Subversion Repositories Kolibri OS

Rev

Blame | Last modification | View Log | RSS feed

  1. /*
  2.  * This file is part of FFmpeg.
  3.  *
  4.  * FFmpeg is free software; you can redistribute it and/or
  5.  * modify it under the terms of the GNU Lesser General Public
  6.  * License as published by the Free Software Foundation; either
  7.  * version 2.1 of the License, or (at your option) any later version.
  8.  *
  9.  * FFmpeg is distributed in the hope that it will be useful,
  10.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12.  * Lesser General Public License for more details.
  13.  *
  14.  * You should have received a copy of the GNU Lesser General Public
  15.  * License along with FFmpeg; if not, write to the Free Software
  16.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17.  */
  18.  
  19. #include <stdint.h>
  20. #include "libavutil/avassert.h"
  21. #include "avfilter.h"
  22. #include "generate_wave_table.h"
  23.  
  24. void ff_generate_wave_table(enum WaveType wave_type,
  25.                             enum AVSampleFormat sample_fmt,
  26.                             void *table, int table_size,
  27.                             double min, double max, double phase)
  28. {
  29.     uint32_t i, phase_offset = phase / M_PI / 2 * table_size + 0.5;
  30.  
  31.     for (i = 0; i < table_size; i++) {
  32.         uint32_t point = (i + phase_offset) % table_size;
  33.         double d;
  34.  
  35.         switch (wave_type) {
  36.         case WAVE_SIN:
  37.             d = (sin((double)point / table_size * 2 * M_PI) + 1) / 2;
  38.             break;
  39.         case WAVE_TRI:
  40.             d = (double)point * 2 / table_size;
  41.             switch (4 * point / table_size) {
  42.             case 0: d = d + 0.5; break;
  43.             case 1:
  44.             case 2: d = 1.5 - d; break;
  45.             case 3: d = d - 1.5; break;
  46.             }
  47.             break;
  48.         default:
  49.             av_assert0(0);
  50.         }
  51.  
  52.         d  = d * (max - min) + min;
  53.         switch (sample_fmt) {
  54.         case AV_SAMPLE_FMT_FLT: {
  55.             float *fp = (float *)table;
  56.             *fp++ = (float)d;
  57.             table = fp;
  58.             continue; }
  59.         case AV_SAMPLE_FMT_DBL: {
  60.             double *dp = (double *)table;
  61.             *dp++ = d;
  62.             table = dp;
  63.             continue; }
  64.         }
  65.  
  66.         d += d < 0 ? -0.5 : 0.5;
  67.         switch (sample_fmt) {
  68.         case AV_SAMPLE_FMT_S16: {
  69.             int16_t *sp = table;
  70.             *sp++ = (int16_t)d;
  71.             table = sp;
  72.             continue; }
  73.         case AV_SAMPLE_FMT_S32: {
  74.             int32_t *ip = table;
  75.             *ip++ = (int32_t)d;
  76.             table = ip;
  77.             continue; }
  78.         default:
  79.             av_assert0(0);
  80.         }
  81.     }
  82. }
  83.  
  84.  
  85.