swresample_internal.h

/*
 * Copyright (C) 2011-2013 Michael Niedermayer (michaelni@gmx.at)
 *
 * This file is part of libswresample
 *
 * libswresample 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.
 *
 * libswresample 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 libswresample; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef SWR_INTERNAL_H
#define SWR_INTERNAL_H

#include "swresample.h"
#include "libavutil/channel_layout.h"
#include "config.h"

#define SWR_CH_MAX 64

#define SQRT3_2      1.22474487139158904909  /* sqrt(3/2) */

#define NS_TAPS 20

#if ARCH_X86_64
typedef int64_t integer;
#else
typedef int integer;
#endif

typedef void (mix_1_1_func_type)(void *out, const void *in, void *coeffp, integer index, integer len);
typedef void (mix_2_1_func_type)(void *out, const void *in1, const void *in2, void *coeffp, integer index1, integer index2, integer len);

typedef void (mix_any_func_type)(uint8_t **out, const uint8_t **in1, void *coeffp, integer len);

typedef struct AudioData{
    uint8_t *ch[SWR_CH_MAX];    ///< samples buffer per channel
    uint8_t *data;              ///< samples buffer
    int ch_count;               ///< number of channels
    int bps;                    ///< bytes per sample
    int count;                  ///< number of samples
    int planar;                 ///< 1 if planar audio, 0 otherwise
    enum AVSampleFormat fmt;    ///< sample format
} AudioData;

struct DitherContext {
    int method;
    int noise_pos;
    float scale;
    float noise_scale;                              ///< Noise scale
    int ns_taps;                                    ///< Noise shaping dither taps
    float ns_scale;                                 ///< Noise shaping dither scale
    float ns_scale_1;                               ///< Noise shaping dither scale^-1
    int ns_pos;                                     ///< Noise shaping dither position
    float ns_coeffs[NS_TAPS];                       ///< Noise shaping filter coefficients
    float ns_errors[SWR_CH_MAX][2*NS_TAPS];
    AudioData noise;                                ///< noise used for dithering
    AudioData temp;                                 ///< temporary storage when writing into the input buffer isn't possible
    int output_sample_bits;                         ///< the number of used output bits, needed to scale dither correctly
};