82 lines
2.5 KiB
C++
82 lines
2.5 KiB
C++
/* $Header: /cvs/root/winamp/vlb/audio_io_dsp.h,v 1.1 2009/04/28 20:21:08 audiodsp Exp $ */
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/***************************************************************************\
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*
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* Copyright 2000-2002 Dolby Laboratories, Inc. All Rights
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* Reserved. Do not copy. Do not distribute.
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* Confidential information.
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*
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* (C) copyright Fraunhofer - IIS (1998)
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* All Rights Reserved
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*
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* filename: audio_io_dsp.h
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* project : MPEG-2 AAC Decoder
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* contents/description: Audio DSP processing header file
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*
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\***************************************************************************/
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#ifndef __AUDIO_IO_DSP_H__
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#define __AUDIO_IO_DSP_H__
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#define CLIPDLY 10
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#define CLIPNORM (1.0/CLIPDLY)
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#define DLYBUFSZ 128
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#define PMAXF 32767.0f
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#define PMAXFM1 (PMAXF-1)
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#define NMAXF -32768.0f
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#define MAXCHANNELS 2
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#define NSAMPRATE 12
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#define XLIMDELAY 5 // delay is 1/5 second before decay stage of clip delay return segment.
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#define NSCALETAB 33
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#define PEAKLIMIT (3.16*PMAXF) // Allows for 10 dB of smoothed limiting. Any overshoot greater
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// than 10 dB is hard limited.
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#define PEAKLIMITM1 (PEAKLIMIT-1)
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#define INTERP_CORRECTION_FACT 0.013 // compensates for error between actual inverse and estimated inverse
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// in scaletab table.
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#define CX_LIMSCALE ((NSCALETAB-1)/(PEAKLIMIT-PMAXF))
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typedef struct {
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short index;
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short delay;
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short bufsize;
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float *bufptr;
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} DLY_VARS;
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typedef struct {
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short dcy_count;
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float dcy_samp;
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} SMOOTH_VARS;
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class AudioIODSP{
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private:
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DLY_VARS **hsClipDly;
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SMOOTH_VARS **hsSmoothVars;
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int iNChannels;
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bool bHardClip;
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float *pfDlyBuf;
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float fPrevDlyBuf[MAXCHANNELS][CLIPDLY];
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float fPrevClipScale[MAXCHANNELS];
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short initLimitCnt; // Amount of time to delay before decaying the limiter scaling value.
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float dcyDelta; // Dcy_delta is the amount to attenuate the limiter scaling value
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// on each call to CalcAtten().
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unsigned int uiSampRate;
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float AudioIODSP::CalcAtten(SMOOTH_VARS *smoothvars, float fMaxSamp, float thresh);
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public:
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short *pshOutBuf;
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AudioIODSP(int _iNChannels, unsigned int _uiSampRate = 0);
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~AudioIODSP();
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void Float_to_Short_Clip(float **fInput, short *sOutput, int iLength, int grpIndex);
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void Float_to_Int(float **fInput, int *iOutput, int iLength, int grpIndex,
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int bitResolution);
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void ApplyLimiter(float **fBuffer, int iLength, int grpIndex);
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void SetSamplingRate(unsigned int _uiSampRate);
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};
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#endif /* __AUDIO_IO_DSP_H__ */
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