src/gallium/auxiliary/vl/vl_csc.c

   1 #include "vl_csc.h"
   2 #include <util/u_math.h>
   3 #include <util/u_debug.h>
   4
   5 /*
   6  * Color space conversion formulas
   7  *
   8  * To convert YCbCr to RGB,
   9  *    vec4  ycbcr, rgb
  10  *    mat44 csc
  11  *    rgb = csc * ycbcr
  12  *
  13  * To calculate the color space conversion matrix csc with ProcAmp adjustments,
  14  *    mat44 csc, cstd, procamp, bias
  15  *    csc = cstd * (procamp * bias)
  16  *
  17  * Where cstd is a matrix corresponding to one of the color standards (BT.601, BT.709, etc)
  18  * adjusted for the kind of YCbCr -> RGB mapping wanted (1:1, full),
  19  * bias is a matrix corresponding to the kind of YCbCr -> RGB mapping wanted (1:1, full)
  20  *
  21  * To calculate procamp,
  22  *    mat44 procamp, hue, saturation, brightness, contrast
  23  *    procamp = brightness * (saturation * (contrast * hue))
  24  * Alternatively,
  25  *    procamp = saturation * (brightness * (contrast * hue))
  26  *
  27  * contrast
  28  * [ c, 0, 0, 0]
  29  * [ 0, c, 0, 0]
  30  * [ 0, 0, c, 0]
  31  * [ 0, 0, 0, 1]
  32  *
  33  * brightness
  34  * [ 1, 0, 0, b]
  35  * [ 0, 1, 0, 0]
  36  * [ 0, 0, 1, 0]
  37  * [ 0, 0, 0, 1]
  38  *
  39  * saturation
  40  * [ 1, 0, 0, 0]
  41  * [ 0, s, 0, 0]
  42  * [ 0, 0, s, 0]
  43  * [ 0, 0, 0, 1]
  44  *
  45  * hue
  46  * [ 1,       0,      0, 0]
  47  * [ 0,  cos(h), sin(h), 0]
  48  * [ 0, -sin(h), cos(h), 0]
  49  * [ 0,       0,      0, 1]
  50  *
  51  * procamp
  52  * [ c,           0,          0, b]
  53  * [ 0,  c*s*cos(h), c*s*sin(h), 0]
  54  * [ 0, -c*s*sin(h), c*s*cos(h), 0]
  55  * [ 0,           0,          0, 1]
  56  *
  57  * bias
  58  * [ 1, 0, 0,  ybias]
  59  * [ 0, 1, 0, cbbias]
  60  * [ 0, 0, 1, crbias]
  61  * [ 0, 0, 0,      1]
  62  *
  63  * csc
  64  * [ c*cstd[ 0], c*cstd[ 1]*s*cos(h) - c*cstd[ 2]*s*sin(h), c*cstd[ 2]*s*cos(h) + c*cstd[ 1]*s*sin(h), cstd[ 3] + cstd[ 0]*(b + c*ybias) + cstd[ 1]*(c*cbbias*s*cos(h) + c*crbias*s*sin(h)) + cstd[ 2]*(c*crbias*s*cos(h) - c*cbbias*s*sin(h))]
  65  * [ c*cstd[ 4], c*cstd[ 5]*s*cos(h) - c*cstd[ 6]*s*sin(h), c*cstd[ 6]*s*cos(h) + c*cstd[ 5]*s*sin(h), cstd[ 7] + cstd[ 4]*(b + c*ybias) + cstd[ 5]*(c*cbbias*s*cos(h) + c*crbias*s*sin(h)) + cstd[ 6]*(c*crbias*s*cos(h) - c*cbbias*s*sin(h))]
  66  * [ c*cstd[ 8], c*cstd[ 9]*s*cos(h) - c*cstd[10]*s*sin(h), c*cstd[10]*s*cos(h) + c*cstd[ 9]*s*sin(h), cstd[11] + cstd[ 8]*(b + c*ybias) + cstd[ 9]*(c*cbbias*s*cos(h) + c*crbias*s*sin(h)) + cstd[10]*(c*crbias*s*cos(h) - c*cbbias*s*sin(h))]
  67  * [ c*cstd[12], c*cstd[13]*s*cos(h) - c*cstd[14]*s*sin(h), c*cstd[14]*s*cos(h) + c*cstd[13]*s*sin(h), cstd[15] + cstd[12]*(b + c*ybias) + cstd[13]*(c*cbbias*s*cos(h) + c*crbias*s*sin(h)) + cstd[14]*(c*crbias*s*cos(h) - c*cbbias*s*sin(h))]
  68  */
  69
  70 /*
  71  * Converts ITU-R BT.601 YCbCr pixels to RGB pixels where:
  72  * Y is in [16,235], Cb and Cr are in [16,240]
  73  * R, G, and B are in [16,235]
  74  */
  75 static const float bt_601[16] =
  76 {
  77    1.0f,  0.0f,    1.371f, 0.0f,
  78    1.0f, -0.336f, -0.698f, 0.0f,
  79    1.0f,  1.732f,  0.0f,   0.0f,
  80    0.0f,  0.0f,    0.0f,   1.0f
  81 };
  82
  83 /*
  84  * Converts ITU-R BT.601 YCbCr pixels to RGB pixels where:
  85  * Y is in [16,235], Cb and Cr are in [16,240]
  86  * R, G, and B are in [0,255]
  87  */
  88 static const float bt_601_full[16] =
  89 {
  90    1.164f,  0.0f,    1.596f, 0.0f,
  91    1.164f, -0.391f, -0.813f, 0.0f,
  92    1.164f,  2.018f,  0.0f,   0.0f,
  93    0.0f,    0.0f,    0.0f,   1.0f
  94 };
  95
  96 /*
  97  * Converts ITU-R BT.709 YCbCr pixels to RGB pixels where:
  98  * Y is in [16,235], Cb and Cr are in [16,240]
  99  * R, G, and B are in [16,235]
 100  */
 101 static const float bt_709[16] =
 102 {
 103    1.0f,  0.0f,    1.540f, 0.0f,
 104    1.0f, -0.183f, -0.459f, 0.0f,
 105    1.0f,  1.816f,  0.0f,   0.0f,
 106    0.0f,  0.0f,    0.0f,   1.0f
 107 };
 108
 109 /*
 110  * Converts ITU-R BT.709 YCbCr pixels to RGB pixels where:
 111  * Y is in [16,235], Cb and Cr are in [16,240]
 112  * R, G, and B are in [0,255]
 113  */
 114 static const float bt_709_full[16] =
 115 {
 116    1.164f,  0.0f,    1.793f, 0.0f,
 117    1.164f, -0.213f, -0.534f, 0.0f,
 118    1.164f,  2.115f,  0.0f,   0.0f,
 119    0.0f,    0.0f,    0.0f,   1.0f
 120 };
 121
 122 static const float identity[16] =
 123 {
 124    1.0f, 0.0f, 0.0f, 0.0f,
 125    0.0f, 1.0f, 0.0f, 0.0f,
 126    0.0f, 0.0f, 1.0f, 0.0f,
 127    0.0f, 0.0f, 0.0f, 1.0f
 128 };
 129
 130 void vl_csc_get_matrix(enum VL_CSC_COLOR_STANDARD cs,
 131                        struct vl_procamp *procamp,
 132                        bool full_range,
 133                        float *matrix)
 134 {
 135    float ybias = full_range ? -16.0f/255.0f : 0.0f;
 136    float cbbias = -128.0f/255.0f;
 137    float crbias = -128.0f/255.0f;
 138    float c = procamp ? procamp->contrast : 1.0f;
 139    float s = procamp ? procamp->saturation : 1.0f;
 140    float b = procamp ? procamp->brightness : 0.0f;
 141    float h = procamp ? procamp->hue : 0.0f;
 142    const float *cstd;
 143
 144    assert(matrix);
 145
 146    switch (cs) {
 147       case VL_CSC_COLOR_STANDARD_BT_601:
 148          cstd = full_range ? &bt_601_full[0] : &bt_601[0];
 149          break;
 150       case VL_CSC_COLOR_STANDARD_BT_709:
 151          cstd = full_range ? &bt_709_full[0] : &bt_709[0];
 152          break;
 153       case VL_CSC_COLOR_STANDARD_IDENTITY:
 154       default:
 155          assert(cs == VL_CSC_COLOR_STANDARD_IDENTITY);
 156          memcpy(matrix, &identity[0], sizeof(float) * 16);
 157          return;
 158    }
 159
 160    matrix[ 0] = c*cstd[ 0];
 161    matrix[ 1] = c*cstd[ 1]*s*cosf(h) - c*cstd[ 2]*s*sinf(h);
 162    matrix[ 2] = c*cstd[ 2]*s*cosf(h) + c*cstd[ 1]*s*sinf(h);
 163    matrix[ 3] = cstd[ 3] + cstd[ 0]*(b + c*ybias) + cstd[ 1]*(c*cbbias*s*cosf(h) + c*crbias*s*sinf(h)) + cstd[ 2]*(c*crbias*s*cosf(h) - c*cbbias*s*sinf(h));
 164
 165    matrix[ 4] = c*cstd[ 4];
 166    matrix[ 5] = c*cstd[ 5]*s*cosf(h) - c*cstd[ 6]*s*sinf(h);
 167    matrix[ 6] = c*cstd[ 6]*s*cosf(h) + c*cstd[ 5]*s*sinf(h);
 168    matrix[ 7] = cstd[ 7] + cstd[ 4]*(b + c*ybias) + cstd[ 5]*(c*cbbias*s*cosf(h) + c*crbias*s*sinf(h)) + cstd[ 6]*(c*crbias*s*cosf(h) - c*cbbias*s*sinf(h));
 169
 170    matrix[ 8] = c*cstd[ 8];
 171    matrix[ 9] = c*cstd[ 9]*s*cosf(h) - c*cstd[10]*s*sinf(h);
 172    matrix[10] = c*cstd[10]*s*cosf(h) + c*cstd[ 9]*s*sinf(h);
 173    matrix[11] = cstd[11] + cstd[ 8]*(b + c*ybias) + cstd[ 9]*(c*cbbias*s*cosf(h) + c*crbias*s*sinf(h)) + cstd[10]*(c*crbias*s*cosf(h) - c*cbbias*s*sinf(h));
 174
 175    matrix[12] = c*cstd[12];
 176    matrix[13] = c*cstd[13]*s*cos(h) - c*cstd[14]*s*sin(h);
 177    matrix[14] = c*cstd[14]*s*cos(h) + c*cstd[13]*s*sin(h);
 178    matrix[15] = cstd[15] + cstd[12]*(b + c*ybias) + cstd[13]*(c*cbbias*s*cos(h) + c*crbias*s*sin(h)) + cstd[14]*(c*crbias*s*cos(h) - c*cbbias*s*sin(h));
 179 }