190 lines
8.4 KiB
C
190 lines
8.4 KiB
C
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// _____________
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// _________________
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// _____/~\___________/\_
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// ______/\_/\_________/\____
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// ______/\___/\_______/\______
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// _____/\_____/\_____/\_______
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// ____/\_______/\___/\________
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// __/\_________/\_/\________
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// /\___________/~\_______
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// ___________________
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// _____________
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//
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//***************************************************************************//
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//* *//
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//* Project : Neural Audio - THX *//
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//* File : Neural_THX_522_Encode.c *//
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//* Description : Neural Surround Downmix implementation *//
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//* Author(s) : Jeff Thompson *//
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//* *//
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//* Copyright (c) Neural Audio Corp. 2008 *//
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//* *//
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//***************************************************************************//
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#include "Neural_THX_Encoders.h"
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#include <stdlib.h>
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//***************************************************************************//
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//* Neural_THX_522_Encode_INIT(...) *//
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//***************************************************************************//
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int Neural_THX_522_Encode_INIT(unsigned int Framesize,
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unsigned int ChanConfig,
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unsigned int SampleRate,
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Neural_THX_522_Encode_Struct * pParams)
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{
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//Forward and inverse overlapped FFT's
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FFT_Overlapped_Stereo_INIT(&pParams->FFTSourceLR,pParams->TempBuffer0,pParams->TempBuffer1,NEURAL_FRAMESIZE);
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FFT_Overlapped_INIT(&pParams->FFTSourceC,pParams->TempBuffer0,pParams->TempBuffer1,NEURAL_FRAMESIZE);
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FFT_Overlapped_Stereo_INIT(&pParams->FFTSourceLsRs,pParams->TempBuffer0,pParams->TempBuffer1,NEURAL_FRAMESIZE);
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IFFT_Overlapped_Stereo_INIT(&pParams->InvFFTDownmixLR,pParams->TempBuffer0,pParams->TempBuffer1,NEURAL_FRAMESIZE);
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//Initialize phase shifts
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FreqDomain_PhaseShift_INIT(-22.5f,NEURAL_FRAMESIZE,&pParams->PhaseShift_L);
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FreqDomain_PhaseShift_INIT(+22.5f,NEURAL_FRAMESIZE,&pParams->PhaseShift_R);
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FreqDomain_PhaseShift_INIT(-90.0f,NEURAL_FRAMESIZE,&pParams->PhaseShift_Ls);
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FreqDomain_PhaseShift_INIT(+90.0f,NEURAL_FRAMESIZE,&pParams->PhaseShift_Rs);
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LR4_LP_INIT(&pParams->LFE_LP);
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//Init final limiters
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Limiter_INIT(pParams->TempBuffer0,&pParams->FinalLimiterL);
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Limiter_INIT(pParams->TempBuffer0,&pParams->FinalLimiterR);
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return NRLSUR_OK;
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}
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//***************************************************************************//
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//* Neural_THX_522_Encode(...) *//
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//***************************************************************************//
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int Neural_THX_522_Encode(float * PtrInL,
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float * PtrInR,
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float * PtrInC,
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float * PtrInLFE,
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float * PtrInLs,
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float * PtrInRs,
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float * PtrOutL,
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float * PtrOutR,
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THX_bool UseFinalLimiting,
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float LFE_Cutoff,
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unsigned int Framesize,
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unsigned int ChanConfig,
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unsigned int SampleRate,
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Neural_THX_522_Encode_Struct * pParams)
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{
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//Neural Surround Downmix
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//***********************************************************
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//***** Low-pass filter the LFE channel (if selected) *****
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//***********************************************************
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if(LFE_Cutoff > 40.0f && LFE_Cutoff < 200.0f){
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LR4_LP(PtrInLFE,PtrInLFE,LFE_Cutoff,NEURAL_FRAMESIZE,SampleRate,&pParams->LFE_LP);
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}
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//First sum LFE channel into Center channel
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Add2(PtrInC,PtrInLFE,PtrInC,NEURAL_FRAMESIZE);
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//****************************************************************************************************
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//***** Begin downmix by transforming all signals to frequency domain and performing phase shift *****
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//****************************************************************************************************
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//Convert all input channels to freq domain
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//L-R channels
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FFT_Overlapped_Stereo(PtrInL,pParams->Input_RealL,pParams->Input_ImagL,
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PtrInR,pParams->Input_RealR,pParams->Input_ImagR,
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NEURAL_FRAMESIZE,&pParams->FFTSourceLR);
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//C channel
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FFT_Overlapped(PtrInC,pParams->Input_RealC,pParams->Input_ImagC,
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NEURAL_FRAMESIZE,&pParams->FFTSourceC);
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//Ls-Rs channels
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FFT_Overlapped_Stereo(PtrInLs,pParams->Input_RealLs,pParams->Input_ImagLs,
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PtrInRs,pParams->Input_RealRs,pParams->Input_ImagRs,
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NEURAL_FRAMESIZE,&pParams->FFTSourceLsRs);
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//Phase shift L channel
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FreqDomain_PhaseShift(pParams->Input_RealL,pParams->Input_ImagL,
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pParams->Input_RealL,pParams->Input_ImagL,
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-22.5f,NEURAL_FRAMESIZE,SampleRate,&pParams->PhaseShift_L);
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//Phase shift R channel
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FreqDomain_PhaseShift(pParams->Input_RealR,pParams->Input_ImagR,
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pParams->Input_RealR,pParams->Input_ImagR,
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+22.5f,NEURAL_FRAMESIZE,SampleRate,&pParams->PhaseShift_R);
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//Phase shift Ls channel
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FreqDomain_PhaseShift(pParams->Input_RealLs,pParams->Input_ImagLs,
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pParams->Input_RealLs,pParams->Input_ImagLs,
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-90.0f,NEURAL_FRAMESIZE,SampleRate,&pParams->PhaseShift_Ls);
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//Phase shift Rs channel
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FreqDomain_PhaseShift(pParams->Input_RealRs,pParams->Input_ImagRs,
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pParams->Input_RealRs,pParams->Input_ImagRs,
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+90.0f,NEURAL_FRAMESIZE,SampleRate,&pParams->PhaseShift_Rs);
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//Scale center and lfe channels by -3dB
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ScaleArray(pParams->Input_RealC,(float)MINUS_3DB,NEURAL_FRAMESIZE);
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ScaleArray(pParams->Input_ImagC,(float)MINUS_3DB,NEURAL_FRAMESIZE);
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//Add center and lfe channels to left/right phase shifted channels
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//L channel
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Add2(pParams->Input_RealL,pParams->Input_RealC,pParams->Downmix_RealL,NEURAL_FRAMESIZE);
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Add2(pParams->Input_ImagL,pParams->Input_ImagC,pParams->Downmix_ImagL,NEURAL_FRAMESIZE);
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//R channel
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Add2(pParams->Input_RealR,pParams->Input_RealC,pParams->Downmix_RealR,NEURAL_FRAMESIZE);
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Add2(pParams->Input_ImagR,pParams->Input_ImagC,pParams->Downmix_ImagR,NEURAL_FRAMESIZE);
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//***********************************************************
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//***** Combine the front channels with the surrounds *****
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//***********************************************************
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ScaleArray(pParams->Input_RealLs,(float)CROSSSHARENORM,NEURAL_FRAMESIZE);
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ScaleArray(pParams->Input_ImagLs,(float)CROSSSHARENORM,NEURAL_FRAMESIZE);
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ScaleArray(pParams->Input_RealRs,(float)CROSSSHARENORM,NEURAL_FRAMESIZE);
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ScaleArray(pParams->Input_ImagRs,(float)CROSSSHARENORM,NEURAL_FRAMESIZE);
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Add2(pParams->Downmix_RealL,pParams->Input_RealLs,pParams->Downmix_RealL,NEURAL_FRAMESIZE);
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Add2(pParams->Downmix_ImagL,pParams->Input_ImagLs,pParams->Downmix_ImagL,NEURAL_FRAMESIZE);
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Add2(pParams->Downmix_RealR,pParams->Input_RealRs,pParams->Downmix_RealR,NEURAL_FRAMESIZE);
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Add2(pParams->Downmix_ImagR,pParams->Input_ImagRs,pParams->Downmix_ImagR,NEURAL_FRAMESIZE);
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CopyArray(pParams->Input_RealLs,pParams->TempBuffer0,NEURAL_FRAMESIZE);
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ScaleArray(pParams->TempBuffer0,-CROSSSHARECONSTANT,Framesize);
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Add2(pParams->Downmix_RealR,pParams->TempBuffer0,pParams->Downmix_RealR,NEURAL_FRAMESIZE);
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CopyArray(pParams->Input_ImagLs,pParams->TempBuffer0,NEURAL_FRAMESIZE);
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ScaleArray(pParams->TempBuffer0,-CROSSSHARECONSTANT,Framesize);
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Add2(pParams->Downmix_ImagR,pParams->TempBuffer0,pParams->Downmix_ImagR,NEURAL_FRAMESIZE);
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CopyArray(pParams->Input_RealRs,pParams->TempBuffer0,NEURAL_FRAMESIZE);
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ScaleArray(pParams->TempBuffer0,-CROSSSHARECONSTANT,Framesize);
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Add2(pParams->Downmix_RealL,pParams->TempBuffer0,pParams->Downmix_RealL,NEURAL_FRAMESIZE);
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CopyArray(pParams->Input_ImagRs,pParams->TempBuffer0,NEURAL_FRAMESIZE);
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ScaleArray(pParams->TempBuffer0,-CROSSSHARECONSTANT,Framesize);
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Add2(pParams->Downmix_ImagL,pParams->TempBuffer0,pParams->Downmix_ImagL,NEURAL_FRAMESIZE);
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//***********************************************************
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//***** Inverse filterbank back to time signals *****
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//***********************************************************
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IFFT_Overlapped_Stereo(pParams->Downmix_RealL,pParams->Downmix_ImagL,PtrOutL,
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pParams->Downmix_RealR,pParams->Downmix_ImagR,PtrOutR,
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NEURAL_FRAMESIZE,&pParams->InvFFTDownmixLR);
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if(UseFinalLimiting){
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//Perform final limiting on the output signals
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Limiter(PtrOutL,PtrOutL,
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(float)AUDIO_VAL_MAX,
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-6.0f,-0.1f,
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0.0f,500.0f,
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NEURAL_FRAMESIZE,SampleRate,&pParams->FinalLimiterL);
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Limiter(PtrOutR,PtrOutR,
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(float)AUDIO_VAL_MAX,
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-6.0f,-0.1f,
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0.0f,500.0f,
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NEURAL_FRAMESIZE,SampleRate,&pParams->FinalLimiterR);
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}
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//That's all folks
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SaturateArray(PtrOutL,(float)AUDIO_VAL_MAX,NEURAL_FRAMESIZE);
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SaturateArray(PtrOutR,(float)AUDIO_VAL_MAX,NEURAL_FRAMESIZE);
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return NRLSUR_OK;
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}
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