third_party/flac/include/share/replaygain_synthesis.h

/* replaygain_synthesis - Routines for applying ReplayGain to a signal
 * Copyright (C) 2002-2009  Josh Coalson
 * Copyright (C) 2011-2022  Xiph.Org Foundation
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
 */

#ifndef FLAC__SHARE__REPLAYGAIN_SYNTHESIS_H
#define FLAC__SHARE__REPLAYGAIN_SYNTHESIS_H

#include <stdlib.h> /* for size_t */
#include "FLAC/format.h"

#define FLAC_SHARE__MAX_SUPPORTED_CHANNELS FLAC__MAX_CHANNELS

typedef enum {
  NOISE_SHAPING_NONE = 0,
  NOISE_SHAPING_LOW = 1,
  NOISE_SHAPING_MEDIUM = 2,
  NOISE_SHAPING_HIGH = 3
} NoiseShaping;

typedef struct {
  const float* FilterCoeff;
  FLAC__uint64 Mask;
  double Add;
  float Dither;
  float ErrorHistory[FLAC_SHARE__MAX_SUPPORTED_CHANNELS]
                    [16]; /* 16th order Noise shaping */
  float DitherHistory[FLAC_SHARE__MAX_SUPPORTED_CHANNELS][16];
  int LastRandomNumber[FLAC_SHARE__MAX_SUPPORTED_CHANNELS];
  unsigned LastHistoryIndex;
  NoiseShaping ShapingType;
} DitherContext;

void FLAC__replaygain_synthesis__init_dither_context(DitherContext* dither,
                                                     int bits,
                                                     int shapingtype);

/* scale = (float) pow(10., (double)replaygain * 0.05); */
size_t FLAC__replaygain_synthesis__apply_gain(FLAC__byte* data_out,
                                              FLAC__bool little_endian_data_out,
                                              FLAC__bool unsigned_data_out,
                                              const FLAC__int32* const input[],
                                              uint32_t wide_samples,
                                              uint32_t channels,
                                              const uint32_t source_bps,
                                              const uint32_t target_bps,
                                              const double scale,
                                              const FLAC__bool hard_limit,
                                              FLAC__bool do_dithering,
                                              DitherContext* dither_context);

#endif