testsuite/colorspace.c

   1
   2 #include <schroedinger/schro.h>
   3 #include <schroedinger/schroutils.h>
   4
   5 #include <stdio.h>
   6 #include <math.h>
   7 #include <string.h>
   8
   9 typedef struct _ColorMatrix ColorMatrix;
  10 struct _ColorMatrix {
  11   double m[4][4];
  12 };
  13
  14 void color_matrix_build (ColorMatrix *dst);
  15 void color_matrix_apply_u8 (ColorMatrix *m, uint8_t *dest, uint8_t *src);
  16 void color_matrix_apply_f64_u8 (ColorMatrix *m, double *dest, uint8_t *src);
  17 void color_matrix_dump(ColorMatrix *m);
  18
  19 uint8_t colors[][3] = {
  20   { 168, 44, 136 },
  21   { 61, 153, 99 },
  22   { 35, 174, 152 },
  23 #if 0
  24   { 235, 128, 128 },
  25   { 226, 0, 155 },
  26   { 179, 170, 0 },
  27   { 150, 46, 21 },
  28   { 105, 212, 235 },
  29   { 76, 85, 255 },
  30   { 29, 255, 107 },
  31   { 16, 128, 128 },
  32 #endif
  33 };
  34
  35 int
  36 main (int argc, char *argv[])
  37 {
  38   ColorMatrix m;
  39   double dest[3];
  40   //uint8_t src[3];
  41   int i;
  42
  43   color_matrix_build (&m);
  44   color_matrix_dump (&m);
  45   for(i=0;i<8;i++){
  46     color_matrix_apply_f64_u8 (&m, dest, colors[i]);
  47 #if 0
  48     src[0] = (i&2)?191:0;
  49     src[1] = (i&4)?191:0;
  50     src[2] = (i&1)?191:0;
  51     color_matrix_apply_f64_u8 (&m, dest, src);
  52 #endif
  53     printf("%8.4g %8.4g %8.4g\n", dest[0], dest[1], dest[2]);
  54   }
  55
  56   return 0;
  57 }
  58
  59
  60 void
  61 color_matrix_set_identity (ColorMatrix *m)
  62 {
  63   int i,j;
  64
  65   for(i=0;i<4;i++){
  66     for(j=0;j<4;j++){
  67       m->m[i][j] = (i==j);
  68     }
  69   }
  70 }
  71
  72 /* Prettyprint a 4x4 matrix @m@ */
  73 void
  74 color_matrix_dump(ColorMatrix *m)
  75 {
  76   int i,j;
  77
  78   printf("[\n");
  79   for (i = 0; i < 4; i++) {
  80     printf("  ");
  81     for (j = 0; j < 4; j++) {
  82       printf(" %8.5g", m->m[i][j]);
  83     }
  84     printf("\n");
  85   }
  86   printf("]\n");
  87 }
  88
  89 /* Perform 4x4 matrix multiplication:
  90  *  - @dst@ = @a@ * @b@
  91  *  - @dst@ may be a pointer to @a@ andor @b@
  92  */
  93 void
  94 color_matrix_multiply (ColorMatrix *dst, ColorMatrix *a, ColorMatrix *b)
  95 {
  96   ColorMatrix tmp;
  97   int i,j,k;
  98
  99   for (i = 0; i < 4; i++) {
 100     for (j = 0; j < 4; j++) {
 101       double x = 0;
 102       for (k = 0; k < 4; k++) {
 103         x += a->m[i][k] * b->m[k][j];
 104       }
 105       tmp.m[i][j] = x;
 106     }
 107   }
 108
 109   memcpy(dst, &tmp, sizeof(ColorMatrix));
 110 }
 111
 112
 113
 114 void
 115 color_matrix_offset_components (ColorMatrix *m, double a1, double a2,
 116     double a3)
 117 {
 118   ColorMatrix a;
 119
 120   color_matrix_set_identity (&a);
 121   a.m[0][3] = a1;
 122   a.m[1][3] = a2;
 123   a.m[2][3] = a3;
 124   color_matrix_multiply (m, &a, m);
 125 }
 126
 127 void
 128 color_matrix_scale_components (ColorMatrix *m, double a1, double a2,
 129     double a3)
 130 {
 131   ColorMatrix a;
 132
 133   color_matrix_set_identity (&a);
 134   a.m[0][0] = a1;
 135   a.m[1][1] = a2;
 136   a.m[2][2] = a3;
 137   color_matrix_multiply (m, &a, m);
 138 }
 139
 140 void
 141 color_matrix_YCbCr_to_RGB (ColorMatrix *m, double Kr, double Kb)
 142 {
 143   double Kg = 1.0 - Kr - Kb;
 144   ColorMatrix k = {
 145     {
 146       {1.,  0.,              2*(1-Kr),       0.},
 147       {1., -2*Kb*(1-Kb)/Kg, -2*Kr*(1-Kr)/Kg, 0.},
 148       {1.,  2*(1-Kb),        0.,             0.},
 149       {0.,  0.,              0.,             1.},
 150     }
 151   };
 152
 153   color_matrix_multiply (m, &k, m);
 154 }
 155
 156 void
 157 color_matrix_RGB_to_YCbCr (ColorMatrix *m, double Kr, double Kb)
 158 {
 159   double Kg = 1.0 - Kr - Kb;
 160   ColorMatrix k;
 161   double x;
 162
 163   k.m[0][0] = Kr;
 164   k.m[0][1] = Kg;
 165   k.m[0][2] = Kb;
 166   k.m[0][3] = 0;
 167
 168   x = 1/(2*(1-Kb));
 169   k.m[1][0] = -x*Kr;
 170   k.m[1][1] = -x*Kg;
 171   k.m[1][2] = x*(1-Kb);
 172   k.m[1][3] = 0;
 173
 174   x = 1/(2*(1-Kr));
 175   k.m[2][0] = x*(1-Kr);
 176   k.m[2][1] = -x*Kg;
 177   k.m[2][2] = -x*Kb;
 178   k.m[2][3] = 0;
 179
 180   k.m[3][0] = 0;
 181   k.m[3][1] = 0;
 182   k.m[3][2] = 0;
 183   k.m[3][3] = 1;
 184
 185   color_matrix_multiply (m, &k, m);
 186 }
 187
 188 void
 189 color_matrix_build (ColorMatrix *dst)
 190 {
 191 #if 0
 192   /*
 193    * At this point, everything is in YCbCr
 194    * All components are in the range [0,255]
 195    */
 196   color_matrix_set_identity (dst);
 197
 198   /* offset required to get input video black to (0.,0.,0.) */
 199   color_matrix_offset_components (dst, -16, -128, -128);
 200
 201   /* scale required to get input video black to (0.,0.,0.) */
 202   color_matrix_scale_components (dst, (1/219.0), (1/224.0), (1/224.0));
 203
 204   /* colour matrix, YCbCr -> RGB */
 205   /* Requires Y in [0,1.0], Cb&Cr in [-0.5,0.5] */
 206   color_matrix_YCbCr_to_RGB (dst, 0.2990, 0.1140);  // SD
 207   //color_matrix_YCbCr_to_RGB (dst, 0.2126, 0.0722);  // HD
 208
 209   /*
 210    * We are now in RGB space
 211    */
 212
 213   /* scale to output range. */
 214   color_matrix_scale_components (dst, 255.0, 255.0, 255.0);
 215 #else
 216   color_matrix_set_identity (dst);
 217
 218   color_matrix_scale_components (dst, (1/255.0), (1/255.0), (1/255.0));
 219
 220   color_matrix_RGB_to_YCbCr (dst, 0.2990, 0.1140); // SD
 221   //color_matrix_RGB_to_YCbCr (dst, 0.2126, 0.0722); // HD
 222   color_matrix_RGB_to_YCbCr (dst, 0.212, 0.087); // SMPTE 240M
 223
 224   color_matrix_scale_components (dst, 219.0, 224.0, 224.0);
 225
 226   color_matrix_offset_components (dst, 16, 128, 128);
 227 #endif
 228 }
 229
 230 void
 231 color_matrix_apply_u8 (ColorMatrix *m, uint8_t *dest, uint8_t *src)
 232 {
 233   int i;
 234
 235   for (i = 0; i < 3; i++) {
 236     double x = 0;
 237     x += m->m[i][0] * src[0];
 238     x += m->m[i][1] * src[1];
 239     x += m->m[i][2] * src[2];
 240     x += m->m[i][3];
 241     dest[i] = CLAMP(floor(x + 0.5),0,255);
 242   }
 243 }
 244
 245 void
 246 color_matrix_apply_f64_u8 (ColorMatrix *m, double *dest, uint8_t *src)
 247 {
 248   int i;
 249
 250   for (i = 0; i < 3; i++) {
 251     double x = 0;
 252     x += m->m[i][0] * src[0];
 253     x += m->m[i][1] * src[1];
 254     x += m->m[i][2] * src[2];
 255     x += m->m[i][3];
 256     dest[i] = CLAMP(floor(x + 0.5),0,255);
 257     //dest[i] = x;
 258   }
 259 }
 260
 261 /*
 262  * SMPTE 170M
 263  * ==========
 264  *
 265  * NTSC, SD, 525 lines
 266  *
 267  * color primaries:
 268  * "SMPTE C set"
 269  *  r 0.630 0.340
 270  *  g 0.310 0.595
 271  *  b 0.155 0.070
 272  * w D65
 273  *
 274  * "NTSC 1953"
 275  * r 0.67 0.33
 276  * g 0.21 0.71
 277  * b 0.14 0.08
 278  * w D65
 279  *
 280  * transfer function:
 281  *
 282  * LT= [(Vr + 0.099)/1.099]^(1/0.4500) for 0.0812 ≤ Vr ≤ 1
 283  * LT = Vr/4.500                       for 0 ≤ Vr < 0.0812
 284  *
 285  * also defines SD SMPTE color bars
 286  */
 287
 288 /*
 289  * EBU 3213-E
 290  * ==========
 291  *
 292  *  r 0.64 0.33
 293  *  g 0.29 0.60
 294  *  b 0.15 0.06
 295  *  w D65
 296  *
 297  */
 298
 299