vl_csc.c revision 5ed848129cb57269e80caf2c1ca522ae41f4500b 
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 float bt_601[16] =
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   0.0f,  0.0f,    0.0f,   1.0f
109};
110
111/*
112 * Converts ITU-R BT.601 YCbCr pixels to RGB pixels where:
113 * Y is in [16,235], Cb and Cr are in [16,240]
114 * R, G, and B are in [0,255]
115 */
116static const float bt_601_full[16] =
117{
118   1.164f,  0.0f,    1.596f, 0.0f,
119   1.164f, -0.391f, -0.813f, 0.0f,
120   1.164f,  2.018f,  0.0f,   0.0f,
121   0.0f,    0.0f,    0.0f,   1.0f
122};
123
124/*
125 * Converts ITU-R BT.709 YCbCr pixels to RGB pixels where:
126 * Y is in [16,235], Cb and Cr are in [16,240]
127 * R, G, and B are in [16,235]
128 */
129static const float bt_709[16] =
130{
131   1.0f,  0.0f,    1.540f, 0.0f,
132   1.0f, -0.183f, -0.459f, 0.0f,
133   1.0f,  1.816f,  0.0f,   0.0f,
134   0.0f,  0.0f,    0.0f,   1.0f
135};
136
137/*
138 * Converts ITU-R BT.709 YCbCr pixels to RGB pixels where:
139 * Y is in [16,235], Cb and Cr are in [16,240]
140 * R, G, and B are in [0,255]
141 */
142static const float bt_709_full[16] =
143{
144   1.164f,  0.0f,    1.793f, 0.0f,
145   1.164f, -0.213f, -0.534f, 0.0f,
146   1.164f,  2.115f,  0.0f,   0.0f,
147   0.0f,    0.0f,    0.0f,   1.0f
148};
149
150static const float identity[16] =
151{
152   1.0f, 0.0f, 0.0f, 0.0f,
153   0.0f, 1.0f, 0.0f, 0.0f,
154   0.0f, 0.0f, 1.0f, 0.0f,
155   0.0f, 0.0f, 0.0f, 1.0f
156};
157
158void vl_csc_get_matrix(enum VL_CSC_COLOR_STANDARD cs,
159                       struct vl_procamp *procamp,
160                       bool full_range,
161                       float *matrix)
162{
163   float ybias = full_range ? -16.0f/255.0f : 0.0f;
164   float cbbias = -128.0f/255.0f;
165   float crbias = -128.0f/255.0f;
166   float c = procamp ? procamp->contrast : 1.0f;
167   float s = procamp ? procamp->saturation : 1.0f;
168   float b = procamp ? procamp->brightness : 0.0f;
169   float h = procamp ? procamp->hue : 0.0f;
170   const float *cstd;
171
172   assert(matrix);
173
174   switch (cs) {
175      case VL_CSC_COLOR_STANDARD_BT_601:
176         cstd = full_range ? &bt_601_full[0] : &bt_601[0];
177         break;
178      case VL_CSC_COLOR_STANDARD_BT_709:
179         cstd = full_range ? &bt_709_full[0] : &bt_709[0];
180         break;
181      case VL_CSC_COLOR_STANDARD_IDENTITY:
182      default:
183         assert(cs == VL_CSC_COLOR_STANDARD_IDENTITY);
184         memcpy(matrix, &identity[0], sizeof(float) * 16);
185         return;
186   }
187
188   matrix[ 0] = c*cstd[ 0];
189   matrix[ 1] = c*cstd[ 1]*s*cosf(h) - c*cstd[ 2]*s*sinf(h);
190   matrix[ 2] = c*cstd[ 2]*s*cosf(h) + c*cstd[ 1]*s*sinf(h);
191   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));
192
193   matrix[ 4] = c*cstd[ 4];
194   matrix[ 5] = c*cstd[ 5]*s*cosf(h) - c*cstd[ 6]*s*sinf(h);
195   matrix[ 6] = c*cstd[ 6]*s*cosf(h) + c*cstd[ 5]*s*sinf(h);
196   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));
197
198   matrix[ 8] = c*cstd[ 8];
199   matrix[ 9] = c*cstd[ 9]*s*cosf(h) - c*cstd[10]*s*sinf(h);
200   matrix[10] = c*cstd[10]*s*cosf(h) + c*cstd[ 9]*s*sinf(h);
201   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));
202
203   matrix[12] = c*cstd[12];
204   matrix[13] = c*cstd[13]*s*cos(h) - c*cstd[14]*s*sin(h);
205   matrix[14] = c*cstd[14]*s*cos(h) + c*cstd[13]*s*sin(h);
206   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));
207}
208