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resample.h

/* ScummVM - Scumm Interpreter
 * Copyright (C) 2001-2004 The ScummVM project
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.

 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * $Header: /cvsroot/scummvm/scummvm/sound/Attic/resample.h,v 1.7 2004/01/06 12:45:33 fingolfin Exp $
 *
 */

#ifndef SOUND_RESAMPLE_H
#define SOUND_RESAMPLE_H

#include "sound/rate.h"


/* this Float MUST match that in filter.c */
#define Float double/*float*/

// From resample's stddef.h
typedef int16     HWORD;
typedef uint16    UHWORD;
typedef int32     WORD;
typedef uint32    UWORD;

#define MAX_HWORD (32767)
#define MIN_HWORD (-32768)


#define MAXNWING   8192


/* Private data for Lerp via LCM file */
typedef struct resamplestuff {
      double Factor;     /* Factor = Fout/Fin sample rates */
      int quadr;        /* non-zero to use qprodUD quadratic interpolation */


      long Nq;

      long dhb;

      long a, b;        /* gcd-reduced input,output rates     */
      long t;           /* Current time/pos for exact-coeff's method */

      long Xh;          /* number of past/future samples needed by filter      */
      long Xoff;        /* Xh plus some room for creep  */
      long Xread;       /* X[Xread] is start-position to enter new samples */
      long Xp;          /* X[Xp] is position to start filter application       */
      long Xsize, Ysize;  /* size (Floats) of X[],Y[]   */
      long Yposition;         /* FIXME: offset into Y buffer */
      Float *X, *Y;      /* I/O buffers */
} *resample_t;


/** High quality rate conversion algorithm, based on SoX (http://sox.sourceforge.net). */
00068 class ResampleRateConverter : public RateConverter {
protected:
      resamplestuff rstuff;

      int quadr;        /* non-zero to use qprodUD quadratic interpolation */

    UHWORD LpScl; /* Unity-gain scale factor */
    UHWORD Nwing; /* Filter table size */
    UHWORD Nmult; /* Filter length for up-conversions */
    HWORD Imp[MAXNWING];            /* Filter coefficients */
    HWORD ImpD[MAXNWING];     /* ImpD[n] = Imp[n+1]-Imp[n] */
      
      HWORD *X1, *Y1;
      HWORD *X2, *Y2;
      
      UWORD Time;       /* Current time/pos in input sample */

public:
      ResampleRateConverter(st_rate_t inrate, st_rate_t outrate, int quality);
      ~ResampleRateConverter();
      virtual int flow(AudioStream &input, st_sample_t *obuf, st_size_t osamp, st_volume_t vol);
      virtual int drain(st_sample_t *obuf, st_size_t osamp, st_volume_t vol);
};


#endif

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