libvo/csputils.c

   1 /*
   2  * Common code related to colorspaces and conversion
   3  *
   4  * Copyleft (C) 2009 Reimar Döffinger <Reimar.Doeffinger@gmx.de>
   5  *
   6  * This file is part of MPlayer.
   7  *
   8  * MPlayer is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * MPlayer is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22
  23 #include <stdint.h>
  24 #include <math.h>
  25 #include "libavutil/common.h"
  26 #include "csputils.h"
  27
  28 /**
  29  * \brief little helper function to create a lookup table for gamma
  30  * \param map buffer to create map into
  31  * \param size size of buffer
  32  * \param gamma gamma value
  33  */
  34 void mp_gen_gamma_map(uint8_t *map, int size, float gamma) {
  35   int i;
  36   if (gamma == 1.0) {
  37     for (i = 0; i < size; i++)
  38       map[i] = 255 * i / (size - 1);
  39     return;
  40   }
  41   gamma = 1.0 / gamma;
  42   for (i = 0; i < size; i++) {
  43     float tmp = (float)i / (size - 1.0);
  44     tmp = pow(tmp, gamma);
  45     if (tmp > 1.0) tmp = 1.0;
  46     if (tmp < 0.0) tmp = 0.0;
  47     map[i] = 255 * tmp;
  48   }
  49 }
  50
  51 /**
  52  * \brief get the coefficients of the yuv -> rgb conversion matrix
  53  * \param params struct specifying the properties of the conversion like brightness, ...
  54  * \param yuv2rgb array to store coefficients into
  55  *
  56  * Note: contrast, hue and saturation will only work as expected with YUV formats,
  57  * not with e.g. MP_CSP_XYZ
  58  */
  59 void mp_get_yuv2rgb_coeffs(struct mp_csp_params *params, float yuv2rgb[3][4]) {
  60   float uvcos = params->saturation * cos(params->hue);
  61   float uvsin = params->saturation * sin(params->hue);
  62   int format = params->format;
  63   int levelconv = params->levelconv;
  64   int i;
  65   const float (*uv_coeffs)[3];
  66   const float *level_adjust;
  67   static const float yuv_level_adjust[MP_CSP_LEVELCONV_COUNT][4] = {
  68     {-16 / 255.0, -128 / 255.0, -128 / 255.0, 1.164},
  69     { 16 / 255.0 * 1.164, -128 / 255.0, -128 / 255.0, 1.0/1.164},
  70     { 0, -128 / 255.0, -128 / 255.0, 1},
  71   };
  72   static const float xyz_level_adjust[4] = {0, 0, 0, 0};
  73   static const float uv_coeffs_table[MP_CSP_COUNT][3][3] = {
  74     [MP_CSP_DEFAULT] = {
  75       {1,  0.000,  1.596},
  76       {1, -0.391, -0.813},
  77       {1,  2.018,  0.000}
  78     },
  79     [MP_CSP_BT_601] = {
  80       {1,  0.000,  1.403},
  81       {1, -0.344, -0.714},
  82       {1,  1.773,  0.000}
  83     },
  84     [MP_CSP_BT_709] = {
  85       {1,  0.0000,  1.5701},
  86       {1, -0.1870, -0.4664},
  87       {1,  1.8556,  0.0000}
  88     },
  89     [MP_CSP_SMPTE_240M] = {
  90       {1,  0.0000,  1.5756},
  91       {1, -0.2253, -0.5000},
  92       {1,  1.8270,  0.0000}
  93     },
  94     [MP_CSP_EBU] = {
  95       {1,  0.000,  1.140},
  96       {1, -0.396, -0.581},
  97       {1,  2.029,  0.000}
  98     },
  99     [MP_CSP_XYZ] = {
 100       { 3.2404542, -1.5371385, -0.4985314},
 101       {-0.9692660,  1.8760108,  0.0415560},
 102       { 0.0556434, -0.2040259,  1.0572252}
 103     },
 104   };
 105
 106   if (format < 0 || format >= MP_CSP_COUNT)
 107     format = MP_CSP_DEFAULT;
 108   uv_coeffs = uv_coeffs_table[format];
 109   if (levelconv < 0 || levelconv >= MP_CSP_LEVELCONV_COUNT)
 110     levelconv = MP_CSP_LEVELCONV_TV_TO_PC;
 111   level_adjust = yuv_level_adjust[levelconv];
 112   if (format == MP_CSP_XYZ)
 113     level_adjust = xyz_level_adjust;
 114
 115   for (i = 0; i < 3; i++) {
 116     yuv2rgb[i][COL_C]  = params->brightness;
 117     yuv2rgb[i][COL_Y]  = uv_coeffs[i][COL_Y] * level_adjust[COL_C] * params->contrast;
 118     yuv2rgb[i][COL_C] += level_adjust[COL_Y] * yuv2rgb[i][COL_Y];
 119     yuv2rgb[i][COL_U]  = uv_coeffs[i][COL_U] * uvcos + uv_coeffs[i][COL_V] * uvsin;
 120     yuv2rgb[i][COL_C] += level_adjust[COL_U] * yuv2rgb[i][COL_U];
 121     yuv2rgb[i][COL_V]  = uv_coeffs[i][COL_U] * uvsin + uv_coeffs[i][COL_V] * uvcos;
 122     yuv2rgb[i][COL_C] += level_adjust[COL_V] * yuv2rgb[i][COL_V];
 123     // this "centers" contrast control so that e.g. a contrast of 0
 124     // leads to a grey image, not a black one
 125     yuv2rgb[i][COL_C] += 0.5 - params->contrast / 2.0;
 126   }
 127 }
 128
 129 //! size of gamma map use to avoid slow exp function in gen_yuv2rgb_map
 130 #define GMAP_SIZE (1024)
 131 /**
 132  * \brief generate a 3D YUV -> RGB map
 133  * \param params struct containing parameters like brightness, gamma, ...
 134  * \param map where to store map. Must provide space for (size + 2)^3 elements
 135  * \param size size of the map, excluding border
 136  */
 137 void mp_gen_yuv2rgb_map(struct mp_csp_params *params, unsigned char *map, int size) {
 138   int i, j, k, l;
 139   float step = 1.0 / size;
 140   float y, u, v;
 141   float yuv2rgb[3][4];
 142   unsigned char gmaps[3][GMAP_SIZE];
 143   mp_gen_gamma_map(gmaps[0], GMAP_SIZE, params->rgamma);
 144   mp_gen_gamma_map(gmaps[1], GMAP_SIZE, params->ggamma);
 145   mp_gen_gamma_map(gmaps[2], GMAP_SIZE, params->bgamma);
 146   mp_get_yuv2rgb_coeffs(params, yuv2rgb);
 147   for (i = 0; i < 3; i++)
 148     for (j = 0; j < 4; j++)
 149       yuv2rgb[i][j] *= GMAP_SIZE - 1;
 150   v = 0;
 151   for (i = -1; i <= size; i++) {
 152     u = 0;
 153     for (j = -1; j <= size; j++) {
 154       y = 0;
 155       for (k = -1; k <= size; k++) {
 156         for (l = 0; l < 3; l++) {
 157           float rgb = yuv2rgb[l][COL_Y] * y + yuv2rgb[l][COL_U] * u + yuv2rgb[l][COL_V] * v + yuv2rgb[l][COL_C];
 158           *map++ = gmaps[l][av_clip(rgb, 0, GMAP_SIZE - 1)];
 159         }
 160         y += (k == -1 || k == size - 1) ? step / 2 : step;
 161       }
 162       u += (j == -1 || j == size - 1) ? step / 2 : step;
 163     }
 164     v += (i == -1 || i == size - 1) ? step / 2 : step;
 165   }
 166 }