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 VMWARE 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/c]
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.709 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 [16,235]
114 */
115 static const vl_csc_matrix bt_709 =
116 {
117 { 1.0f, 0.0f, 1.540f, 0.0f, },
118 { 1.0f, -0.183f, -0.459f, 0.0f, },
119 { 1.0f, 1.816f, 0.0f, 0.0f, }
120 };
121
122 /*
123 * Converts SMPTE 240M 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 smpte240m =
128 {
129 { 1.0f, 0.0f, 1.541f, 0.0f, },
130 { 1.0f, -0.221f, -0.466f, 0.0f, },
131 { 1.0f, 1.785f, 0.0f, 0.0f, }
132 };
133
134 static const vl_csc_matrix bt_709_rev = {
135 { 0.183f, 0.614f, 0.062f, 0.0625f},
136 {-0.101f, -0.338f, 0.439f, 0.5f },
137 { 0.439f, -0.399f, -0.040f, 0.5f }
138 };
139
140 static const vl_csc_matrix identity =
141 {
142 { 1.0f, 0.0f, 0.0f, 0.0f, },
143 { 0.0f, 1.0f, 0.0f, 0.0f, },
144 { 0.0f, 0.0f, 1.0f, 0.0f, }
145 };
146
147 const struct vl_procamp vl_default_procamp = {
148 0.0f, /* brightness */
149 1.0f, /* contrast */
150 1.0f, /* saturation */
151 0.0f /* hue */
152 };
153
vl_csc_get_matrix(enum VL_CSC_COLOR_STANDARD cs,struct vl_procamp * procamp,bool full_range,vl_csc_matrix * matrix)154 void vl_csc_get_matrix(enum VL_CSC_COLOR_STANDARD cs,
155 struct vl_procamp *procamp,
156 bool full_range,
157 vl_csc_matrix *matrix)
158 {
159 float cbbias = -128.0f/255.0f;
160 float crbias = -128.0f/255.0f;
161
162 const struct vl_procamp *p = procamp ? procamp : &vl_default_procamp;
163 float c = p->contrast;
164 float s = p->saturation;
165 float b = p->brightness;
166 float h = p->hue;
167 float x, y;
168
169 const vl_csc_matrix *cstd;
170
171 if (full_range) {
172 c *= 1.164f; /* Adjust for the y range */
173 b *= 1.164f; /* Adjust for the y range */
174 b -= c * 16.0f / 255.0f; /* Adjust for the y bias */
175 }
176
177 /* Parameter substitutions */
178 x = c * s * cosf(h);
179 y = c * s * sinf(h);
180
181 assert(matrix);
182
183 switch (cs) {
184 case VL_CSC_COLOR_STANDARD_BT_601:
185 cstd = &bt_601;
186 break;
187 case VL_CSC_COLOR_STANDARD_BT_709:
188 cstd = &bt_709;
189 break;
190 case VL_CSC_COLOR_STANDARD_SMPTE_240M:
191 cstd = &smpte240m;
192 break;
193 case VL_CSC_COLOR_STANDARD_BT_709_REV:
194 memcpy(matrix, bt_709_rev, sizeof(vl_csc_matrix));
195 return;
196 case VL_CSC_COLOR_STANDARD_IDENTITY:
197 default:
198 assert(cs == VL_CSC_COLOR_STANDARD_IDENTITY);
199 memcpy(matrix, identity, sizeof(vl_csc_matrix));
200 return;
201 }
202
203 (*matrix)[0][0] = c * (*cstd)[0][0];
204 (*matrix)[0][1] = (*cstd)[0][1] * x - (*cstd)[0][2] * y;
205 (*matrix)[0][2] = (*cstd)[0][2] * x + (*cstd)[0][1] * y;
206 (*matrix)[0][3] = (*cstd)[0][3] + (*cstd)[0][0] * b +
207 (*cstd)[0][1] * (x * cbbias + y * crbias) +
208 (*cstd)[0][2] * (x * crbias - y * cbbias);
209
210 (*matrix)[1][0] = c * (*cstd)[1][0];
211 (*matrix)[1][1] = (*cstd)[1][1] * x - (*cstd)[1][2] * y;
212 (*matrix)[1][2] = (*cstd)[1][2] * x + (*cstd)[1][1] * y;
213 (*matrix)[1][3] = (*cstd)[1][3] + (*cstd)[1][0] * b +
214 (*cstd)[1][1] * (x * cbbias + y * crbias) +
215 (*cstd)[1][2] * (x * crbias - y * cbbias);
216
217 (*matrix)[2][0] = c * (*cstd)[2][0];
218 (*matrix)[2][1] = (*cstd)[2][1] * x - (*cstd)[2][2] * y;
219 (*matrix)[2][2] = (*cstd)[2][2] * x + (*cstd)[2][1] * y;
220 (*matrix)[2][3] = (*cstd)[2][3] + (*cstd)[2][0] * b +
221 (*cstd)[2][1] * (x * cbbias + y * crbias) +
222 (*cstd)[2][2] * (x * crbias - y * cbbias);
223 }
224