winamp/Src/vlb/tns.h

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2024-09-24 12:54:57 +00:00
/* $Header: /cvs/root/winamp/vlb/tns.h,v 1.1 2009/04/28 20:21:11 audiodsp Exp $ */
/***************************************************************************\
*
* Copyright 2000-2002 Dolby Laboratories, Inc. All Rights
* Reserved. Do not copy. Do not distribute.
* Confidential information.
*
* (C) copyright Fraunhofer - IIS (1998)
* All Rights Reserved
*
* filename: tns.h
* project : MPEG-2 AAC Decoder
* contents/description: temporal noise shaping
*
\***************************************************************************/
#ifndef __TNS_H__
#define __TNS_H__
#include "bitsequence.h"
class CChannelInfo ;
class CBlock ;
/** Temporal Noise Shaping.
This class represents the temporal noise shaping tool for decoding and
applying tns filter data to the spectral coefficients of the current block.
TNS is a profile-dependent tool and the CTns implementation follows the
Read()/Apply() convention used for all tools.
*/
class CTns
{
public :
CTns () ;
~CTns () ;
void Read (const CChannelInfo &info, CDolbyBitStream &bs) ;
void Apply (const CChannelInfo &info, CBlock &spectrum) ;
enum
{
MaximumWindows = 8,
MaximumBands = 49,
MaximumOrder = 31,
MaximumFilters = 3
} ;
protected :
CVLBBitSequence m_TnsDataPresent ;
class CFilter
{
public :
int m_StartBand ;
int m_StopBand ;
int m_Direction ;
int m_Resolution ;
int m_Order ;
int m_Coeff [MaximumOrder] ;
} ;
int m_NumberOfFilters [MaximumWindows] ;
CFilter m_Filter [MaximumWindows][MaximumFilters] ;
int Minimum (int a, int b, int c)
{
int t = (a < b ) ? a : b ;
return (t < c) ? t : c ;
}
void DecodeCoefficients (CFilter &filter, float *a) ;
void Filter (float *spec, int size, int inc, float *lpc, int order) ;
} ;
#endif