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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. void 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((len + TMP_EXTRA) * sizeof(double));
  30.     int i;
  31.  
  32.     for(i=0; i<len + TMP_EXTRA; i++){
  33.         double v;
  34.         seed = seed* 1664525 + 1013904223;
  35.  
  36.         switch(s->dither.method){
  37.             case SWR_DITHER_RECTANGULAR: v= ((double)seed) / UINT_MAX - 0.5; break;
  38.             default:
  39.                 av_assert0(s->dither.method < SWR_DITHER_NB);
  40.                 v = ((double)seed) / UINT_MAX;
  41.                 seed = seed*1664525 + 1013904223;
  42.                 v-= ((double)seed) / UINT_MAX;
  43.                 break;
  44.         }
  45.         tmp[i] = v;
  46.     }
  47.  
  48.     for(i=0; i<len; i++){
  49.         double v;
  50.  
  51.         switch(s->dither.method){
  52.             default:
  53.                 av_assert0(s->dither.method < SWR_DITHER_NB);
  54.                 v = tmp[i];
  55.                 break;
  56.             case SWR_DITHER_TRIANGULAR_HIGHPASS :
  57.                 v = (- tmp[i] + 2*tmp[i+1] - tmp[i+2]) / sqrt(6);
  58.                 break;
  59.         }
  60.  
  61.         v*= scale;
  62.  
  63.         switch(noise_fmt){
  64.             case AV_SAMPLE_FMT_S16P: ((int16_t*)dst)[i] = v; break;
  65.             case AV_SAMPLE_FMT_S32P: ((int32_t*)dst)[i] = v; break;
  66.             case AV_SAMPLE_FMT_FLTP: ((float  *)dst)[i] = v; break;
  67.             case AV_SAMPLE_FMT_DBLP: ((double *)dst)[i] = v; break;
  68.             default: av_assert0(0);
  69.         }
  70.     }
  71.  
  72.     av_free(tmp);
  73. }
  74.  
  75. int swri_dither_init(SwrContext *s, enum AVSampleFormat out_fmt, enum AVSampleFormat in_fmt)
  76. {
  77.     int i;
  78.     double scale = 0;
  79.  
  80.     if (s->dither.method > SWR_DITHER_TRIANGULAR_HIGHPASS && s->dither.method <= SWR_DITHER_NS)
  81.         return AVERROR(EINVAL);
  82.  
  83.     out_fmt = av_get_packed_sample_fmt(out_fmt);
  84.     in_fmt  = av_get_packed_sample_fmt( in_fmt);
  85.  
  86.     if(in_fmt == AV_SAMPLE_FMT_FLT || in_fmt == AV_SAMPLE_FMT_DBL){
  87.         if(out_fmt == AV_SAMPLE_FMT_S32) scale = 1.0/(1L<<31);
  88.         if(out_fmt == AV_SAMPLE_FMT_S16) scale = 1.0/(1L<<15);
  89.         if(out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1.0/(1L<< 7);
  90.     }
  91.     if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S32 && (s->dither.output_sample_bits&31)) scale = 1;
  92.     if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_S16) scale = 1L<<16;
  93.     if(in_fmt == AV_SAMPLE_FMT_S32 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<24;
  94.     if(in_fmt == AV_SAMPLE_FMT_S16 && out_fmt == AV_SAMPLE_FMT_U8 ) scale = 1L<<8;
  95.  
  96.     scale *= s->dither.scale;
  97.  
  98.     if (out_fmt == AV_SAMPLE_FMT_S32 && s->dither.output_sample_bits)
  99.         scale *= 1<<(32-s->dither.output_sample_bits);
  100.  
  101.     s->dither.ns_pos = 0;
  102.     s->dither.noise_scale=   scale;
  103.     s->dither.ns_scale   =   scale;
  104.     s->dither.ns_scale_1 = scale ? 1/scale : 0;
  105.     memset(s->dither.ns_errors, 0, sizeof(s->dither.ns_errors));
  106.     for (i=0; filters[i].coefs; i++) {
  107.         const filter_t *f = &filters[i];
  108.         if (fabs(s->out_sample_rate - f->rate) / f->rate <= .05 && f->name == s->dither.method) {
  109.             int j;
  110.             s->dither.ns_taps = f->len;
  111.             for (j=0; j<f->len; j++)
  112.                 s->dither.ns_coeffs[j] = f->coefs[j];
  113.             s->dither.ns_scale_1 *= 1 - exp(f->gain_cB * M_LN10 * 0.005) * 2 / (1<<(8*av_get_bytes_per_sample(out_fmt)));
  114.             break;
  115.         }
  116.     }
  117.     if (!filters[i].coefs && s->dither.method > SWR_DITHER_NS) {
  118.         av_log(s, AV_LOG_WARNING, "Requested noise shaping dither not available at this sampling rate, using triangular hp dither\n");
  119.         s->dither.method = SWR_DITHER_TRIANGULAR_HIGHPASS;
  120.     }
  121.  
  122.     av_assert0(!s->preout.count);
  123.     s->dither.noise = s->preout;
  124.     s->dither.temp  = s->preout;
  125.     if (s->dither.method > SWR_DITHER_NS) {
  126.         s->dither.noise.bps = 4;
  127.         s->dither.noise.fmt = AV_SAMPLE_FMT_FLTP;
  128.         s->dither.noise_scale = 1;
  129.     }
  130.  
  131.     return 0;
  132. }
  133.  
  134. #define TEMPLATE_DITHER_S16
  135. #include "dither_template.c"
  136. #undef TEMPLATE_DITHER_S16
  137.  
  138. #define TEMPLATE_DITHER_S32
  139. #include "dither_template.c"
  140. #undef TEMPLATE_DITHER_S32
  141.  
  142. #define TEMPLATE_DITHER_FLT
  143. #include "dither_template.c"
  144. #undef TEMPLATE_DITHER_FLT
  145.  
  146. #define TEMPLATE_DITHER_DBL
  147. #include "dither_template.c"
  148. #undef TEMPLATE_DITHER_DBL
  149.