FFmpeg
colorspace.h
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1 /*
2  * Colorspace conversion defines
3  * Copyright (c) 2001, 2002, 2003 Fabrice Bellard
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * Various defines for YUV<->RGB conversion
25  */
26 
27 #ifndef AVUTIL_COLORSPACE_H
28 #define AVUTIL_COLORSPACE_H
29 
30 #define SCALEBITS 10
31 #define ONE_HALF (1 << (SCALEBITS - 1))
32 #define FIX(x) ((int) ((x) * (1<<SCALEBITS) + 0.5))
33 
34 #define YUV_TO_RGB1_CCIR(cb1, cr1)\
35 {\
36  cb = (cb1) - 128;\
37  cr = (cr1) - 128;\
38  r_add = FIX(1.40200*255.0/224.0) * cr + ONE_HALF;\
39  g_add = - FIX(0.34414*255.0/224.0) * cb - FIX(0.71414*255.0/224.0) * cr + \
40  ONE_HALF;\
41  b_add = FIX(1.77200*255.0/224.0) * cb + ONE_HALF;\
42 }
43 
44 #define YUV_TO_RGB1_CCIR_BT709(cb1, cr1) \
45  { \
46  cb = (cb1) - 128; \
47  cr = (cr1) - 128; \
48  r_add = ONE_HALF + FIX(1.5747 * 255.0 / 224.0) * cr; \
49  g_add = ONE_HALF - FIX(0.1873 * 255.0 / 224.0) * cb - \
50  FIX(0.4682 * 255.0 / 224.0) * cr; \
51  b_add = ONE_HALF + FIX(1.8556 * 255.0 / 224.0) * cb; \
52  }
53 
54 // To be used for the BT709 variant as well
55 #define YUV_TO_RGB2_CCIR(r, g, b, y1)\
56 {\
57  y = ((y1) - 16) * FIX(255.0/219.0);\
58  r = cm[(y + r_add) >> SCALEBITS];\
59  g = cm[(y + g_add) >> SCALEBITS];\
60  b = cm[(y + b_add) >> SCALEBITS];\
61 }
62 
63 #define YUV_TO_RGB1(cb1, cr1)\
64 {\
65  cb = (cb1) - 128;\
66  cr = (cr1) - 128;\
67  r_add = FIX(1.40200) * cr + ONE_HALF;\
68  g_add = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;\
69  b_add = FIX(1.77200) * cb + ONE_HALF;\
70 }
71 
72 #define YUV_TO_RGB2(r, g, b, y1)\
73 {\
74  y = (y1) << SCALEBITS;\
75  r = cm[(y + r_add) >> SCALEBITS];\
76  g = cm[(y + g_add) >> SCALEBITS];\
77  b = cm[(y + b_add) >> SCALEBITS];\
78 }
79 
80 #define Y_CCIR_TO_JPEG(y)\
81  cm[((y) * FIX(255.0/219.0) + (ONE_HALF - 16 * FIX(255.0/219.0))) >> SCALEBITS]
82 
83 #define Y_JPEG_TO_CCIR(y)\
84  (((y) * FIX(219.0/255.0) + (ONE_HALF + (16 << SCALEBITS))) >> SCALEBITS)
85 
86 #define C_CCIR_TO_JPEG(y)\
87  cm[(((y) - 128) * FIX(127.0/112.0) + (ONE_HALF + (128 << SCALEBITS))) >> SCALEBITS]
88 
89 /* NOTE: the clamp is really necessary! */
90 static inline int C_JPEG_TO_CCIR(int y) {
91  y = (((y - 128) * FIX(112.0/127.0) + (ONE_HALF + (128 << SCALEBITS))) >> SCALEBITS);
92  if (y < 16)
93  y = 16;
94  return y;
95 }
96 
97 
98 #define RGB_TO_Y_CCIR(r, g, b) \
99 ((FIX(0.29900*219.0/255.0) * (r) + FIX(0.58700*219.0/255.0) * (g) + \
100  FIX(0.11400*219.0/255.0) * (b) + (ONE_HALF + (16 << SCALEBITS))) >> SCALEBITS)
101 
102 #define RGB_TO_U_CCIR(r1, g1, b1, shift)\
103 (((- FIX(0.16874*224.0/255.0) * r1 - FIX(0.33126*224.0/255.0) * g1 + \
104  FIX(0.50000*224.0/255.0) * b1 + (ONE_HALF << shift) - 1) >> (SCALEBITS + shift)) + 128)
105 
106 #define RGB_TO_V_CCIR(r1, g1, b1, shift)\
107 (((FIX(0.50000*224.0/255.0) * r1 - FIX(0.41869*224.0/255.0) * g1 - \
108  FIX(0.08131*224.0/255.0) * b1 + (ONE_HALF << shift) - 1) >> (SCALEBITS + shift)) + 128)
109 
110 #define RGB_TO_Y_JPEG(r, g, b) \
111 (FFMIN((FIX(0.29900) * (r) + FIX(0.58700) * (g) + \
112  FIX(0.11400) * (b) + (ONE_HALF)) >> SCALEBITS, 255))
113 
114 #define RGB_TO_U_JPEG(r1, g1, b1)\
115 (((- FIX(0.16874) * r1 - FIX(0.33126) * g1 + \
116  FIX(0.50000) * b1 + (ONE_HALF) - 1) >> (SCALEBITS)) + 128)
117 
118 #define RGB_TO_V_JPEG(r1, g1, b1)\
119 (((FIX(0.50000) * r1 - FIX(0.41869) * g1 - \
120  FIX(0.08131) * b1 + (ONE_HALF) - 1) >> (SCALEBITS)) + 128)
121 
122 // Conversion macros for 8-bit RGB to YUV
123 // Derived from ITU-R BT.709-6 (06/2015) Item 3.5
124 // https://www.itu.int/rec/R-REC-BT.709-6-201506-I/en
125 
126 #define RGB_TO_Y_BT709(r, g, b) \
127 ((FIX(0.21260*219.0/255.0) * (r) + FIX(0.71520*219.0/255.0) * (g) + \
128  FIX(0.07220*219.0/255.0) * (b) + (ONE_HALF + (16 << SCALEBITS))) >> SCALEBITS)
129 
130 #define RGB_TO_U_BT709(r1, g1, b1, shift)\
131 (((- FIX(0.11457*224.0/255.0) * r1 - FIX(0.38543*224.0/255.0) * g1 + \
132  FIX(0.50000*224.0/255.0) * b1 + (ONE_HALF << shift) - 1) >> (SCALEBITS + shift)) + 128)
133 
134 #define RGB_TO_V_BT709(r1, g1, b1, shift)\
135 (((FIX(0.50000*224.0/255.0) * r1 - FIX(0.45415*224.0/255.0) * g1 - \
136  FIX(0.04585*224.0/255.0) * b1 + (ONE_HALF << shift) - 1) >> (SCALEBITS + shift)) + 128)
137 
138 #define RGB_TO_Y_BT709_FULL(r, g, b) \
139 (FFMIN((FIX(0.21260) * (r) + FIX(0.71520) * (g) + \
140  FIX(0.07220) * (b) + (ONE_HALF)) >> SCALEBITS, 255))
141 
142 #define RGB_TO_U_BT709_FULL(r1, g1, b1)\
143 (((- FIX(0.11457) * r1 - FIX(0.38543) * g1 + \
144  FIX(0.50000) * b1 + (ONE_HALF) - 1) >> (SCALEBITS)) + 128)
145 
146 #define RGB_TO_V_BT709_FULL(r1, g1, b1)\
147 (((FIX(0.50000) * r1 - FIX(0.45415) * g1 - \
148  FIX(0.04585) * b1 + (ONE_HALF) - 1) >> (SCALEBITS)) + 128)
149 
150 #endif /* AVUTIL_COLORSPACE_H */
#define ONE_HALF
Definition: colorspace.h:31
static int C_JPEG_TO_CCIR(int y)
Definition: colorspace.h:90
#define FIX(x)
Definition: colorspace.h:32
#define SCALEBITS
Definition: colorspace.h:30