1/*
2 Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>
3
4 This software is provided 'as-is', without any express or implied
5 warranty. In no event will the authors be held liable for any damages
6 arising from the use of this software.
7
8 Permission is granted to anyone to use this software for any purpose,
9 including commercial applications, and to alter it and redistribute it
10 freely.
11*/
12
13#include "SDL.h"
14
15#include "testyuv_cvt.h"
16
17
18static float clip3(float x, float y, float z)
19{
20 return ((z < x) ? x : ((z > y) ? y : z));
21}
22
23static void RGBtoYUV(Uint8 * rgb, int *yuv, SDL_YUV_CONVERSION_MODE mode, int monochrome, int luminance)
24{
25 if (mode == SDL_YUV_CONVERSION_JPEG) {
26 /* Full range YUV */
27 yuv[0] = (int)(0.299 * rgb[0] + 0.587 * rgb[1] + 0.114 * rgb[2]);
28 yuv[1] = (int)((rgb[2] - yuv[0]) * 0.565 + 128);
29 yuv[2] = (int)((rgb[0] - yuv[0]) * 0.713 + 128);
30 } else {
31 // This formula is from Microsoft's documentation:
32 // https://msdn.microsoft.com/en-us/library/windows/desktop/dd206750(v=vs.85).aspx
33 // L = Kr * R + Kb * B + (1 - Kr - Kb) * G
34 // Y = floor(2^(M-8) * (219*(L-Z)/S + 16) + 0.5);
35 // U = clip3(0, (2^M)-1, floor(2^(M-8) * (112*(B-L) / ((1-Kb)*S) + 128) + 0.5));
36 // V = clip3(0, (2^M)-1, floor(2^(M-8) * (112*(R-L) / ((1-Kr)*S) + 128) + 0.5));
37 float S, Z, R, G, B, L, Kr, Kb, Y, U, V;
38
39 if (mode == SDL_YUV_CONVERSION_BT709) {
40 /* BT.709 */
41 Kr = 0.2126f;
42 Kb = 0.0722f;
43 } else {
44 /* BT.601 */
45 Kr = 0.299f;
46 Kb = 0.114f;
47 }
48
49 S = 255.0f;
50 Z = 0.0f;
51 R = rgb[0];
52 G = rgb[1];
53 B = rgb[2];
54 L = Kr * R + Kb * B + (1 - Kr - Kb) * G;
55 Y = (Uint8)SDL_floorf((219*(L-Z)/S + 16) + 0.5f);
56 U = (Uint8)clip3(0, 255, SDL_floorf((112.0f*(B-L) / ((1.0f-Kb)*S) + 128) + 0.5f));
57 V = (Uint8)clip3(0, 255, SDL_floorf((112.0f*(R-L) / ((1.0f-Kr)*S) + 128) + 0.5f));
58
59 yuv[0] = (Uint8)Y;
60 yuv[1] = (Uint8)U;
61 yuv[2] = (Uint8)V;
62 }
63
64 if (monochrome) {
65 yuv[1] = 128;
66 yuv[2] = 128;
67 }
68
69 if (luminance != 100) {
70 yuv[0] = yuv[0] * luminance / 100;
71 if (yuv[0] > 255)
72 yuv[0] = 255;
73 }
74}
75
76static void ConvertRGBtoPlanar2x2(Uint32 format, Uint8 *src, int pitch, Uint8 *out, int w, int h, SDL_YUV_CONVERSION_MODE mode, int monochrome, int luminance)
77{
78 int x, y;
79 int yuv[4][3];
80 Uint8 *Y1, *Y2, *U, *V;
81 Uint8 *rgb1, *rgb2;
82 int rgb_row_advance = (pitch - w*3) + pitch;
83 int UV_advance;
84
85 rgb1 = src;
86 rgb2 = src + pitch;
87
88 Y1 = out;
89 Y2 = Y1 + w;
90 switch (format) {
91 case SDL_PIXELFORMAT_YV12:
92 V = (Y1 + h * w);
93 U = V + ((h + 1)/2)*((w + 1)/2);
94 UV_advance = 1;
95 break;
96 case SDL_PIXELFORMAT_IYUV:
97 U = (Y1 + h * w);
98 V = U + ((h + 1)/2)*((w + 1)/2);
99 UV_advance = 1;
100 break;
101 case SDL_PIXELFORMAT_NV12:
102 U = (Y1 + h * w);
103 V = U + 1;
104 UV_advance = 2;
105 break;
106 case SDL_PIXELFORMAT_NV21:
107 V = (Y1 + h * w);
108 U = V + 1;
109 UV_advance = 2;
110 break;
111 default:
112 SDL_assert(!"Unsupported planar YUV format");
113 return;
114 }
115
116 for (y = 0; y < (h - 1); y += 2) {
117 for (x = 0; x < (w - 1); x += 2) {
118 RGBtoYUV(rgb1, yuv[0], mode, monochrome, luminance);
119 rgb1 += 3;
120 *Y1++ = (Uint8)yuv[0][0];
121
122 RGBtoYUV(rgb1, yuv[1], mode, monochrome, luminance);
123 rgb1 += 3;
124 *Y1++ = (Uint8)yuv[1][0];
125
126 RGBtoYUV(rgb2, yuv[2], mode, monochrome, luminance);
127 rgb2 += 3;
128 *Y2++ = (Uint8)yuv[2][0];
129
130 RGBtoYUV(rgb2, yuv[3], mode, monochrome, luminance);
131 rgb2 += 3;
132 *Y2++ = (Uint8)yuv[3][0];
133
134 *U = (Uint8)SDL_floorf((yuv[0][1] + yuv[1][1] + yuv[2][1] + yuv[3][1])/4.0f + 0.5f);
135 U += UV_advance;
136
137 *V = (Uint8)SDL_floorf((yuv[0][2] + yuv[1][2] + yuv[2][2] + yuv[3][2])/4.0f + 0.5f);
138 V += UV_advance;
139 }
140 /* Last column */
141 if (x == (w - 1)) {
142 RGBtoYUV(rgb1, yuv[0], mode, monochrome, luminance);
143 rgb1 += 3;
144 *Y1++ = (Uint8)yuv[0][0];
145
146 RGBtoYUV(rgb2, yuv[2], mode, monochrome, luminance);
147 rgb2 += 3;
148 *Y2++ = (Uint8)yuv[2][0];
149
150 *U = (Uint8)SDL_floorf((yuv[0][1] + yuv[2][1])/2.0f + 0.5f);
151 U += UV_advance;
152
153 *V = (Uint8)SDL_floorf((yuv[0][2] + yuv[2][2])/2.0f + 0.5f);
154 V += UV_advance;
155 }
156 Y1 += w;
157 Y2 += w;
158 rgb1 += rgb_row_advance;
159 rgb2 += rgb_row_advance;
160 }
161 /* Last row */
162 if (y == (h - 1)) {
163 for (x = 0; x < (w - 1); x += 2) {
164 RGBtoYUV(rgb1, yuv[0], mode, monochrome, luminance);
165 rgb1 += 3;
166 *Y1++ = (Uint8)yuv[0][0];
167
168 RGBtoYUV(rgb1, yuv[1], mode, monochrome, luminance);
169 rgb1 += 3;
170 *Y1++ = (Uint8)yuv[1][0];
171
172 *U = (Uint8)SDL_floorf((yuv[0][1] + yuv[1][1])/2.0f + 0.5f);
173 U += UV_advance;
174
175 *V = (Uint8)SDL_floorf((yuv[0][2] + yuv[1][2])/2.0f + 0.5f);
176 V += UV_advance;
177 }
178 /* Last column */
179 if (x == (w - 1)) {
180 RGBtoYUV(rgb1, yuv[0], mode, monochrome, luminance);
181 *Y1++ = (Uint8)yuv[0][0];
182
183 *U = (Uint8)yuv[0][1];
184 U += UV_advance;
185
186 *V = (Uint8)yuv[0][2];
187 V += UV_advance;
188 }
189 }
190}
191
192static void ConvertRGBtoPacked4(Uint32 format, Uint8 *src, int pitch, Uint8 *out, int w, int h, SDL_YUV_CONVERSION_MODE mode, int monochrome, int luminance)
193{
194 int x, y;
195 int yuv[2][3];
196 Uint8 *Y1, *Y2, *U, *V;
197 Uint8 *rgb;
198 int rgb_row_advance = (pitch - w*3);
199
200 rgb = src;
201
202 switch (format) {
203 case SDL_PIXELFORMAT_YUY2:
204 Y1 = out;
205 U = out+1;
206 Y2 = out+2;
207 V = out+3;
208 break;
209 case SDL_PIXELFORMAT_UYVY:
210 U = out;
211 Y1 = out+1;
212 V = out+2;
213 Y2 = out+3;
214 break;
215 case SDL_PIXELFORMAT_YVYU:
216 Y1 = out;
217 V = out+1;
218 Y2 = out+2;
219 U = out+3;
220 break;
221 default:
222 SDL_assert(!"Unsupported packed YUV format");
223 return;
224 }
225
226 for (y = 0; y < h; ++y) {
227 for (x = 0; x < (w - 1); x += 2) {
228 RGBtoYUV(rgb, yuv[0], mode, monochrome, luminance);
229 rgb += 3;
230 *Y1 = (Uint8)yuv[0][0];
231 Y1 += 4;
232
233 RGBtoYUV(rgb, yuv[1], mode, monochrome, luminance);
234 rgb += 3;
235 *Y2 = (Uint8)yuv[1][0];
236 Y2 += 4;
237
238 *U = (Uint8)SDL_floorf((yuv[0][1] + yuv[1][1])/2.0f + 0.5f);
239 U += 4;
240
241 *V = (Uint8)SDL_floorf((yuv[0][2] + yuv[1][2])/2.0f + 0.5f);
242 V += 4;
243 }
244 /* Last column */
245 if (x == (w - 1)) {
246 RGBtoYUV(rgb, yuv[0], mode, monochrome, luminance);
247 rgb += 3;
248 *Y2 = *Y1 = (Uint8)yuv[0][0];
249 Y1 += 4;
250 Y2 += 4;
251
252 *U = (Uint8)yuv[0][1];
253 U += 4;
254
255 *V = (Uint8)yuv[0][2];
256 V += 4;
257 }
258 rgb += rgb_row_advance;
259 }
260}
261
262SDL_bool ConvertRGBtoYUV(Uint32 format, Uint8 *src, int pitch, Uint8 *out, int w, int h, SDL_YUV_CONVERSION_MODE mode, int monochrome, int luminance)
263{
264 switch (format)
265 {
266 case SDL_PIXELFORMAT_YV12:
267 case SDL_PIXELFORMAT_IYUV:
268 case SDL_PIXELFORMAT_NV12:
269 case SDL_PIXELFORMAT_NV21:
270 ConvertRGBtoPlanar2x2(format, src, pitch, out, w, h, mode, monochrome, luminance);
271 return SDL_TRUE;
272 case SDL_PIXELFORMAT_YUY2:
273 case SDL_PIXELFORMAT_UYVY:
274 case SDL_PIXELFORMAT_YVYU:
275 ConvertRGBtoPacked4(format, src, pitch, out, w, h, mode, monochrome, luminance);
276 return SDL_TRUE;
277 default:
278 return SDL_FALSE;
279 }
280}
281
282int CalculateYUVPitch(Uint32 format, int width)
283{
284 switch (format)
285 {
286 case SDL_PIXELFORMAT_YV12:
287 case SDL_PIXELFORMAT_IYUV:
288 case SDL_PIXELFORMAT_NV12:
289 case SDL_PIXELFORMAT_NV21:
290 return width;
291 case SDL_PIXELFORMAT_YUY2:
292 case SDL_PIXELFORMAT_UYVY:
293 case SDL_PIXELFORMAT_YVYU:
294 return 4*((width + 1)/2);
295 default:
296 return 0;
297 }
298}
299
300/* vi: set ts=4 sw=4 expandtab: */
301