转换为YUV / YCbCr色彩空间 – 许多版本
YUV有许多不同的颜色转换，但它们都有不同的结果！ 哪一个正式正确？
这是我的测试程序的输出。 我输入R = 128 G = 50 B = 50（最大值为255）。 该表显示转换后的YUV值和重新转换的RGB值（与原始值不匹配）。
./ColourConversion.exe 128 50 50 YUVRGB Name =============================================================================== 0 0 0 128 50 50 a) Original RGB Values 79 116 162 128 50 49 b) Microsoft MSDN integer maths 78 116 162 126 49 47 c) ITU-R BT.601 73 120 162 127 49 49 d) HDTV ITU-R BT.709 73 114 202 176 25 48 e) RGB to full-range YCbCr 78 116 162 126 49 47 f) Book 'Video Demystified' 这是我的代码（在C＃中）：
using System; namespace ColourConversion { class MainClass { //Turn on debug to enter RGB values in 'red, geen & blue' public static bool debug = true; public static int red = 128; public static int green = 50; public static int blue = 50; //for printTidy() public static string alphabet = "abcdefghijklmnopqrstuvwxyz"; public static int testCount = 0; public static void Main (string[] args) { //init variables int r, g, b, R, G, B, Y, U, V, C, D, E; r = g = b = R = G = B = Y = U = V = C = D = E = 0; //read user input if not in debug mode if (!debug) { if (args.Length > 8) + 16; U = ((-38 * R - 74 * G + 112 * B + 128) >> 8) + 128; V = ((112 * R - 94 * G - 18 * B + 128) >> 8) + 128; C = Y - 16; D = U - 128; E = V - 128; R = clip ((298 * C + 409 * E + 128) >> 8); G = clip ((298 * C - 100 * D - 208 * E + 128) >> 8); B = clip ((298 * C + 516 * D + 128) >> 8); printTidy(Y,U,V,R,G,B, "Microsoft MSDN integer maths"); //--------------------------------------------------------------- //ITU-R BT.601 //http://www.equasys.de/colorconversion.html R = r; G = g; B = b; //http://sofzh.miximages.com/c%23/index.php Y = clip(16 + (0.257 * R + 0.504 * G + 0.098 * B)); U = clip(128 + (-0.148 * R + -0.291 * G + 0.439 * B)); V = clip(128 + (0.439 * R + -0.368 * G + -0.071 * B)); //http://sofzh.miximages.com/c%23/index.php R = clip(1.164 * (Y - 16) + 0.0 * (U - 128) + 1.596 * (V - 128)); G = clip(1.164 * (Y - 16) + -0.392 * (U - 128) + -0.813 * (V - 128)); B = clip(1.164 * (Y - 16) + 2.017 * (U - 128) + 0.0 * (V - 128)); printTidy(Y,U,V,R,G,B, "ITU-R BT.601"); //--------------------------------------------------------------- //HTDV ITU-R BT.709 //http://www.equasys.de/colorconversion.html R = r; G = g; B = b; //http://sofzh.miximages.com/c%23/index.php Y = clip(16 + ((0.183 * R) + (0.614 * G) + (0.062 * B))); U = clip(128 + ((-0.101 * R) + (-0.339 * G) + (0.439 * B))); V = clip(128 + ((0.439 * R) + (-0.399 * G) + (-0.040 * B))); //http://sofzh.miximages.com/c%23/index.php R = clip((1.164 * (Y-16)) + (0.0 * (U-128)) + (1.793 * (V-128))); G = clip((1.164 * (Y-16)) + (-0.213 * (U-128)) + (-0.533 * (V-128))); B = clip((1.164 * (Y-16)) + (2.112 * (U-128)) + (0.0 * (V-128))); printTidy(Y,U,V,R,G,B, "HDTV ITU-R BT.709"); //--------------------------------------------------------------- //RGB to full-range YCbCr //http://www.equasys.de/colorconversion.html R = r; G = g; B = b; //http://sofzh.miximages.com/c%23/index.php Y = clip(0.0 + ((0.299 * R) + (0.587 * G) + (0.114 * B))); U = clip(128.0 + ((-0.169 * R) + (-0.331 * G) + (0.500 * B))); V = clip(128.0 + ((0.500 * R) + (0.419 * G) + (-0.081 * R))); //http://sofzh.miximages.com/c%23/index.php R = clip((1.0 * Y) + (0.0 * (U - 128)) + (1.4 * (V - 128))); G = clip((1.0 * Y) + (-0.343 * (U - 128)) + (-0.711 * (V - 128))); B = clip((1.0 * Y) + (1.765 * (U - 128)) + (0.0 * (V - 128))); printTidy(Y,U,V,R,G,B, "RGB to full-range YCbCr"); //--------------------------------------------------------------- //Book 'Video Demystified' ISBN 1-878707-09-4 //http://www.fourcc.org/fccyvrgb.php R = r; G = g; B = b; Y = clip((0.257 * R) + (0.504 * G) + (0.098 * B) + 16); V = clip((0.439 * R) - (0.368 * G) - (0.071 * B) + 128); U = clip(-(0.148 * R) - (0.291 * G) + (0.439 * B) + 128); B = clip(1.164*(Y - 16) + 2.018*(U - 128)); G = clip(1.164*(Y - 16) - 0.813*(V - 128) - 0.391*(U - 128)); R = clip(1.164*(Y - 16) + 1.596*(V - 128)); printTidy(Y,U,V,R,G,B, "Book 'Video Demystified'"); } //Print output in a nice form public static void printTidy(int Y,int U,int V,int R,int G,int B, string methodName) { Console.Write(Y.ToString().PadLeft(10)); Console.Write(U.ToString().PadLeft(10)); Console.Write(V.ToString().PadLeft(10)); Console.Write(R.ToString().PadLeft(10)); Console.Write(G.ToString().PadLeft(10)); Console.Write(B.ToString().PadLeft(10)); Console.WriteLine(" " + alphabet[testCount++] + ") " + methodName); return; } //overload for clip() - converts double to int public static int clip (double d) { return clip((int)d); } //clips int to between 0 and 255 public static int clip (int i) { if (i 255) return 255; return i; } } }
没有“官方正确”，例如，BT.601适用于.DVvideo，而其他适用于其他标准……
YUV / YCbCr颜色的来源是什么？ 那将告诉你如何转换它。