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1  /**************************************************************************
2   *
3   * Copyright 2009 Younes Manton.
4   * All Rights Reserved.
5   *
6   * Permission is hereby granted, free of charge, to any person obtaining a
7   * copy of this software and associated documentation files (the
8   * "Software"), to deal in the Software without restriction, including
9   * without limitation the rights to use, copy, modify, merge, publish,
10   * distribute, sub license, and/or sell copies of the Software, and to
11   * permit persons to whom the Software is furnished to do so, subject to
12   * the following conditions:
13   *
14   * The above copyright notice and this permission notice (including the
15   * next paragraph) shall be included in all copies or substantial portions
16   * of the Software.
17   *
18   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21   * IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
22   * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23   * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24   * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25   *
26   **************************************************************************/
27  
28  #include "util/u_math.h"
29  #include "util/u_debug.h"
30  
31  #include "vl_csc.h"
32  
33  /*
34   * Color space conversion formulas
35   *
36   * To convert YCbCr to RGB,
37   *    vec4  ycbcr, rgb
38   *    mat44 csc
39   *    rgb = csc * ycbcr
40   *
41   * To calculate the color space conversion matrix csc with ProcAmp adjustments,
42   *    mat44 csc, cstd, procamp, bias
43   *    csc = cstd * (procamp * bias)
44   *
45   * Where cstd is a matrix corresponding to one of the color standards (BT.601, BT.709, etc)
46   * adjusted for the kind of YCbCr -> RGB mapping wanted (1:1, full),
47   * bias is a matrix corresponding to the kind of YCbCr -> RGB mapping wanted (1:1, full)
48   *
49   * To calculate procamp,
50   *    mat44 procamp, hue, saturation, brightness, contrast
51   *    procamp = brightness * (saturation * (contrast * hue))
52   * Alternatively,
53   *    procamp = saturation * (brightness * (contrast * hue))
54   *
55   * contrast
56   * [ c, 0, 0, 0]
57   * [ 0, c, 0, 0]
58   * [ 0, 0, c, 0]
59   * [ 0, 0, 0, 1]
60   *
61   * brightness
62   * [ 1, 0, 0, b]
63   * [ 0, 1, 0, 0]
64   * [ 0, 0, 1, 0]
65   * [ 0, 0, 0, 1]
66   *
67   * saturation
68   * [ 1, 0, 0, 0]
69   * [ 0, s, 0, 0]
70   * [ 0, 0, s, 0]
71   * [ 0, 0, 0, 1]
72   *
73   * hue
74   * [ 1,       0,      0, 0]
75   * [ 0,  cos(h), sin(h), 0]
76   * [ 0, -sin(h), cos(h), 0]
77   * [ 0,       0,      0, 1]
78   *
79   * procamp
80   * [ c,           0,          0, b]
81   * [ 0,  c*s*cos(h), c*s*sin(h), 0]
82   * [ 0, -c*s*sin(h), c*s*cos(h), 0]
83   * [ 0,           0,          0, 1]
84   *
85   * bias
86   * [ 1, 0, 0,  ybias]
87   * [ 0, 1, 0, cbbias]
88   * [ 0, 0, 1, crbias]
89   * [ 0, 0, 0,      1]
90   *
91   * csc
92   * [ 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))]
93   * [ 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))]
94   * [ 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))]
95   * [ 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))]
96   */
97  
98  /*
99   * Converts ITU-R BT.601 YCbCr pixels to RGB pixels where:
100   * Y is in [16,235], Cb and Cr are in [16,240]
101   * R, G, and B are in [16,235]
102   */
103  static const vl_csc_matrix bt_601 =
104  {
105     { 1.0f,  0.0f,    1.371f, 0.0f, },
106     { 1.0f, -0.336f, -0.698f, 0.0f, },
107     { 1.0f,  1.732f,  0.0f,   0.0f, }
108  };
109  
110  /*
111   * Converts ITU-R BT.601 YCbCr pixels to RGB pixels where:
112   * Y is in [16,235], Cb and Cr are in [16,240]
113   * R, G, and B are in [0,255]
114   */
115  static const vl_csc_matrix bt_601_full =
116  {
117     { 1.164f,  0.0f,    1.596f, 0.0f, },
118     { 1.164f, -0.391f, -0.813f, 0.0f, },
119     { 1.164f,  2.018f,  0.0f,   0.0f, }
120  };
121  
122  /*
123   * Converts ITU-R BT.709 YCbCr pixels to RGB pixels where:
124   * Y is in [16,235], Cb and Cr are in [16,240]
125   * R, G, and B are in [16,235]
126   */
127  static const vl_csc_matrix bt_709 =
128  {
129     { 1.0f,  0.0f,    1.540f, 0.0f, },
130     { 1.0f, -0.183f, -0.459f, 0.0f, },
131     { 1.0f,  1.816f,  0.0f,   0.0f, }
132  };
133  
134  /*
135   * Converts ITU-R BT.709 YCbCr pixels to RGB pixels where:
136   * Y is in [16,235], Cb and Cr are in [16,240]
137   * R, G, and B are in [0,255]
138   */
139  static const vl_csc_matrix bt_709_full =
140  {
141     { 1.164f,  0.0f,    1.793f, 0.0f, },
142     { 1.164f, -0.213f, -0.534f, 0.0f, },
143     { 1.164f,  2.115f,  0.0f,   0.0f, }
144  };
145  
146  static const vl_csc_matrix smpte240m =
147  {
148     { 1.0f,  0.0f,    1.582f, 0.0f, },
149     { 1.0f, -0.228f, -0.478f, 0.0f, },
150     { 1.0f,  1.833f,  0.0f,   0.0f, }
151  };
152  
153  static const vl_csc_matrix smpte240m_full =
154  {
155     { 1.164f,  0.0f,    1.794f, 0.0f, },
156     { 1.164f, -0.258f, -0.543f, 0.0f, },
157     { 1.164f,  2.079f,  0.0f,   0.0f, }
158  };
159  
160  static const vl_csc_matrix identity =
161  {
162     { 1.0f, 0.0f, 0.0f, 0.0f, },
163     { 0.0f, 1.0f, 0.0f, 0.0f, },
164     { 0.0f, 0.0f, 1.0f, 0.0f, }
165  };
166  
167  const struct vl_procamp vl_default_procamp = {
168     0.0f,  /* brightness */
169     1.0f,  /* contrast   */
170     1.0f,  /* saturation */
171     0.0f   /* hue        */
172  };
173  
vl_csc_get_matrix(enum VL_CSC_COLOR_STANDARD cs,struct vl_procamp * procamp,bool full_range,vl_csc_matrix * matrix)174  void vl_csc_get_matrix(enum VL_CSC_COLOR_STANDARD cs,
175                         struct vl_procamp *procamp,
176                         bool full_range,
177                         vl_csc_matrix *matrix)
178  {
179     float ybias = full_range ? -16.0f/255.0f : 0.0f;
180     float cbbias = -128.0f/255.0f;
181     float crbias = -128.0f/255.0f;
182  
183     const struct vl_procamp *p = procamp ? procamp : &vl_default_procamp;
184     float c = p->contrast;
185     float s = p->saturation;
186     float b = p->brightness;
187     float h = p->hue;
188  
189     const vl_csc_matrix *cstd;
190  
191     assert(matrix);
192  
193     switch (cs) {
194        case VL_CSC_COLOR_STANDARD_BT_601:
195           cstd = full_range ? &bt_601_full : &bt_601;
196           break;
197        case VL_CSC_COLOR_STANDARD_BT_709:
198           cstd = full_range ? &bt_709_full : &bt_709;
199           break;
200        case VL_CSC_COLOR_STANDARD_SMPTE_240M:
201           cstd = full_range ? &smpte240m_full : &smpte240m;
202           break;
203        case VL_CSC_COLOR_STANDARD_IDENTITY:
204        default:
205           assert(cs == VL_CSC_COLOR_STANDARD_IDENTITY);
206           memcpy(matrix, identity, sizeof(vl_csc_matrix));
207           return;
208     }
209  
210     (*matrix)[0][0] = c * (*cstd)[0][0];
211     (*matrix)[0][1] = c * (*cstd)[0][1] * s * cosf(h) - c * (*cstd)[0][2] * s * sinf(h);
212     (*matrix)[0][2] = c * (*cstd)[0][2] * s * cosf(h) + c * (*cstd)[0][1] * s * sinf(h);
213     (*matrix)[0][3] = (*cstd)[0][3] + (*cstd)[0][0] * (b + c * ybias) +
214                       (*cstd)[0][1] * (c * cbbias * s * cosf(h) + c * crbias * s * sinf(h)) +
215                       (*cstd)[0][2] * (c * crbias * s * cosf(h) - c * cbbias * s * sinf(h));
216  
217     (*matrix)[1][0] = c * (*cstd)[1][0];
218     (*matrix)[1][1] = c * (*cstd)[1][1] * s * cosf(h) - c * (*cstd)[1][2] * s * sinf(h);
219     (*matrix)[1][2] = c * (*cstd)[1][2] * s * cosf(h) + c * (*cstd)[1][1] * s * sinf(h);
220     (*matrix)[1][3] = (*cstd)[1][3] + (*cstd)[1][0] * (b + c * ybias) +
221                       (*cstd)[1][1] * (c * cbbias * s * cosf(h) + c * crbias * s * sinf(h)) +
222                       (*cstd)[1][2] * (c * crbias * s * cosf(h) - c * cbbias * s * sinf(h));
223  
224     (*matrix)[2][0] = c * (*cstd)[2][0];
225     (*matrix)[2][1] = c * (*cstd)[2][1] * s * cosf(h) - c * (*cstd)[2][2] * s * sinf(h);
226     (*matrix)[2][2] = c * (*cstd)[2][2] * s * cosf(h) + c * (*cstd)[2][1] * s * sinf(h);
227     (*matrix)[2][3] = (*cstd)[2][3] + (*cstd)[2][0] * (b + c * ybias) +
228                       (*cstd)[2][1] * (c * cbbias * s * cosf(h) + c * crbias * s * sinf(h)) +
229                       (*cstd)[2][2] * (c * crbias * s * cosf(h) - c * cbbias * s * sinf(h));
230  }
231