
//* *//
|
||
|
|
//* Copyright (c) Neural Audio Corp. 2008 *//
|
||
|
|
//* *//
|
||
|
|
//***************************************************************************//
|
||
|
|
#include "Neural_THX_Encoders.h"
|
||
|
|
#include <stdlib.h>
|
||
|
|
#include <math.h>
|
||
|
|
#include <float.h>
|
||
|
|
#include "fmod_types.h"
|
||
|
|
|
||
|
|
//***************************************************************************//
|
||
|
|
//* Limiter_INIT(...) *//
|
||
|
|
//***************************************************************************//
|
||
|
|
int Limiter_INIT(float * TempBuffer,
|
||
|
|
Limiter_Struct * pPtr)
|
||
|
|
{
|
||
|
|
pPtr->TempBuffer = TempBuffer;
|
||
|
|
PeakConverter_INIT(0.0f,0.0f,0.0f,0.0f,0,&pPtr->EnvSmoother);
|
||
|
|
return NRLSUR_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
//***************************************************************************//
|
||
|
|
//* Compressor(...) *//
|
||
|
|
//***************************************************************************//
|
||
|
|
int Limiter(float * AudioIn,
|
||
|
|
float * AudioOut,
|
||
|
|
float MaxAudioValue,
|
||
|
|
float Knee, //in dB referenced to zero dB
|
||
|
|
float Ceiling, //in dB referenced to zero dB
|
||
|
|
float RiseTime, //in msec
|
||
|
|
float FallTime, //in msec
|
||
|
|
unsigned int Framesize,
|
||
|
|
unsigned int SampleRate,
|
||
|
|
Limiter_Struct * pPtr)
|
||
|
|
{
|
||
|
|
int n;
|
||
|
|
float fTemp;
|
||
|
|
|
||
|
|
if(Knee > Ceiling) Knee = Ceiling;
|
||
|
|
|
||
|
|
CopyArray(AudioIn,pPtr->TempBuffer,Framesize);
|
||
|
|
|
||
|
|
//First normalize audio
|
||
|
|
if(MaxAudioValue < (float)FLT_EPSILON)
|
||
|
|
MaxAudioValue = (float)FLT_EPSILON;
|
||
|
|
fTemp = 1.0f / MaxAudioValue;
|
||
|
|
ScaleArray(pPtr->TempBuffer,fTemp,Framesize);
|
||
|
|
|
||
|
|
//First convert the audio to the dB domain
|
||
|
|
AbsValue(pPtr->TempBuffer,Framesize);
|
||
|
|
MinClip(pPtr->TempBuffer,(float)FLT_EPSILON,Framesize);
|
||
|
|
MaxClip(pPtr->TempBuffer,1.0f,Framesize);
|
||
|
|
FastLog10_ARRAY(pPtr->TempBuffer,pPtr->TempBuffer,Framesize);
|
||
|
|
ScaleArray(pPtr->TempBuffer,20.0f,Framesize);
|
||
|
|
|
||
|
|
//Smooth the envelope
|
||
|
|
PeakConverter(pPtr->TempBuffer,
|
||
|
|
pPtr->TempBuffer,
|
||
|
|
RiseTime, //in msec
|
||
|
|
FallTime, //in msec
|
||
|
|
-60.0f,
|
||
|
|
0.0f,
|
||
|
|
Framesize,
|
||
|
|
SampleRate,
|
||
|
|
&pPtr->EnvSmoother);
|
||
|
|
|
||
|
|
//Apply the knee and ceiling parameters
|
||
|
|
for(n = 0; n < (int)Framesize; n++){
|
||
|
|
fTemp = pPtr->TempBuffer[n];
|
||
|
|
pPtr->TempBuffer[n] = 0.0f;
|
||
|
|
if(fTemp > Knee){
|
||
|
|
pPtr->TempBuffer[n] = 0.5f * (Knee - fTemp);
|
||
|
|
fTemp = fTemp + pPtr->TempBuffer[n];
|
||
|
|
}
|
||
|
|
if(fTemp > Ceiling){
|
||
|
|
pPtr->TempBuffer[n] += Ceiling - fTemp;
|
||
|
|
fTemp = fTemp + pPtr->TempBuffer[n];
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
//Convert back to linear domain
|
||
|
|
MaxClip(pPtr->TempBuffer,0.0f,Framesize);
|
||
|
|
ScaleArray(pPtr->TempBuffer,0.05f,Framesize);
|
||
|
|
FastPow10_ARRAY(pPtr->TempBuffer,pPtr->TempBuffer,Framesize);
|
||
|
|
|
||
|
|
//Limit the audio signal
|
||
|
|
Multiply2(AudioIn,pPtr->TempBuffer,AudioOut,Framesize);
|
||
|
|
Ceiling = FMOD_POW(10.0f,0.05f*Ceiling) * MaxAudioValue;
|
||
|
|
SaturateArray(AudioOut,Ceiling,Framesize);
|
||
|
|
|
||
|
|
return NRLSUR_OK;
|
||
|
|
}
|