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  1. /*
  2.  * Copyright (C) 2012-2013 Michael Niedermayer (michaelni@gmx.at)
  3.  *
  4.  * This file is part of libswresample
  5.  *
  6.  * libswresample is free software; you can redistribute it and/or
  7.  * modify it under the terms of the GNU Lesser General Public
  8.  * License as published by the Free Software Foundation; either
  9.  * version 2.1 of the License, or (at your option) any later version.
  10.  *
  11.  * libswresample is distributed in the hope that it will be useful,
  12.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14.  * Lesser General Public License for more details.
  15.  *
  16.  * You should have received a copy of the GNU Lesser General Public
  17.  * License along with libswresample; if not, write to the Free Software
  18.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19.  */
  20.  
  21. #include "libavutil/avassert.h"
  22. #include "swresample_internal.h"
  23.  
  24. #include "noise_shaping_data.c"
  25.  
  26. int swri_get_dither(SwrContext *s, void *dst, int len, unsigned seed, enum AVSampleFormat noise_fmt) {
  27.     double scale = s->dither.noise_scale;
  28. #define TMP_EXTRA 2
  29.     double *tmp = av_malloc_array(len + TMP_EXTRA, sizeof(double));
  30.     int i;
  31.  
  32.     if (!tmp)
  33.         return AVERROR(ENOMEM);
  34.  
  35.     for(i=0; i<len + TMP_EXTRA; i++){
  36.         double v;
  37.         seed = seed* 1664525 + 1013904223;
  38.  
  39.         switch(s->dither.method){
  40.             case SWR_DITHER_RECTANGULAR: v= ((double)seed) / UINT_MAX - 0.5; break;
  41.             default:
  42.                 av_assert0(s->dither.method < SWR_DITHER_NB);
  43.                 v = ((double)seed) / UINT_MAX;
  44.                 seed = seed*1664525 + 1013904223;
  45.                 v-= ((double)seed) / UINT_MAX;
  46.                 break;
  47.         }
  48.         tmp[i] = v;
  49.     }
  50.  
  51.     for(i=0; i<len; i++){
  52.         double v;
  53.  
  54.         switch(s->dither.method){
  55.             default:
  56.                 av_assert0(s->dither.method < SWR_DITHER_NB);
  57.                 v = tmp[i];
  58.                 break;
  59.             case SWR_DITHER_TRIANGULAR_HIGHPASS :
  60.                 v = (- tmp[i] + 2*tmp[i+1] - tmp[i+2]) / sqrt(6);
  61.                 break;
  62.         }
  63.  
  64.         v*= scale;
  65.  
  66.         switch(noise_fmt){
  67.             case AV_SAMPLE_FMT_S16P: ((int16_t*)dst)[i] = v; break;
  68.             case AV_SAMPLE_FMT_S32P: ((int32_t*)dst)[i] = v; break;
  69.             case AV_SAMPLE_FMT_FLTP: ((float  *)dst)[i] = v; break;
  70.             case AV_SAMPLE_FMT_DBLP: ((double *)dst)[i] = v; break;
  71.             default: av_assert0(0);
  72.         }
  73.     }
  74.  
  75.     av_free(tmp);
  76.     return 0;
  77. }
  78.  
  79. av_cold int swri_dither_init(SwrContext *s, enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt)
  80. {
  81.     int i;
  82.     double scale = 0;
  83.  
  84.     if (s->dither.method > SWR_DITHER_TRIANGULAR_HIGHPASS && s->dither.method <= SWR_DITHER_NS)
  85.         return AVERROR(EINVAL);
  86.  
  87.     out_fmt = av_get_packed_sample_fmt(out_fmt);
  88.     in_fmt  = av_get_packed_sample_fmt( in_fmt);
  89.  
  90.     if(in_fmt == AV_SAMPLE_FMT_FLT || in_fmt == AV_SAMPLE_FMT_DBL){
  91.         if(out_fmt == AV_SAMPLE_FMT_S32) scale = 1.0/(1LL<<31);
  92.         if(out_fmt == AV_SAMPLE_FMT_S16) scale = 1.0/(1LL<<15);
  93.         if(out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1.0/(1LL<< 7);
  94.     }
  95.     if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S32 && (s->dither.output_sample_bits&31)) scale = 1;
  96.     if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S16) scale = 1<<16;
  97.     if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1<<24;
  98.     if(in_fmt == AV_SAMPLE_FMT_S16 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1<<8;
  99.  
  100.     scale *= s->dither.scale;
  101.  
  102.     if (out_fmt == AV_SAMPLE_FMT_S32 && s->dither.output_sample_bits)
  103.         scale *= 1<<(32-s->dither.output_sample_bits);
  104.  
  105.     s->dither.ns_pos = 0;
  106.     s->dither.noise_scale=   scale;
  107.     s->dither.ns_scale   =   scale;
  108.     s->dither.ns_scale_1 = scale ? 1/scale : 0;
  109.     memset(s->dither.ns_errors, 0, sizeof(s->dither.ns_errors));
  110.     for (i=0; filters[i].coefs; i++) {
  111.         const filter_t *f = &filters[i];
  112.         if (llabs(s->out_sample_rate - f->rate)*20 <= f->rate && f->name == s->dither.method) {
  113.             int j;
  114.             s->dither.ns_taps = f->len;
  115.             for (j=0; j<f->len; j++)
  116.                 s->dither.ns_coeffs[j] = f->coefs[j];
  117.             s->dither.ns_scale_1 *= 1 - exp(f->gain_cB * M_LN10 * 0.005) * 2 / (1<<(8*av_get_bytes_per_sample(out_fmt)));
  118.             break;
  119.         }
  120.     }
  121.     if (!filters[i].coefs && s->dither.method > SWR_DITHER_NS) {
  122.         av_log(s, AV_LOG_WARNING, "Requested noise shaping dither not available at this sampling rate, using triangular hp dither\n");
  123.         s->dither.method = SWR_DITHER_TRIANGULAR_HIGHPASS;
  124.     }
  125.  
  126.     av_assert0(!s->preout.count);
  127.     s->dither.noise = s->preout;
  128.     s->dither.temp  = s->preout;
  129.     if (s->dither.method > SWR_DITHER_NS) {
  130.         s->dither.noise.bps = 4;
  131.         s->dither.noise.fmt = AV_SAMPLE_FMT_FLTP;
  132.         s->dither.noise_scale = 1;
  133.     }
  134.  
  135.     return 0;
  136. }
  137.  
  138. #define TEMPLATE_DITHER_S16
  139. #include "dither_template.c"
  140. #undef TEMPLATE_DITHER_S16
  141.  
  142. #define TEMPLATE_DITHER_S32
  143. #include "dither_template.c"
  144. #undef TEMPLATE_DITHER_S32
  145.  
  146. #define TEMPLATE_DITHER_FLT
  147. #include "dither_template.c"
  148. #undef TEMPLATE_DITHER_FLT
  149.  
  150. #define TEMPLATE_DITHER_DBL
  151. #include "dither_template.c"
  152. #undef TEMPLATE_DITHER_DBL
  153.