scummvm/sound/resample.h

94 lines
2.8 KiB
C++

/* ScummVM - Scumm Interpreter
* Copyright (C) 2001-2003 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.
*
* $Header$
*
*/
#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). */
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(AudioInputStream &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