/*

  * 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 "swresample_internal.h"
 

 #include "noise_shaping_data.c"
 

 void 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;
 

     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);

 }

 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/(1L<<31);
         if(out_fmt == AV_SAMPLE_FMT_S16) scale = 1.0/(1L<<15);
         if(out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1.0/(1L<< 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 = 1L<<16;
     if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<24;
     if(in_fmt == AV_SAMPLE_FMT_S16 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<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);
 

     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 (fabs(s->out_sample_rate - f->rate) / f->rate <= .05 && 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;
     }
 

     av_assert0(!s->preout.count);

     s->dither.noise = s->preout;

     s->dither.temp  = s->preout;

     if (s->dither.method > SWR_DITHER_NS) {
         s->dither.noise.bps = 4;
         s->dither.noise.fmt = AV_SAMPLE_FMT_FLTP;

         s->dither.noise_scale = 1;

     }

 
     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