vl_csc.c revision 14766f820069ca987543918bce96410c481e5d20 
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 */
103static 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 */
115static 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 */
127static 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 */
139static 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
146static 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
153static 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
160static 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
167const struct vl_procamp vl_default_procamp = {
168   0.0f,  /* brightness */
169   1.0f,  /* contrast   */
170   1.0f,  /* saturation */
171   0.0f   /* hue        */
172};
173
174void 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