/*

 * Copyright (C) 2012-2013 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

 */

#include "libavutil/avassert.h"

#include "libavutil/mem.h"

#include "swresample_internal.h"

#include "noise_shaping_data.c"

int swri_get_dither(SwrContext *s, void *dst, int len, unsigned seed, enum AVSampleFormat noise_fmt) {

    double scale = s->dither.noise_scale;

#define TMP_EXTRA 2

    double *tmp = av_malloc_array(len + TMP_EXTRA, sizeof(double));

    int i;

    if (!tmp)

        return AVERROR(ENOMEM);

    for(i=0; i<len + TMP_EXTRA; i++){

        double v;

        seed = seed* 1664525 + 1013904223;

        switch(s->dither.method){

            case SWR_DITHER_RECTANGULAR: v= ((double)seed) / UINT_MAX - 0.5; break;

            default:

                av_assert0(s->dither.method < SWR_DITHER_NB);

                v = ((double)seed) / UINT_MAX;

                seed = seed*1664525 + 1013904223;

                v-= ((double)seed) / UINT_MAX;

                break;

        }

        tmp[i] = v;

    }

    for(i=0; i<len; i++){

        double v;

        switch(s->dither.method){

            default:

                av_assert0(s->dither.method < SWR_DITHER_NB);

                v = tmp[i];

                break;

            case SWR_DITHER_TRIANGULAR_HIGHPASS :

                v = (- tmp[i] + 2*tmp[i+1] - tmp[i+2]) / sqrt(6);

                break;

        }

        v*= scale;

        switch(noise_fmt){

            case AV_SAMPLE_FMT_S16P: ((int16_t*)dst)[i] = v; break;

            case AV_SAMPLE_FMT_S32P: ((int32_t*)dst)[i] = v; break;

            case AV_SAMPLE_FMT_FLTP: ((float  *)dst)[i] = v; break;

            case AV_SAMPLE_FMT_DBLP: ((double *)dst)[i] = v; break;

            default: av_assert0(0);

        }

    }

    av_free(tmp);

    return 0;

}

av_cold int swri_dither_init(SwrContext *s, enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt)

{

    int i;

    double scale = 0;

    if (s->dither.method > SWR_DITHER_TRIANGULAR_HIGHPASS && s->dither.method <= SWR_DITHER_NS)

        return AVERROR(EINVAL);

    out_fmt = av_get_packed_sample_fmt(out_fmt);

    in_fmt  = av_get_packed_sample_fmt( in_fmt);

    if(in_fmt == AV_SAMPLE_FMT_FLT || in_fmt == AV_SAMPLE_FMT_DBL){

        if(out_fmt == AV_SAMPLE_FMT_S32) scale = 1.0/(1LL<<31);

        if(out_fmt == AV_SAMPLE_FMT_S16) scale = 1.0/(1LL<<15);

        if(out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1.0/(1LL<< 7);

    }

    if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S32 && (s->dither.output_sample_bits&31)) scale = 1;

    if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S16) scale = 1<<16;

    if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1<<24;

    if(in_fmt == AV_SAMPLE_FMT_S16 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1<<8;

    scale *= s->dither.scale;

    if (out_fmt == AV_SAMPLE_FMT_S32 && s->dither.output_sample_bits)

        scale *= 1<<(32-s->dither.output_sample_bits);

    if (scale == 0) {

        s->dither.method = 0;

        return 0;

    }

    s->dither.ns_pos = 0;

    s->dither.noise_scale=   scale;

    s->dither.ns_scale   =   scale;

    s->dither.ns_scale_1 = scale ? 1/scale : 0;

    memset(s->dither.ns_errors, 0, sizeof(s->dither.ns_errors));

    for (i=0; filters[i].coefs; i++) {

        const filter_t *f = &filters[i];

        if (llabs(s->out_sample_rate - f->rate)*20 <= f->rate && f->name == s->dither.method) {

            int j;

            s->dither.ns_taps = f->len;

            for (j=0; j<f->len; j++)

                s->dither.ns_coeffs[j] = f->coefs[j];

            s->dither.ns_scale_1 *= 1 - exp(f->gain_cB * M_LN10 * 0.005) * 2 / (1<<(8*av_get_bytes_per_sample(out_fmt)));

            break;

        }

    }

    if (!filters[i].coefs && s->dither.method > SWR_DITHER_NS) {

        av_log(s, AV_LOG_WARNING, "Requested noise shaping dither not available at this sampling rate, using triangular hp dither\n");

        s->dither.method = SWR_DITHER_TRIANGULAR_HIGHPASS;

    }

    return 0;

}

#define TEMPLATE_DITHER_S16

#include "dither_template.c"

#undef TEMPLATE_DITHER_S16

#define TEMPLATE_DITHER_S32

#include "dither_template.c"

#undef TEMPLATE_DITHER_S32

#define TEMPLATE_DITHER_FLT

#include "dither_template.c"

#undef TEMPLATE_DITHER_FLT

#define TEMPLATE_DITHER_DBL

#include "dither_template.c"

#undef TEMPLATE_DITHER_DBL